School‐based interventions for improving contraceptive use in adolescents
Abstract
Background
Young women, especially adolescents, often lack access to modern contraception. Reasons vary by geography and regional politics and culture. The projected 2015 birth rate in 'developing' regions was 56 per 1000 compared with 17 per 1000 for 'developed' regions.
Objectives
To identify school‐based interventions that improved contraceptive use among adolescents
Search methods
Until 6 June 2016, we searched for eligible trials in PubMed, CENTRAL, ERIC, Web of Science, POPLINE, ClinicalTrials.gov and ICTRP.
Selection criteria
We considered randomized controlled trials (RCTs) that assigned individuals or clusters. The majority of participants must have been 19 years old or younger.
The educational strategy must have occurred primarily in a middle school or high school. The intervention had to emphasize one or more effective methods of contraception. Our primary outcomes were pregnancy and contraceptive use.
Data collection and analysis
We assessed titles and abstracts identified during the searches. One author extracted and entered the data into RevMan; a second author verified accuracy. We examined studies for methodological quality.
For unadjusted dichotomous outcomes, we calculated the Mantel‐Haenszel odds ratio (OR) with 95% confidence interval (CI). For cluster randomized trials, we used adjusted measures, e.g. OR, risk ratio, or difference in proportions. For continuous outcomes, we used the adjusted mean difference (MD) or other measures from the models. We did not conduct meta‐analysis due to varied interventions and outcome measures.
Main results
The 11 trials included 10 cluster RCTs and an individually randomized trial. The cluster RCTs had sample sizes from 816 to 10,954; the median number of clusters was 24. Most trials were conducted in the USA and UK; one was from Mexico and one from South Africa.
We focus here on the trials with moderate quality evidence and an intervention effect. Three addressed preventing pregnancy and HIV/STI through interactive sessions. One trial provided a multifaceted two‐year program. Immediately after year one and 12 months after year two, the intervention group was more likely than the standard‐curriculum group to report using effective contraception during last sex (reported adjusted ORs 1.62 ± standard error (SE) 0.22) and 1.76 ± SE 0.29), condom use during last sex (reported adjusted ORs 1.91 ± SE 0.27 and 1.68 ± SE 0.25), and less frequent sex without a condom in the past three months (reported ratios of adjusted means 0.50 ± SE 0.31 and 0.63 ± SE 0.23). Another trial compared multifaceted two‐year programs on sexual risk reduction and risk avoidance (abstinence‐focused) versus usual health education. At 3 months, the risk reduction group was less likely than the usual‐education group to report no condom use at last intercourse (reported adjusted OR 0.67, 95% CI 0.47 to 0.96) and sex without a condom in the last three months (reported adjusted OR 0.59, 95% CI 0.36 to 0.95). At 3 and after 15 months, the risk avoidance group was also less likely than the usual‐education group to report no condom use at last intercourse (reported adjusted ORs 0.70, 95% CI 0.52 to 0.93; and 0.61, 95% CI 0.45 to 0.85). At the same time points, the risk reduction group had a higher score than the usual‐education group for condom knowledge. The third trial provided a peer‐led program with eight interactive sessions. At 17 months, the intervention group was less likely than the teacher‐led group to report oral contraceptive use during last sex (OR 0.57, 95% CI 0.36 to 0.91). This difference may not have been significant if the investigators had adjusted for the clustering. At 5 and 17 months, the peer‐led group had a greater mean increase in knowledge of HIV and pregnancy prevention compared with the control group. An additional trial showed an effect on knowledge only. The group with an emergency contraception (EC) session was more likely than the group without the EC unit to know the time limits for using hormonal EC (pill) and the non‐hormonal IUD as EC.
Authors' conclusions
Since most trials addressed preventing STI/HIV and pregnancy, they emphasized condom use. However, several studies covered a range of contraceptive methods. The overall quality of evidence was low. Main reasons for downgrading the evidence were having limited information on intervention fidelity, analyzing a subsample rather than all those randomized, and having high losses.
PICOs
Plain language summary
School‐based programs to improve birth control use among adolescents
Background
Adolescents have high rates of unplanned pregnancy. They may not have family planning services nearby or know how to get modern birth control. We wanted to find programs in schools that helped teenagers learn about birth control.
Methods
We did computer searches for randomized trials until 6 June 2016. Programs included in this review must have occurred in a school, such as a middle school or high school. The programs tried to improve birth control use among teenagers. They also had to emphasize one or more methods of birth control known to work well.
Results
We found 11 trials. One study was small, and the other 10 had 816 to 10,954 participants. Six studies were from the USA, three were from the UK, and one each came from Mexico and South Africa. We focus here on three programs that had some effect and were good quality. All three involved students in a variety of activities versus usual sex education. After a two‐year program, the intervention group reported more use of birth control as well as condoms during last sex than the group with standard classes. Another study lasting two years provided two different programs. The intent was to avoid risk by not having sex until marriage or to reduce risk by delaying sex until older. The control group had usual health education. The programs for avoiding risk and reducing risk showed fewer reports of sex without using birth control or condoms. The third study had peers lead eight sessions of educational activities. The program showed less birth control use compared with teacher education but the researchers did not adjust for the study design.
Of the other eight studies, one had good quality results. The intervention group knew the time limits for using emergency contraception. Six of seven studies with low or very low quality results reported some program effect, such as more condom or contraceptive use or more knowledge of condoms.
Authors' conclusions
Since most trials aimed to prevent STI/HIV and pregnancy, they focused on condom use. However, several studies covered a variety of birth control methods. The overall quality of results was low. Some trials lacked information on how their programs worked. Many analyzed subsamples rather than all students in the study, and most had high losses.
Authors' conclusions
Summary of findings
| Interactive program on HIV/STI and pregnancy prevention compared with usual sex or health education for improving contraceptive use | ||||
| Patient or population: middle or high school students with need for contraceptive information Settings: school classroom Intervention: HIV/STI and pregnancy prevention Comparison: usual sex or health education | ||||
| Outcomes | Reported relative effect | Clusters; participants | Quality of evidence | Intervention; |
| Use of effective contraceptive during last sex: after year 1; 12 months after year 2 | Adjusted OR ± SE: 1.62 ± 0.22; 1.76 ± 0.29 | 20 schoolsa; 3869 students | ⊕⊕⊕⊝ | Multifaceted, 20‐lesson program vs standard HIV prevention (5 sessions + activities) 9th and 10th grades |
| Condom use at last sex: after year 1; 12 months after year 2 | Adjusted OR ± SE: 1.91 ± 0.27; 1.68 ± 0.25 | |||
| Frequency of sex without condom in last 3 months: 12 months after year 2 | Ratio of adjusted means ± SE: | |||
| No condom use at last vaginal sex (3 months) | OR 0.67 (0.47 to 0.96) | 15 schoolsa; 1742 students | ⊕⊕⊕⊝ | Sexual risk reduction (abstinence until older), 24 sessions vs usual health education; 7th and 8th grades |
| Vaginal sex without condom in past 3 months (3 months) | OR 0.59 (0.36 to 0.95) | |||
| No condom use at last vaginal sex: 3 months; 15 months | ORs: 0.70 (0.52 to 0.93); 0.61 (0.45 to 0.85) | Sexual risk avoidance (abstinence until marriage), 24 sessions vs usual health education; 7th and 8th grades | ||
| Oral contraceptive use during last sex (17 months) | OR 0.57 (0.36 to 0.91) | 102 middle‐school classesb; 2110 students | ⊕⊕⊕⊝ | Peer‐led interactive prevention (8 sessions) vs didactic teacher‐led sex education; 7th grade |
| CI: Confidence interval; MD = mean difference; OR: Odds Ratio; SE = standard error | ||||
| GRADE Working Group grade of evidence | ||||
| aRandomized schools | ||||
Background
Description of the condition
Internationally, access to modern contraceptive information and services for young women is considered a human rights issue (UNFPA 2011). Factors that limit access vary across geographic boundaries and according to regional politics and culture. Policies may prohibit young women, and especially adolescents, from obtaining certain contraceptive methods or any at all (Ross 2013; Chandra‐Mouli 2014). Adolescents may lack the knowledge, skills, or resources to obtain the available contraceptive information or to reach services. Their contraceptive use may be influenced by peers, social media, or the Internet; those sources may or may not provide accurate information. Attitudes and beliefs may lead parents, teachers, or providers to discourage teens from using contraception or to withhold information or services (Biddlecom 2008; Bankole 2010; Ross 2013). Unmarried or nulliparous women may not have access to the most effective methods such as intrauterine contraception (Wilson 2012; Rubin 2013).
Of the 16 million births each year to adolescents from 15 to 19 years old, 95% are in low‐ and middle‐income countries (LMICs) (Chandra‐Mouli 2014). The projected 2015 birth rate for young women in this age group was 116 per 1000 in sub‐Saharan Africa and 86 per 1000 young women in Latin America and the Caribbean (UN 2015). The projected average birth rate in 2015 for girls aged 15 to 19 years in developing regions was 56 per 1000, unchanged since 2000, compared with 17 per 1000 for developed regions, down from 26 in 2000. Complications from pregnancy and childbirth are the leading cause of death in this age group. Many adolescents choose abortion, which may be unsafe due to local restrictions. Three‐fourths of unsafe abortions, as well as other causes of maternal mortality, could be prevented by improved access to modern contraception (WHO 2014). In sub‐Saharan Africa and South Central Asia, two‐thirds of sexually active women aged 15 to 19 years want to avoid pregnancy but are not using a modern contraceptive method (Darroch 2011).
In the United States of America (USA), rates for teenage pregnancies, births, and abortions have decreased markedly since 1990. The pregnancy rate for teenagers was 57 per 1000 (6%) in 2010 compared to 117 per 1000 (12%) in 1990 (Kost 2014). The rate was twice as high when based on those who were sexually experienced. In 2008, 82% of the pregnancies in this age group were unintended (Finer 2014). Of teenage women at risk of unintended pregnancy in the USA, 59% reportedly use a highly effective contraceptive method, i.e. oral contraceptives or another hormonal method (Guttmacher 2015). However, in this age group, the male condom is the most common method at first sex and at most recent sex (Martinez 2011; Guttmacher 2015). Because of incorrect and inconsistent use, condoms are considered less effective than other modern methods. In a study of urban clinics in the USA, African American adolescents reported condoms alone as the most frequently used contraceptive method (35%) (Brown 2011a). Among never‐married adolescent females, reported condom use at last sex averaged 22% in West Africa, 35% in East Africa, and 60% in Southern Africa (Doyle 2012).
Description of the intervention
Schools provide a setting to reach many adolescents and to address pregnancy prevention with adolescent males as well as females (Taylor 2014). Schools offer the opportunity for reinforcement and social support of attitudes and behaviors about contraception. School interventions may include clinic‐based family planning services, as well as classroom education or school‐wide activities. Clinic services generally involve counseling or education, and may increase access to contraceptive methods (Blank 2010; Chandra‐Mouli 2014). Classroom‐based instruction may be a single session on contraception or a multisession curriculum on sexual health promotion. Sessions may be didactic or interactive, and may utilize technology for computer‐assisted assessments or instruction (Guse 2012). Program material may also be obtained from the Internet (Shegog 2014). School‐wide activities may include communication campaigns involving print or digital information, as well as interpersonal communications led by peer educators or school‐based clubs.
In many locations, intervention content has been focused on abstinence only, i.e. risk avoidance, due to governmental or local restrictions on contraception education for youth (Fonner 2014). Abstinence‐plus programs, also known as risk reduction or comprehensive sexual education, may encourage delaying sexual intercourse but also provide information on preventing disease and unintended pregnancy (Markham 2012; Fonner 2014). In the USA, a 2006 survey indicated 65% of high schools taught students how to find valid information on pregnancy prevention and 58% taught contraception methods in a health education course (CDC 2013a). According to a 2012 survey, 78% of school districts in the USA required teaching of pregnancy prevention in high schools, and 66% of middle schools required such education (CDC 2013b).
Where abstinence education is not a limiting factor, programs for adolescents often emphasize condom use. When used correctly and consistently, condoms can provide protection against both pregnancy and disease (CDC 2015). Failure of condoms to protect against sexually transmitted infections (STIs) or unintended pregnancy is usually due to inconsistent or incorrect use rather than condom breakage (CDC 2015). For the male condom, the estimated first‐year pregnancy rate with typical use is 18% and the rate for perfect use is 2% (Trussell 2011). Other contraceptive methods have lower failure rates, e.g. oral contraceptives at 9% for typical use and 0.3% with perfect use. Long‐acting reversible contraception (LARC), such as intrauterine contraception or an implant, does not require regular user action, and typical‐use failure rates for LARC are estimated at less than 1% (Trussell 2011).
Why it is important to do this review
This review examined school‐based interventions to improve the use of effective contraceptive methods among sexually active adolescents. The objectives of these interventions had to include preventing unintended pregnancy. Programs could have provided information on contraceptive methods available, the relative effectiveness of methods, and appropriate method use. Such efforts can help teenagers choose an appropriate contraceptive method and continue to use their preferred type. Since some adolescents have limited access to contraception due to lack of clinic transportation or cost of a method, educational programs may be combined with service provision.
Several reviews have examined educational strategies to prevent pregnancy or improve contraceptive use among adolescents; the scope of many has differed from the review proposed here. Some include interventions for preventing HIV or STIs as well as programs for pregnancy prevention (Chin 2012). Theory‐based interventions for youth may be implemented in schools or in the community (Lopez 2013a), either of which can support multifaceted programs. Reviews focused on school‐based programs may include studies of varying designs (Owen 2010) or interventions in universities as well as high schools (Blank 2010).
Given the number of interventions developed for young people, and adolescents in particular, we limited this review to those tested in randomized controlled trials. We tried to identify interventions that increase knowledge of contraception among teens and improve contraceptive use among those who are sexually active. The interventions should be feasible for middle or high school settings or the equivalent.
Objectives
To identify school‐based interventions that improved contraceptive use among adolescents
Methods
Criteria for considering studies for this review
Types of studies
We considered randomized controlled trials (RCTs) that assigned individuals as well as those that assigned clusters, e.g. classrooms or schools.
Types of participants
We were interested in interventions developed for adolescents, i.e. aged 19 years or younger. However, school‐based interventions are typically implemented in certain grades rather than provided to a specific age group. High schools or secondary schools may have students older than 19 years. For this review, the majority of participants must have been 19 years or younger. We did not set a lower age limit, as an intervention for younger adolescents may be provided to students by grade or class regardless of the students' ages.
The age range for adolescence and young adulthood varies in research and policymaking. Healthcare policy organizations may identify adolescence as ages 10 to 19 years (UN 2015; WHO 2015a). Others have considered 10 to 15 years old as the lower age cutoff for adolescence, and programs may include young people 18 to 24 years old (DHHS 2008; Gavin 2009). Contraceptive counseling for adolescents may focus on those aged 14 to 19 years old (Jaccard 2013). Peer education for sexual health among young people may include those to the age of 20 years (Tolli 2012). Contraceptive service interventions for young people in educational settings have participants up to 19 years of age (Blank 2010; Owen 2010).
Types of interventions
We considered educational strategies that occurred primarily in a school, such as a middle or high school, and addressed improving contraceptive use among adolescents. This did not preclude having some activities with parents or in the community, but most of the intervention must have been conducted within the school. We did not include interventions implemented in a college or university because the content and structure may differ when most the audience is older than our target group.
The behavioral strategy being tested had to address the use of one or more reversible methods of contraception. Interventions may have addressed preventing HIV and other STIs in addition to preventing pregnancy. Programs had to provide information on modern family planning methods (WHO 2015b) and include those considered more effective in preventing pregnancy. Effectiveness is 99% with correct and consistent use of the more effective methods, and typical‐use effectiveness ranges from 90% to 99% (Trussell 2011; WHO 2015b). These methods include pills, injectables, the contraceptive patch, the vaginal ring, lactational amenorrhea, and emergency contraception. In addition, typical‐use effectiveness for long‐acting methods such as intrauterine contraception and implants is greater than 99%. Of the fertility awareness‐based methods, sometimes known as 'natural family planning,' only the sympto‐thermal method may have typical‐use effectiveness of greater than 90%; effectiveness is 98% with correct and consistent use (WHO 2015b).
Types of outcome measures
Primary outcomes
We only included trials that had one of the following measures.
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Pregnancy (six months or more after the intervention began)
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Contraceptive use (three months or more after the intervention began)
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initiation of a new method
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improved use or continuation of a method
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Contraceptive use could have been assessed in various ways, e.g. consistent use or improved adherence. Where we found multiple measures within an included trial, we focused on the investigator’s assessment of consistent use or use at last sex. If we did not find one of those preferred outcomes, we accepted the measure used by the investigator, e.g. use of effective pregnancy prevention at last sex or sex without effective pregnancy prevention in the last three months.
The minimum time frame for contraception use assessment was three months after the intervention began, which indicates initiation of a method. For pregnancy assessment, the minimum time was six months. For high quality evidence, we required 6 months for contraceptive use and 12 months for pregnancy. The longer time frames provide more meaningful outcome measures.
Secondary outcomes
These measures may supplement the primary outcomes above. The study groups may differ after the intervention in their thinking about contraception, regardless of whether behavior changed.
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Knowledge of contraceptive effectiveness or effective method use
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Attitude about contraception or a specific contraceptive method
For inclusion of these outcomes, the time frame for assessment was three months or more after the baseline. For high quality evidence, we required at least six months.
Search methods for identification of studies
Electronic searches
Until 6 June 2016, we searched for eligible RCTs in PubMed, the Cochrane Central Register of Controlled Trials (CENTRAL), ERIC (Educational Resources Information Center), Web of Science, and POPLINE. We also searched for recent trials via ClinicalTrials.gov and the World Health Organization's International Clinical Trials Registry Platform (WHO ICTRP). Searches started from the inception of each database. Appendix 1 shows our search strategies.
Searching other resources
We examined reference lists of reviews and other relevant articles to find trials we may have missed in our electronic search.
Data collection and analysis
Selection of studies
We assessed for inclusion all titles and abstracts that the literature search identified. One author reviewed the search results and a second author examined the reports identified for appropriate categorization. For studies that appeared eligible for this review, we obtained and examined the full‐text articles. We resolved discrepancies by discussion.
Data extraction and management
Two authors conducted the data extraction. One author entered the data into Review Manager (RevMan 2014), and a second author checked accuracy. These data included the study characteristics, risk of bias, and outcomes. We focused on the primary and secondary outcomes for this review, which may not include all outcomes from each included trial. The authors resolved discrepancies through discussion.
Assessment of risk of bias in included studies
Intervention fidelity
We used an existing framework to assess the quality of the educational intervention (Borrelli 2011). This framework was developed for assessing treatment fidelity in public health trials of health behavior change. The principles were relevant for this systematic review of behavior change interventions. We examined the trial reports for evidence of intervention (or treatment) fidelity. Domains of treatment fidelity are study design, training of providers, delivery of treatment, receipt of treatment, and enactment of treatment skills. We list the criteria of interest for our review below.
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Study design: had a curriculum or treatment manual
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Prior training of providers: specified providers' credentials
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Project‐specific training: provided standardized training for the intervention
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Delivery: assessed providers' adherence to the protocol
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Receipt: assessed clients' understanding and skills regarding the intervention
For the assessment of evidence quality, we downgraded the trials that met fewer than four of the five listed criteria.
Research design
We evaluated the included trials for methodological quality in accordance with recommended principles (Higgins 2011), and entered the information into the 'Risk of bias' tables. We considered the randomization method, allocation concealment, blinding, and losses to follow‐up and early discontinuation.
Measures of treatment effect
For unadjusted dichotomous outcomes, we calculated the Mantel‐Haenszel odds ratio (OR) with 95% confidence interval (CI). This applied to an individually randomized trial or a cluster randomized trial that did not adjust for clustering. An example is the proportion of adolescents who used a condom with the last sexual intercourse. Fixed effect and random‐effects give the same result if no heterogeneity exists, as when a comparison includes only one study.
Cluster randomized trials may use a variety of strategies to account for the clustering. When available, we used adjusted measures that the investigators considered the primary effect measures. The adjusted odds ratio (OR) is commonly provided for dichotomous outcomes when analyses are obtained using cluster‐adjusted logit models with or without covariates. If an appropriate adjusted OR was unavailable from the report, we considered other effect measures, e.g. adjusted risk ratio, adjusted difference in proportions, or regression coefficient (adjusted beta). For continuous outcomes, we used the adjusted mean difference (MD), the adjusted beta, or other measure obtained from cluster‐adjusted linear models. Where the investigators used multivariate models, we did not analyze the treatment effect as that would usually require individual participant data. Rather we presented the results from adjusted models as reported by the investigators.
Unit of analysis issues
If clustering was part of the trial design, we assessed whether the investigators properly adjusted estimates to account for clustering effects. The cluster RCTs may use various methods of accounting for the clustering, such as multilevel modeling. We noted the specific methods the investigators used in the results for each trial.
Dealing with missing data
We wrote to trial investigators to request missing statistics, such as sample sizes for analysis and actual proportions or means for outcomes presented in figures. However, we limited our requests to studies less than 10 years old, as well as trials that had a report within the past five years. Investigators are unlikely to have access to data from older studies. In some cases, we had obtained information from investigators for earlier work that included the studies. If we could not analyze the data due to missing data, we presented the results as reported by the investigators.
Assessment of heterogeneity
We did not conduct meta‐analyses due to varied educational interventions and outcome measures and the use of adjusted analyses. Statistical heterogeneity was irrelevant. However, we addressed heterogeneity due to differences in trial design, populations, interventions, outcome measures, and analyses. For example, some trials focus on younger adolescents, many of whom had not yet initiated sex, while other trials include older adolescents. Location may influence the design, while the specific outcome measure may affect the ability to detect an effect. In addition, we synthesized results by the focus of the intervention and the methods used, e.g. didactic versus interactive or peer‐led versus teacher‐led.
Data synthesis
To assess the quality of evidence and address confidence in the effect estimates, we applied principles from GRADE (Grades of Recommendation, Assessment, Development and Evaluation) (Higgins 2011; GRADE 2013). If meta‐analysis is not viable because of varied interventions or outcome measures, a typical 'Summary of findings' table is not feasible. We do provide a 'Summary of findings' table for the main results although we did not conduct a formal GRADE assessment for all outcomes (GRADE 2013).
We assessed the body of evidence based on the quality of evidence from the included trials. Evidence quality includes the design, implementation, and reporting of the intervention and of the trial. The information on intervention fidelity is part of the overall assessment. We considered RCTs to be high quality and then downgraded the evidence based on the criteria below.
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Intervention fidelity information for fewer than four criteria
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Inadequate randomization sequence generation or allocation concealment, or no information provided for either one
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Analysis for primary outcome based on non‐randomized subsample, or analysis not adjusted for clustering
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Follow‐up less than 6 months for contraceptive use or less than 12 months for pregnancy
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Loss to follow‐up greater than 20%
We examined the trials that provided evidence of moderate quality and had sufficient outcome data. None of the studies met the criteria for having high quality evidence.
Results
Description of studies
Results of the search
The database searches yielded 628 unduplicated references (Figure 1). With 22 items from other sources the total was 650. We discarded 578 references based on the title or abstract. After reviewing the full text of 72 articles or abstracts, we excluded 51 items that did not meet the eligibility criteria (31 primary reports plus 20 secondary references). We included 21 items, i.e. 11 primary reports from studies that met the eligibility criteria plus 10 secondary references. Searches of clinical trials listings produced 50 unduplicated trials. Four trials are reportedly finished but have not yet produced outcome data (Studies awaiting classification). The other trials were irrelevant or from completed studies we had already considered.
Study flow diagram.
Included studies
Of 11 trials, 10 were cluster randomized, i.e. they assigned schools or classrooms, and one randomized individuals (Schinke 1981). Six trials were conducted in the USA, three were from the UK (Graham 2002; Wight 2002; Stephenson 2008), and one each came from Mexico (Walker 2006) and South Africa (Taylor 2014). Some interventions were targeted to younger adolescents, i.e. seventh‐ and eighth‐grade students, several focused on students aged 13 to 15 years, and one included high school students age 14 and older.
The trial reports were published from 1997 to 2014, except for a small RCT from 1981 (N = 36). Sample sizes for the cluster randomized trials ranged from 816 to 10,954 individuals with a median of 3794. The number of clusters ranged from 10 to 102; the median was 24. For the cluster RCTs, the effective sample sizes would be smaller due to the assignment of groups rather than individuals. Seven trials provided details on sample size calculations.
The number of contacts or sessions varied. The shortest experimental intervention involved a single unit on emergency contraception added to a standard curriculum. In contrast, four studies involved 20 to 24 sessions over two years.
Follow‐up ranged from 3 to 18 months postprogram. Two trials conducted follow‐up at more than four years through record review (Wight 2002; Stephenson 2008) and by survey (Stephenson 2008).
Excluded studies
We excluded 31 trials. Some did not use random assignment while others did not have our primary outcomes. For many studies, we could not find evidence of contraception education in the intervention. For details, see Characteristics of excluded studies.
Risk of bias in included studies
Figure 2 summarizes our assessments of risk of bias for the overall review; Figure 3 provides our assessment for each study.
Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.
Risk of bias summary: review authors' judgements about each risk of bias item for each included study.
We looked for evidence of intervention fidelity in the included studies (Table 1). Our assessment of evidence quality includes intervention fidelity reporting.
| Study | Curriculum or | Provider | Training for | Assessed adherence to protocol | Assessed intervention receipt | Fidelity |
| Pregnancy prevention | ||||||
| 14 sessions (50‐minute) for cognitive and behavioral training | Graduate students, 3 to 4 years counseling experience; not with teens regarding sex | _ | _ | Sessions involved problem solving, role play, rehearsal | 3 | |
| Resource pack of 20 lessons, piloted twice and revised; pilot‐test had evaluation with teachers and students | Classroom teachers | 5 days | Process evaluation: lesson observation (lessons covered; who led sessions) | Interaction on video with discussion; how to obtain condoms, practice use | 5 | |
| 12 weekly lessons with topics and activities; developed with formative research | 2 pairs, young, male and female trained facilitators | _ | _ | Lessons were interactive (role play, discussions, debates, videos) | 3 | |
| Emergency contraception | ||||||
| 1 EC lesson from resource for schools | Teachers | 2‐hour training for teachers to improve skill and knowledge; trainer was investigator training in family planning | _ | Lesson had scenario activity and quiz on EC (latter replaced role play after pilot; students had difficulty engaging) | 4 | |
| 15‐week course based on UN guidelines for school programs; 2 hours on EC | Teachers chosen by school | Week‐long (40‐hour) training + 2 hours on EC for schools with EC component | Investigators monitored via phone calls and visits with teachers and direct class observation | Classes included practice in communication, negotiation, and refusal skills; study assessed knowledge of HIV and of EC | 5 | |
| Preventing HIV/STI and pregnancy | ||||||
| Curriculum of 8 sessions over 2 weeks; specific topics and activities for each session | Peer educators hired and trained | 50 hours training to implement | Practiced delivering; had ongoing training and clinical supervision during implementation | Participants practiced skills and applied knowledge in program activities; assessed knowledge and attitudes | 5 | |
| 3 sessions with identified topics and activities; peer‐educators prepared lessons; intervention "standardized as far as possible" | Peer educators: 11th‐grade students Trainers: expertise in sexual health promotion | 2 days: sexual health, participatory learning, classroom management, group facilitation 3 pre‐training sessions for needs assessment + 1 follow‐up on lesson planning | Not specific: Observation for process data (not supervision) | Participatory sessions were interactive; involved practice | 4 | |
| 20 lessons; grades 9 and 10 (10 lessons each year) | School teachers; in‐class peer leaders for selected activities | Teachers had initial training and ongoing technical support | _ | In‐class peer leaders for some activities, role playing; homework (student‐parent, local resources) | 4 | |
| 14‐session curriculum; 9 class lessons and 5 units of service‐learning; pilot‐tested twice | Experienced health educators | Trained to implement; practiced during pilot | _ | Curriculum had experiential activities, e.g., creating posters, role playing, group discussion, guided skill practice. | 4 | |
| 24 lessons (45‐minute) developed with qualitative work and participatory methods | Trained facilitators | _ | _ | Sessions had computer‐based activities with quizzes, serials with on‐line student feedback, discussion | 3 | |
| 24 sessions (12 per year) of 50 min each; based on existing middle school program | Hired for program; most were African American or Hispanic with college degrees; experienced working with adolescents | 5‐day training; skilled trainers modeled lessons, provided teaching practice | Technical support during implementation | Assessed knowledge and self efficacy about sex and condom use | 5 | |
Allocation
Of the 11 included trials, seven provided information on the randomization process, such as restricted randomization, minimization strategy, or computer‐generated. Two only mentioned stratification (Taylor 2014; Walker 2006) and two provided no information (Kirby 1997; Schinke 1981).
The cluster randomized trials identified the clusters prior to randomization; all individuals meeting the inclusion criteria were eligible. We considered allocation concealment unclear if the report did not indicate whether the recruiters of individuals or the potential participants were aware of the cluster allocation prior to the consent process.
Blinding
Seven trials mentioned blinding. Two trials stated that participants and investigators or providers were not blinded (Graham 2002; Stephenson 2008). Five trials had some blinding of the assessors or data collection process (Schinke 1981; Graham 2002; Wight 2002; Tortolero 2010; Markham 2012). Double‐blinding is often not feasible for participants or providers in educational interventions. We found no mention of blinding for four trials (Coyle 2001; Coyle 2006; Walker 2006; Taylor 2014).
Incomplete outcome data
Loss to follow‐up was 20% or greater for seven trials. High loss to follow‐up threatens validity (Strauss 2005).
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Coyle 2001: 21% at 31 months after baseline (12 months after intervention)
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Coyle 2006: 27% after program; 38% at 6 months after program; 44% at 12 months after program
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Kirby 1997: 27% at 5 months after program; 23% at 17 months
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Markham 2012: 21% to 27% per group at 3 months (9th grade); 27% to 31% by 10th grade follow‐up
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Stephenson 2008: 13% intervention and 24% control at 6 months after program; 23% and 37% at 18 months; 48% and 62% at 54 months
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Walker 2006: 33% at 1 year after program
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Wight 2002: 31% at 6 months after program
For Tortolero 2010, loss to follow‐up was low but overall losses were high, i.e. 42% intervention and 34% comparison, mostly due to withdrawal from school or repeated absence. In addition, Taylor 2014 had differential losses (11% intervention and 23% control).
Other potential sources of bias
Of the 10 cluster RCTs, 9 used adjusted analysis to account for cluster effects. We did not have sufficient data for analysis in this review and therefore presented the results as reported by the investigators. The analysis in Kirby 1997 was the exception to that of the other cluster RCTs. The investigators planned to use hierarchical analysis to adjust for clustering if they found any positive differences in the behavioral outcomes. Some results may not have been significant if they had been adjusted for clustering. Schinke 1981 was the only trial that assigned individuals. The report did not have sufficient data for analysis here, so we presented the results as the investigators reported them.
Seven trials based the analysis of behavioral outcomes on a subsample of students who reported ever having sex or being sexually active, variables that the intervention could affect (Graham 2002; Wight 2002; Coyle 2006; Walker 2006; Stephenson 2008; Tortolero 2010; Taylor 2014). Those analyses did not include all students randomized, and therefore were not randomized comparisons. The results have a high risk of bias.
Effects of interventions
See: Summary of findings for the main comparison
We organized this section by intervention focus. Three studies focused on pregnancy prevention, and two more narrowly on emergency contraception (EC). Six trials covered a broad range of issues to prevent pregnancy as well as HIV/STI. Table 2 provides a summary of the interventions and the target audience for each study. In the analysis tables for 'other data,' NS refers to the study groups not being significantly different for that outcome.
| Study | Interventions | Special intervention sessions | Participants | Sample size | Location |
| Pregnancy prevention | |||||
| Cognitive and behavioral training vs assessment only | 14; 50 minutes each | Sophomores (2nd year high school) | 1 school; 36 students | USA | |
| Active learning + skill development vs usual sex education | 20; 10 in each of 2 years | 13 to 15 years old | 25 schools; 7616 students completed baseline surveys | Scotland | |
| Interactive program + usual life skills + media messages vs usual life skills and media messages | 12; weekly | Grade 8 (1st year high school) | 16 schools; 816 students completed baseline surveys | South Africa | |
| Emergency contraception | |||||
| Usual sex education + EC unit vs usual sex education | 1 on EC | Year 10 | 24 secondary schools; 3234 students completed baseline survey | England | |
| HIV prevention education + EC unit or HIV prevention education vs usual sex education | HIV prevention 30 hours over 15 weeks; EC 1 at 2 hours | Grade 10 | 40 schools; 10,954 students at baseline | Mexico | |
| Preventing HIV/STI and pregnancy | |||||
| Peer‐led interactive curriculum + didactic sex education vs didactic sex education | 8; over 2 weeks | Grade 7 | 102 classes (6 middle schools); approximately 2110 students completed baseline surveys | USA | |
| Peer‐led vs teacher‐led sex education | 3; 1 hour each | Grade 8 (age 13 to 14 years) | 27 schools; 8766 students at baseline | UK | |
| Multicomponent program vs standard HIV prevention curriculum | 20; 10 in each of 2 years | Grades 9 & 10 | 20 schools; 3869 students completed baseline surveys | USA | |
| Skills‐based curriculum + service learning vs usual prevention activities | 14 (9 + 5 service); over 5 to 7 weeks | Alternative day school (age 14 to 18+ years) | 24 schools; 988 students completed baseline surveys | USA | |
| Risk reduction vs usual health education | 24; 12 in each of 2 years | Grades 7 & 8 | 10 schools; 1307 students completed baseline surveys | USA | |
| Risk avoidance or risk reduction vs usual health education | 24; 12 in each of 2 years | Grades 7 & 8 | 15 schools; 1742 students completed baseline survey | USA | |
EC: emergency contraception
OC: oral contraceptive
Preventing pregnancy
Three trials focused on pregnancy prevention among high school students approximately 13 to 15 years old. A theory or model formed the basis of each experimental intervention. The programs differed in emphasis, activities, and duration.
The pregnancy prevention program of Schinke 1981 was based on cognitive and behavioral training, and used a problem‐solving schema. Content included sexuality, birth control, pregnancy. This USA trial randomized 36 individuals in one school to study groups. All the other trials assigned classes or schools. Participants were high school sophomores. Contact included 14 sessions of 50 minutes each. The control group only received the assessments, in contrast to the other included trials, which provided the comparison group some type of health education. The report provided results of t‐tests and did not clearly define the outcome variables. We did not request details due to the age of the publication. At the six‐month follow‐up, the students who received the training had a higher mean than the control group for "more habitual contraception" (reported t (32) = 2.38; P < 0.05), "greater protection at last intercourse" (reported t (32) = 3.26; P < 0.005), and less reliance on "inadequate birth control" (reported t (32) = 4.35; P < 0.001) (Analysis 1.1). The intervention group also had better attitudes toward family planning (reported t (32) = 2.08; P < 0.05) (Analysis 1.1). At the post‐test, the intervention group had higher mean scores than the control group for knowledge of human reproduction (t (34) = 3.40; P < 0.002) and of birth control (reported t (34) = 2.63; P < 0.02) (Analysis 1.2).
The intervention in Wight 2002 was based on social learning theory, and incorporated educational principles with which teachers were familiar to enhance acceptability. The 7616 participants were 13 to 15 years old, and attending 25 state schools in Scotland. The program included active learning and skill development in 20 sessions over two years. The control group received the usual sex education. To assign schools to treatment groups, the investigators selected an allocation from the set of 20,000 possible allocations, which provided the best balance of school‐level measures. To analyze the outcome of unwanted pregnancy, the investigators used a random effects logistics regression. For the other outcomes, they used a randomization test, based on all the possible allocations from which they selected the final allocation. The investigators based the analysis of behavioral outcomes at six months on a subsample of those who were sexually experienced, a variable that the intervention could affect. Since they did not include all those randomized, those comparisons were not randomized comparisons. At six months postprogram (or 24 months from baseline), the study groups were not significantly different for oral contraceptive (OC) use during last intercourse or self‐reported unwanted pregnancy (Analysis 2.1), first intercourse without condom use or no condom use during most recent intercourse (Analysis 2.2). By linking records from the National Health Service, the investigators examined pregnancies by age 20, approximately 4.5 years after the intervention. The termination data included live births, stillbirths, abortions, and miscarriages. The groups did not differ significantly in conceptions or terminations (Analysis 2.3).
For Taylor 2014, the pregnancy prevention intervention involved 12 weekly interactive sessions. Participants were in the first year of high school (grade eight) in KwaZulu‐Natal, South Africa. The study randomized 16 schools and had 816 participants. The conceptual framework was based on the I‐Change model. The special intervention addressed choice, body development, contraception, and parenthood. Both the intervention and comparison groups received the compulsory program on life skills plus media messages about teen pregnancy. The analysis corrected for cluster effect; multivariate linear and logistic regression models included covariates such as age, gender, socioeconomic status, and sexual experience. The investigators based the analysis of behavioral outcomes on a subsample that reported ever having sex, a variable that the intervention could affect. Since they did not include all those randomized, the comparisons were not randomized comparisons. The study groups did not differ significantly in self‐reported pregnancy (Analysis 3.1), and the groups did not differ for attitudes toward teen pregnancy (Analysis 3.2). The experimental group was more likely than the control group to report having any condom use (reported adjusted beta 0.98 ± SE 0.37; reported P < 0.01) (Analysis 3.1). The two groups did not differ significantly for condom use consistency (Analysis 3.2).
Emergency contraception
Two trials added a lesson on emergency contraception (EC) to an existing curriculum on sex education or HIV prevention. Both focused on students in grade 10. In Graham 2002, both groups received the usual sex education. The trial was conducted in 24 secondary schools in Avon, England. A total of 3234 students completed the baseline survey. To account for the clustering, the investigators weighted the regression analysis for schools rather than individuals. They analyzed by gender, and adjusted for baseline score and four factors in a minimization strategy. However, for EC use, the analyzed a subsample that reported ever having sex. Since they did not include all those randomized, this was not a randomized comparison. Among the girls or the boys, the study groups did not differ significantly for EC use by six months (Analysis 4.1). Knowledge of EC at six months did differ by group, and the analyses included all those randomized. The intervention group was more likely to know the time limit for hormonal EC use among girls (reported weighted percent difference 20.4, 95% CI 10.4 to 30.4; P < 0.01) and boys (reported weighted percent difference 15.9, 95% CI 6.5 to 25.3; P < 0.01) (Analysis 4.2). The group with EC education was also more likely to know the correct time limit for use of intrauterine contraception as EC, among the girls (reported weighted percent difference 10.7, 95% CI 0.4 to 21.0; P = 0.04) and the boys (reported weighted percent difference 4.2, 95% CI 0.7 to 7.7; P = 0.02) (Analysis 4.2).
For Walker 2006, two groups received an HIV prevention program with one also having the unit on EC. A third group had the usual sex education course. The trial took place in 40 schools in Moreles, Mexico and had 10,954 participants. The report mentions improved EC access as part of the special intervention, but does not provide further information. The Discussion mentions that EC is available at pharmacies without a prescription, but young people may have trouble accessing it thus affecting their results. The analysis reportedly took the cluster sample design into account. The investigators used fixed effect for regression and adjusted the standard errors for the number of primary sampling units for the descriptive statistics. However, they analyzed the behavioral outcomes for a subsample that reported being sexually active, a variable that the intervention could affect. Since they did not include all those randomized, those comparisons were not randomized comparisons. By one year, the study groups did not differ significantly for condom use at first sex or at last sex (Analysis 5.1). The group with HIV prevention + EC was more likely to have used EC compared with the group that had the usual sex education (reported adjusted OR 2.16, 95% CI 1.30 to 3.59) (Analysis 5.2). Analysis of knowledge outcomes included all those randomized. The HIV prevention + EC group was also more likely to have knowledge of EC at one year (reported adjusted OR 2.82, 95% CI 2.36 to 3.37) (Analysis 5.3). Those with HIV prevention alone (no EC unit) did not differ significantly from the group with usual sex education in use of EC (Analysis 5.2) or knowledge of EC (Analysis 5.3).
Preventing HIV/STI and pregnancy
Six trials tested curricula to prevent pregnancy and HIV or other STI. Two studies compared peer‐led versus teacher‐led sex education and two examined interactive programs versus usual sex education or prevention activities. The remaining two trials compared the same basic intervention for risk reduction versus usual health education, but one also had a third arm for risk avoidance. We list them by intervention focus and sessions provided.
Peer‐led versus teacher‐led sex education
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The program evaluated in Kirby 1997 provided eight interactive sessions over two weeks. The intervention group also had the same general sex education as the control group. Peer educators led the special interactive sessions. Students were in the seventh grade in Los Angeles, CA (USA). The 102 classes randomized included six middle schools and approximately 2110 students. In most schools, both the intervention and control groups received didactic sessions on reproductive health. Students were the unit of analysis. The evaluators intended to use hierarchical analysis to control for clustering if they found positive results. The study groups did not differ significantly in any of the behavioral outcomes, except for OC use being less likely for the intervention group (OR 0.57, 95% CI 0.36 to 0.91; participants = 354) (Analysis 6.1). This negative effect may not have been significant if the investigators had adjusted for the clustering. The other outcomes were reported condom use with last sex (Analysis 6.2) and ever been pregnant or gotten anyone pregnant (Analysis 6.3; Analysis 6.4). Based on a six‐item knowledge scale, the intervention group had a greater mean increase in knowledge of HIV and pregnancy prevention compared with the control group at both 5 months (reported mean increase 0.59 vs 0.07; P < 0.001) and 17 months (reported mean increase 0.89 vs 0.53; P < 0.001) (Analysis 6.5). Again, these effects were not adjusted for clustering.
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The special intervention in Stephenson 2008 involved three class sessions of one hour each, led by trained peers. The 8766 participants were grade eight students, 13 to 14 years old, in 27 UK schools. The investigators used general estimating equations, accounting for correlation within schools, and based on the robust variance estimator. As with Taylor 2014, they based the analysis of self‐reported behavioral outcomes on a subsample that reported ever having sex, for which the proportion increased by the length of follow‐up. Therefore, we did not consider the comparisons to be randomized comparisons. For pregnancy data, the investigators obtained self reports as well as long‐term follow‐up from national records of abortions and live births. In the 54‐month follow‐up, self reports of ever having a pregnancy indicated a lower rate for the intervention group compared to the control (reported weighted adjusted OR 0.62, 95% CI 0.42 to 0.91) (Analysis 7.1). Other pregnancy measures were not significantly different between the groups: no unintended pregnancy, ever had unwanted pregnancy, ever had abortion. Also, the study arms were not significantly different for the trial's primary outcome of abortion by age 20 nor for live births by age 20.5 (Analysis 7.2). The comparison groups did not differ significantly at any time point for contraceptive use (Analysis 7.3; Analysis 7.4), condom use (Analysis 7.5; Analysis 7.6), knowledge of EC pill timing (Analysis 7.7), or attitude about condom use (Analysis 7.8).
Interactive programs versus usual sex education or prevention activities
The curriculum in Coyle 2001 addressed using condoms and other contraception and included 20 sessions, divided between grades 9 and 10. The 20 randomized schools had 3869 students who completed baseline surveys. The program also included school organization activities and parent education. The comparison group received the standard five‐session curriculum and some school activities. The locations were in southeast Texas and northern California (USA). This cluster randomized trial accounted for the cluster effects in the analysis by using multilevel models. The investigators conducted assessments immediately after intervention year one and year two as well as 12 months after year two. Compared to the comparison group, the intervention group participants were more likely to report
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having used an effective method of contraception (condoms, OCs, or both) at last intercourse immediately after year one (reported adjusted OR 1.62 ± standard error (SE) 0.22; P = 0.03) and 12 months after year two (reported adjusted OR 1.76 ± SE 0.29; P = 0.05) (Analysis 8.1);
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having used a condom during last intercourse, as assessed immediately after year one (reported adjusted OR 1.91 ± SE 0.27; P = 0.02) and 12 months after year two (reported adjusted OR 1.68 ± SE 0.25; P = 0.04) (Analysis 8.2);
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a lower frequency of sex without condom use in the past three months, as assessed immediately after year one (reported ratio of adjusted means 0.50 ± SE 0.31; P = 0.03) and 12 months after year two (reported ratio of adjusted means 0.63 ± SE 0.23; P = 0.05) (Analysis 8.2);
The intervention group in Coyle 2001 also had a higher mean for positive attitudes about condoms immediately after year one (reported MD 0.10 ± SE 0.03; P < 0.01) and year two (reported MD 0.07; P < 0.01), as well as 12 months after year two (reported MD 0.07 ± SE 0.02; P = 0.01) (Analysis 8.3).
For Coyle 2006, the curriculum provided nine sessions of skill‐based learning plus five service‐learning activities in 24 alternative day schools in northern California (USA). The comparison group received the usual prevention activities for HIV, STI, and pregnancy. The schools served high school students with severe discipline issues, substance use, or chronic absenteeism. This cluster RCT accounted for the cluster effects in the analysis by using multilevel models. The study included 988 participants. The investigators based the analysis of behavioral outcomes on a subsample that reported ever having sex, a variable that the intervention could affect. Since they did not include all those randomized, we did not consider the comparisons to be randomized comparisons. The assessments at 6, 12, and 18 months after baseline were conducted about 5, 11, and 17 months postprogram.
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The study groups did not differ significantly for self‐reported pregnancy or using an effective method of pregnancy prevention at last sex (Analysis 9.1; Analysis 9.2).
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At 5 months but not 11 or 17 months, the intervention group was more likely than the usual‐activity group to report
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having used a condom during last intercourse (reported OR 2.12, 95% CI 1.24 to 3.56) (Analysis 9.3);
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less frequent sex without a condom in the past three months (reported adjusted MD ‐1.09 ± 0.36; P = 0.002) (Analysis 9.4).
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The intervention group had a higher mean for condom knowledge at 5 months (reported MD 0.055 ± 0.028; P = 0.05) and at 17 months (reported MD 0.060 ± 0.030; P = 0.04) (Analysis 9.5).
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The two groups did not differ significantly in their attitudes about condoms (Analysis 9.6).
Risk reduction or risk avoidance versus usual health education
Two USA studies provided 24 sessions across the seventh and eighth grades and used variations of the same curriculum. In Tortolero 2010, the focus was on delaying sexual behavior, although the intervention addressed a range of contraceptive methods and the relative effectiveness (see Characteristics of included studies). The comparison group had the usual health classes, which varied by school. The study included 1307 participants across the 10 schools randomized. In the analysis, the investigators used multilevel models that included the baseline measures of the dependent variable plus covariates judged to be potential confounders. However, they based the analysis of behavioral outcomes on a subsample that reported ever having sex, so the comparisons were not randomized comparisons. The study groups did not differ significantly in reported condom use at last sex, sex without a condom in the last three months, or sex without effective pregnancy prevention in the last three months (Analysis 10.1). For condom knowledge, the intervention group had a higher reported mean (2.41 ± SD 0.79) than the comparison group (2.25 ± SD 0.95) (reported P < 0.01) (Analysis 10.2). This analysis of knowledge did include all those randomized.
Markham 2012 included the risk reduction (RR) intervention from Tortolero 2010, which encouraged abstinence until older and a comparison group with the usual health classes, which varied by school. An additional third arm for risk avoidance (RA) focused on abstinence until marriage. As in Tortolero 2010, the intervention addressed a range of contraceptive methods and their relative effectiveness (see Characteristics of included studies). The 15 randomized schools included 1742 participants. The analysis involved generalized linear models with covariates; the estimated standard errors were adjusted for intraclass correlation via random‐effects models. Results came from reports in 2012 and 2014.
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At 3 months and after 15 months postprogram, the risk avoidance group was less likely than the control group to report unprotected vaginal sex at last intercourse (reported adjusted ORs 0.70, 95% CI 0.52 to 0.93; and 0.61, 95% CI 0.45 to 0.85, respectively) (Analysis 11.1). Protected sex included using a condom or abstaining from sex. The RA and control groups did not differ significantly for vaginal sex without a condom in the last three months (Analysis 11.2) or for general condom knowledge (Analysis 11.3).
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At three months postprogram, the risk reduction group was less likely than the control group to report unprotected sex at last vaginal intercourse (reported adjusted OR 0.67, 95% CI 0.47 to 0.96) (Analysis 11.1). Also at three months postprogram, the RR group was less likely to report vaginal sex without a condom in the last three months (reported adjusted OR 0.59, 95% CI 0.36 to 0.95) (Analysis 11.2). The RR group had a higher score for "general condom knowledge" at 3 months and after 15 months postprogram (reported adjusted MD 0.09 and 0.10, respectively; P < 0.01) (Analysis 11.3).
Discussion
Summary of main results
Table 3 summarizes the evidence quality for each included study and the evidence of effectiveness. We focus here on studies with moderate quality evidence.
| Study | Intervention fidelity < 4 items | Randomization; allocation concealment | Follow‐up period | Analysis | Loss > 20% | Evidence qualitya | Evidence of effectiveness |
| Pregnancy prevention | |||||||
| _ | _ | _ | ‐1 | ‐1 | Low | None | |
| ‐1 | ‐1 | _ | _ | _ | Low | Contraception use (6 months); unclear definitions | |
| ‐1 | _ | _ | ‐1 | ‐1 | Very low | Condom use, any (4 months) | |
| Emergency contraception | |||||||
| _ | _ | _ | ‐1 | _ | Moderate | Knew time limits for hormonal EC and for IUC as EC (6 months) | |
| _ | _ | _ | ‐1 | ‐1 | Low | HIV + EC group: used EC and had EC knowledge (1 year) | |
| Preventing HIV/STI and pregnancy | |||||||
| _ | _ | _ | ‐1 | _ | Moderate | OC use with last sex (17 months)b; mean knowledge increase (5 & 17 months) | |
| ‐1 | _ | _ | ‐1 | ‐1 | Very low | Ever pregnant, self report (54 months) | |
| _ | _ | _ | _ | ‐1 | Moderate | After year 1 & 12 months after year 2: less frequent sex without condom in past 3 months; condom use at last sex; use of effective contraceptive at last sex | |
| _ | _ | _ | ‐1 | ‐1 | Low | 5 months after program: less frequent sex without condom in past 3 months; condom use at last sex 5 & 17 months: | |
| ‐1 | _ | _ | ‐1 | ‐1 | Very low | Condom knowledge (24 months after baseline) | |
| _ | _ | _ | _ | ‐1 | Moderate | Risk avoidance group: Risk reduction group: sex without condom in last 3 months (3 months); | |
EC: emergency contraception
IUC: intrauterine contraception
OC: oral contraceptive
aDowngraded (‐1) for the following: (1) intervention fidelity < 4 criteria; (2) inadequate randomization sequence generation or allocation concealment, or no information on either; (3) analysis for primary outcome based on non‐randomized subsample, or analysis not adjusted for clustering; (4) follow‐up < 6 months for contraceptive use or < 12 months for pregnancy; (5) loss to follow‐up > 20%
bOC result favors control group; other differences favor experimental group. May not have been significant if investigators had adjusted for clustering.
Three trials had moderate quality evidence and showed intervention effects on one of our primary outcomes. i.e. pregnancy or contraceptive use. All three compared an interactive program to prevent HIV/STI and pregnancy versus usual health or sex education (summary of findings Table for the main comparison). Two were multifaceted programs provided over two years. In one trial, the intervention group was more likely than the standard curriculum group to report use of effective contraception during last sex, as assessed immediately after year one and 12 months after year two. At the same time points, the intervention group was more likely to report having used a condom during last sex and to have a lower reported frequency of sex without a condom in the past three months. The other multifaceted intervention provided a sexual risk reduction program and a risk avoidance (abstinence) program. The comparison was usual health education. At three months postprogram, the risk reduction group was less likely to report no condom use at last vaginal sex, as well as vaginal sex without a condom in the last three months. At 3 months and after 15 months, the risk avoidance group was less likely to report no condom use at last vaginal sex. The third trial provided a peer‐led intervention for HIV and pregnancy prevention that had eight interactive sessions. At 17 months, the intervention group was less likely to report OC use during last sex compared with the teacher‐led group. This negative effect may not have been significant if the investigators had adjusted for the clustering.
Our secondary outcomes were knowledge and attitudes about contraception. Three trials with moderate quality evidence showed intervention effects on knowledge. A multifaceted program noted above addressed risk reduction and risk avoidance. The risk reduction group had a higher score than the usual education group for condom knowledge at 3 months and after 15 months. For the trial with a peer‐led intervention discussed above, the experimental group had a greater mean increase in knowledge of HIV and pregnancy prevention compared with the control group at 5 and 17 months. Another trial with moderate quality evidence showed an effect on knowledge but not on a primary outcome. One group had a session on emergency contraception (EC) added to the usual sex education. The group with the EC unit was more likely than a group with usual education alone to know the time limits for using hormonal EC (pill) and for using the non‐hormonal intrauterine device (IUD) as EC.
Overall completeness and applicability of evidence
Most of the studies were conducted in higher income countries, i.e. the USA and the UK. One came from Mexico and one from South Africa. As noted earlier, the 2015 projected birth rate for girls aged 15 to 19 years in developing regions was three times that of developed regions (UN 2015). We did not have any representation from sub‐Saharan Africa or South Central Asia, where two‐thirds of sexually active women aged 15 to 19 years want to avoid pregnancy but are not using a modern contraceptive method (Darroch 2011). Fonner 2014 examined studies of school‐based sex education for HIV prevention in low‐ and middle‐income countries with a wide range of study designs. Using meta‐analysis, they found an intervention effect for condom use. However, they did not seek outcome data on pregnancy or contraceptive use since they were focused on HIV prevention.
The types of programs included were pregnancy prevention as well as preventing pregnancy and STI/HIV. The content regarding contraceptives often focused on condom use, perhaps in part because condoms are the most used contraceptive among adolescents. They are readily available at pharmacies in many regions. Also, condoms are the only contraceptive that can prevent transmission of HIV/STI, which was a large part of many programs. Several interventions also addressed oral contraceptives, also used by adolescents. Some programs ranked the relative effectiveness of modern and traditional contraceptive methods.
The number of sessions varied widely. Four interventions that provided 20 or more sessions over two years included a pregnancy prevention curriculum and programs to prevent pregnancy and HIV/STI. Five programs provided anywhere from 3 to 14 sessions. Two trials added a unit on EC to an existing sex education or HIV prevention curriculum.
Quality of the evidence
We considered the overall quality of evidence to be low. See Data synthesis for the criteria we used to grade the evidence. We rated the quality as moderate for four trials, low for four, and very low for three (Table 3). The main reasons for downgrading studies were having limited information on intervention fidelity, analyzing a subsample rather than all those randomized, and having high loss to follow‐up or discontinuation.
For educational settings, some study design features are rarely feasible. One example is blinding of participants and investigators to group assignment. Also, without a clinic, few options exist for an objective outcome measure of contraceptive use such as injection records for depot medroxyprogesterone acetate (DMPA) or electronic monitoring of pill intake. Further, trials of educational interventions often assess use of a range of contraceptive methods. An objective measure would be needed for each type of contraceptive reported.
Of five trials that assessed pregnancy, all had self reports for the main assessments. Under‐reporting is possible with self reports since women may not have reported an abortion. For long‐term follow‐up, two trials also used medical records of pregnancies and abortions, but they obtained those data at four years after the intervention.
Potential biases in the review process
Intervention information was limited for some older studies. We had to determine whether the trial addressed contraception sufficiently for inclusion or not. We attempted to gather related papers that addressed intervention content. However, we may have excluded trials that addressed contraceptive methods in more detail than the reports indicated. Similarly, outcomes measured may not have been fully reported if not significant. We did not contact investigators for missing data from older trials (see Dealing with missing data).
Agreements and disagreements with other studies or reviews
Some reviews of school‐based programs have focused on contraceptive service interventions (Blank 2010; Owen 2010). In Blank 2010, interventions were located in universities as well as high schools. They included both RCTs and non‐randomized studies, so results are not directly comparable to our review. Studies were limited in quantity and quality. The most effective interventions were reportedly intensive case management with a culturally matched social worker and school‐based health centers. Owen 2010 examined rates of sexual activity, use of school‐based services, and contraceptive use. The researchers found no good quality evidence of an intervention association with increased use of condoms or other contraceptives, and no evidence of effect on unplanned pregnancies.
We had searched for studies using digital media but did not find any that met our study design criteria. Guse 2012 reviewed the use of digital media for improving the sexual health of young people to age 24. They did not limit by type of study. Some programs were conducted in schools. Outcomes included STIs, HIV, and contraceptive use. They noted intervention effects for psychosocial outcomes such as condom self‐efficacy and abstinence attitudes and for knowledge of HIV, STI, or pregnancy.
Two reviews included interventions focused on adolescents but were not limited to school‐based programs. A review of theory‐based interventions to improve contraceptive use had 11 trials focused on adolescents (Lopez 2013a). Seven of those trials with adolescents showed an intervention effect, but only four had moderate or high quality evidence. One of the four was in this review and highlighted above (Summary of main results). The other three differed in focused from this review. They studied a clinic intervention for 18 to 24‐year‐old women, an intensive home‐based intervention for parenting teens, and a school‐based intervention focused more on use of condoms than other contraceptives. Another review examined interventions to prevent adolescent pregnancy (Oringanje 2016). The programs could have been based in schools, clinics, or the community, home, or faith group. They found that multiple interventions, e.g. education and promoting contraceptives, resulted in lower risk of unintended pregnancy in individually randomized trials but not cluster RCTs. They did not see an effect on contraceptive use with these types of interventions. Educational interventions increased reported condom use but did not affect pregnancy rates. Efforts to promote contraception led to an increase in hormonal method use but not to a decrease in pregnancy.
Several ongoing studies will add to the evidence base in the near future. These cluster randomized trials are all USA‐based. Shegog 2015a adapted the curriculum from Tortolero 2010 for American Indian or Alaskan Native youth. The investigators transferred the program to a web‐based format and added culturally relevant components. Constantine 2015 provided a 12‐session sexual 'rights‐based' curriculum for ninth graders to prevent pregnancy and STIs. The intervention included parent education and access to sexual health services for pregnancy and STI testing and prescriptions for contraceptives. The investigators have yet to report on behavioral outcomes. Two trials are evaluating a teen outreach program that has a school‐based curriculum and community service learning (Francis 2014; Buhi 2015).
Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.
Risk of bias summary: review authors' judgements about each risk of bias item for each included study.
| Study | Outcome | N | Reported t statistic | Reported P |
| Schinke 1981 | More habitual contraception | 32 | 2.38 | < 0.05 |
| Schinke 1981 | Greater protection at last sex | 32 | 3.26 | < 0.005 |
| Schinke 1981 | Less reliance on inadequate birth control | 32 | 4.35 | < 0.001 |
| Schinke 1981 | Attitudes toward family planning | 32 | 2.08 | < 0.05 |
Comparison 1 Pregnancy prevention education versus no education, Outcome 1 Contraceptive use and attitudes at 6 months.
| Study | Outcome | N | Reported t statistic | Reported P |
| Schinke 1981 | Knowledge of human reproduction | 34 | 3.40 | < 0.002 |
| Schinke 1981 | Knowledge of birth control | 34 | 2.63 | < 0.02 |
Comparison 1 Pregnancy prevention education versus no education, Outcome 2 Contraception knowledge at post‐test.
| Study | Outcome | Gender | N | Intervention | Control | Reported adjusted difference (95% CI) |
| Wight 2002 | Unwanted pregnancy (self report) | Young women | 2117 | 4.0% (48) | 3.8% (35) | 1.0 (0.6 to 1.8) |
| Wight 2002 | OC use during last sex | Young men | 876 | 18.7% (79) | 21.2% (96) | ‐2.5 (‐8.0 to 2.9) |
| Wight 2002 | OC use during last sex | Young women | 1269 | 30.4% (196) | 28.0% (175) | 2.4 (‐4.1 to 8.9) |
Comparison 2 Pregnancy prevention curriculum versus usual sex education, Outcome 1 Pregnancy and oral contraceptive use at 6 months postprogram (24 months).
| Study | Outcome | Gender | N | Intervention | Control | Reported adjusted difference (95% CI) |
| Wight 2002 | First‐time sex without condom after 1st program year | Young men | 2323 | 5.2% (57) | 5.7% (70) | ‐0.5 (‐2.5 to 1.5) |
| Wight 2002 | First‐time sex without condom after 1st program year | Young women | 2629 | 9.7% (127) | 9.1% (120) | 0.6 (‐1.9 to 3.1) |
| Wight 2002 | No condom during last sex | Young men | 876 | 33.6% (142) | 34.9% (158) | ‐1.3 (‐5.9 to 3.3) |
| Wight 2002 | No condom during last sex | Young women | 1269 | 44.9% (289) | 44.0% (275) | 0.9 (‐5.7 to 7.4) |
Comparison 2 Pregnancy prevention curriculum versus usual sex education, Outcome 2 Condom use at 6 months postprogram (24 months).
| Study | Outcome | Intervention rate/1000 | Control rate/1000 | Reported adjusted difference (95% CI) |
| Wight 2002 | Termination events | 126.6 | 112.0 | 15.7 (‐10.7 to 42.1) |
| Wight 2002 | Conception events (live births, stillbirths, therapeutic terminations, miscarriages) | 300.2 | 273.8 | 31.9 (‐16.1 to 79.9) |
| Wight 2002 | Had > 1 termination | 108.9 | 104.3 | 5.6 (‐16.0 to 27.2) |
| Wight 2002 | Had > 1 conception | 222.6 | 216.8 | 9.7 (‐21.8 to 41.2) |
Comparison 2 Pregnancy prevention curriculum versus usual sex education, Outcome 3 Outcomes by age 20 (women, 4.5 years postprogram).
| Study | Outcome | N (ever had sex) | Experimental | Control | Reported adjusted beta ± SE | Reported P |
| Taylor 2014 | Been pregnant or caused pregnancy | 129 | 6.3% (5) | 4.4% (2) | 0.27 ± 2.99 | NS |
| Taylor 2014 | Condom use (any) | 129 | 54.2% (39) | 36.7% (11) | 0.98 ± 0.37 | < 0.01 |
Comparison 3 Pregnancy prevention program versus usual life skills program, Outcome 1 Dichotomous outcomes at 4‐month follow‐up.
| Study | Outcome | N | Experimental | Control | Reported adjusted beta ± SE | Reported P |
| Taylor 2014 | Condom use consistency (4‐point scale) | 129 | 2.34 ± 1.29 | 2.66 ± 1.28 | ‐0.25 ± 0.21 | NS |
| Taylor 2014 | Attitude toward teen pregnancy (pro) | 679 | 2.26 ± 0.82 | 2.45 ± 0.85 | ‐0.13 ± 0.13 | NS |
| Taylor 2014 | Attitude toward teen pregnancy (con) | 679 | 3.81 ± 0.87 | 3.83 ± 0.93 | 0.01 ± 0.09 | NS |
Comparison 3 Pregnancy prevention program versus usual life skills program, Outcome 2 Scale outcomes at 4‐month follow‐up.
| Study | Gender | N | Reported adjusted |
| Graham 2002 | Girls (non‐virgins) | 415 | ‐8.0 (‐20.8 to 4.7) |
| Graham 2002 | Boys (non‐virgins) | 400 | ‐0.1 (‐8.9 to 8.7) |
Comparison 4 Sex education: EC unit versus no EC unit, Outcome 1 Used EC by 6 months.
| Study | Outcome | Gender | N | Reported adjusted | Reported P |
| Graham 2002 | Correct time limit for hormonal EC | Girls | 1482 | 20.4 (10.4 to 30.4) | < 0.01 |
| Graham 2002 | _ | Boys | 1581 | 15.9 (6.5 to 25.3) | < 0.01 |
| Graham 2002 | Correct time limit for use of intrauterine contraception (IUC) as EC | Girls | 1462 | 10.7 (0.4 to 21.0) | 0.04 |
| Graham 2002 | _ | Boys | 1592 | 4.2 (0.7 to 7.7) | 0.02 |
Comparison 4 Sex education: EC unit versus no EC unit, Outcome 2 EC knowledge at 6 months.
| Study | Outcome | Comparison | N | Reported adjusted OR (95% CI) |
| Walker 2006 | Condom use at first sex | HIV prevention vs usual sex education | 3024 | 1.18 (0.80 to 1.74) |
| Walker 2006 | _ | HIV prevention + EC unit vs usual sex education | 3024 | 1.11 (0.76 to 1.64) |
| Walker 2006 | Condom use at last sex | HIV prevention vs usual sex education | 2985 | 1.14 (0.77 to 1.68) |
| Walker 2006 | _ | HIV prevention + EC unit vs usual sex education | 2985 | 1.05 (0.71 to 1.54) |
Comparison 5 HIV prevention ± EC unit versus usual sex education, Outcome 1 Condom use by 1 year.
| Study | Comparison | N | Reported adjusted OR (95% CI) |
| Walker 2006 | HIV prevention vs usual sex education | 2871 | 1.22 (0.74 to 2.02) |
| Walker 2006 | HIV prevention + EC unit vs usual sex education | 2871 | 2.16 (1.30 to 3.59) |
Comparison 5 HIV prevention ± EC unit versus usual sex education, Outcome 2 Used EC by 1 year.
| Study | Comparison | N | Reported adjusted OR (95% CI) |
| Walker 2006 | HIV prevention vs usual sex education | 16,129 | 1.06 (0.90 to 1.26) |
| Walker 2006 | HIV prevention + EC unit vs usual sex education | 16,129 | 2.82 (2.36 to 3.37) |
Comparison 5 HIV prevention ± EC unit versus usual sex education, Outcome 3 Knowlege of EC at 1 year.
Comparison 6 Curriculum for HIV and pregnancy prevention versus usual sex education, Outcome 1 OC use with last sex.
Comparison 6 Curriculum for HIV and pregnancy prevention versus usual sex education, Outcome 2 Condom use with last sex.
Comparison 6 Curriculum for HIV and pregnancy prevention versus usual sex education, Outcome 3 Ever pregnant or caused pregnancy (reported no pregnancy at pretest).
Comparison 6 Curriculum for HIV and pregnancy prevention versus usual sex education, Outcome 4 Ever pregnant or caused pregnancy (sexually experienced).
| Study | Assessment | Intervention | Intervention | Control | Control | Reported P |
| Kirby 1997 | 5‐month post‐test | 0.59 | 740 | 0.07 | 720 | < 0.001 |
| Kirby 1997 | 17‐month follow‐up | 0.89 | 772 | 0.53 | 757 | < 0.001 |
Comparison 6 Curriculum for HIV and pregnancy prevention versus usual sex education, Outcome 5 Knowledge of HIV and pregnancy prevention.
| Study | Outcome | Assessment | Intervention | Control | Reported |
| Stephenson 2008 | No unintended pregnancy | 18 months after intervention | 97.7% (1584) | 96.7% (1221) | 1.40 (0.97 to 2.02) |
| Stephenson 2008 | Ever had pregnancy | 54 months after baseline | 7.7% (103) | 10% (93) | 0.62 (0.42 to 0.91) |
| Stephenson 2008 | Ever had unwanted pregnancy | 54 months after baseline | 6.7% (91) | 7.6% (71) | 0.69 (0.44 to 1.07) |
| Stephenson 2008 | Ever had an abortion | 54 months after baseline | 3.9% (53) | 5.1% (48) | 0.56 (0.31 to 1.02) |
Comparison 7 Pregnancy and STI prevention education: peer‐led versus teacher‐led education, Outcome 1 Pregnancy self‐reported (females).
| Study | Outcome | Assessment | Intervention | Control | Reported adjusted OR (95% CI) |
| Stephenson 2008 | Abortion | By age 20 | 5.0% (110), 4.0 to 6.3 | 5.0% (113), 4.0 to 6.4 | 1.07 (0.80 to 1.42) |
| Stephenson 2008 | Live birth | By age 20.5 | 7.5% (178), 5.9 to 9.6 | 10.6% (237), 6.8 to 16.1 | 0.77 (0.51 to 1.15) |
Comparison 7 Pregnancy and STI prevention education: peer‐led versus teacher‐led education, Outcome 2 Abortion or live birth records by age 20.
| Study | Outcome | Assessment | Intervention | Control | Reported adjusted OR (95% CI) |
| Stephenson 2008 | Use at first sex | 6 months after intervention | 79% (182) | 76% (164) | 1.14 (0.81 to 1.62) |
| Stephenson 2008 | Use at first sex | 18 months after intervention | 82% (496) | 82% (450) | 0.90 (0.73 to 1.11) |
| Stephenson 2008 | Use at first sex (≥ age 19) | 54 months after baseline | 86% (854) | 84% (631) | 1.07 (0.88 to 1.31) |
| Stephenson 2008 | Use at most recent sex | 18 months after intervention | 85% (431) | 83% (341) | 1.06 (0.70 to 1.63) |
| Stephenson 2008 | Use at most recent sex | 54 months after baseline | 94% (873) | 90% (577) | 1.43 (0.94 to 2.18) [weighted for non‐response] |
Comparison 7 Pregnancy and STI prevention education: peer‐led versus teacher‐led education, Outcome 3 Contraception use for girls.
| Study | Outcome | Assessment | Intervention | Control | Reported adjusted OR (95% CI) |
| Stephenson 2008 | Use at first sex | 6 months after intervention | 86% (204) | 81% (156) | 1.63 (0.99 to 2.67) |
| Stephenson 2008 | Use at first sex | 18 months after intervention | 84% (443) | 85% (367) | 1.01 (0.68 to 1.49) |
| Stephenson 2008 | Use at first sex (≥ age 19) | 54 months after baseline | 87% (650) | 88% (509) | 1.04 (0.65 to 1.68) |
| Stephenson 2008 | Use at most recent sex | 18 months after intervention | 86% (301) | 87% (229) | 1.06 (0.70 to 1.63) |
| Stephenson 2008 | Use at most recent sex | 54 months after baseline | 91% (227) | 94% (156) | 0.61 (0.25 to 1.46) [weighted for non‐response] |
Comparison 7 Pregnancy and STI prevention education: peer‐led versus teacher‐led education, Outcome 4 Contraception use for boys.
| Study | Outcome | Assessment | Intervention | Control | Reported adjusted OR (95% CI) |
| Stephenson 2008 | Use at first sex | 6 months after intervention | 73% (168) | 74% (159) | 0.89 (0.58 to 1.34) |
| Stephenson 2008 | Use at first sex | 18 months after intervention | 75% (602) | 76% (420) | 0.86 (0.67 to 1.12) |
| Stephenson 2008 | Use at first sex (≥ age 19) | 54 months after baseline | 77% (757) | 78% (581) | 0.89 (0.70 to 1.13) |
| Stephenson 2008 | Use at most recent sex | 18 months after intervention | 62% (318) | 62% (255) | 0.96 (0.74 to 1.25) |
| Stephenson 2008 | Use at most recent sex | 54 months after baseline | 52% (483) | 52% (325) | 0.90 (0.73 to 1.11) |
Comparison 7 Pregnancy and STI prevention education: peer‐led versus teacher‐led education, Outcome 5 Condom use for girls.
| Study | Outcome | Assessment | Intervention | Control | Reported adjusted OR (95% CI) |
| Stephenson 2008 | Use at first sex | 6 months after intervention | 83% (198) | 79% (152) | 1.42 (0.80 to 2.53) |
| Stephenson 2008 | Use at first sex | 18 months after intervention | 80% (420) | 81% (352) | 0.95 (0.62 to 1.43) |
| Stephenson 2008 | Use at first sex (≥ age 19) | 54 months after baseline | 80% (599) | 82% (477) | 0.97 (0.65 to 1.45) |
| Stephenson 2008 | Use at most recent sex | 18 months after intervention | 71% (251) | 77% (203) | 0.69 (0.47 to 1.01) |
| Stephenson 2008 | Use at most recent sex | 54 months after baseline | 62% (154) | 67% (111) | 0.83 (0.44 to 1.58) [weighted for non‐response] |
Comparison 7 Pregnancy and STI prevention education: peer‐led versus teacher‐led education, Outcome 6 Condom use for boys.
| Study | Gender | Assessment | Intervention | Control | Reported adjusted OR (95% CI) |
| Stephenson 2008 | Girls | 6 months after intervention | 44% (883) | 42% (685) | 1.13 (0.85 to 1.50) |
| Stephenson 2008 | _ | 18 months after intervention | 67% (1195) | 65% (905) | 1.08 (0.78 to 1.50) |
| Stephenson 2008 | _ | 54 months after baseline | 79% (1089) | 79% (756) | 0.93 (0.66 to 1.32) [weighted for non‐reponse] |
| Stephenson 2008 | Boys | 6 months after intervention | 22% (457) | 23% (399) | 0.92 (0.65 to 1.28) |
| Stephenson 2008 | _ | 18 months after intervention | 37% (674) | 33% (456) | 1.25 (0.89 to 1.75) |
| Stephenson 2008 | _ | 54 months after baseline | 46% (477) | 43% (315) | 1.11 (0.86 to 1.45) [weighted for non‐response] |
Comparison 7 Pregnancy and STI prevention education: peer‐led versus teacher‐led education, Outcome 7 Knowledge of EC pill timing.
| Study | Gender | Assessment | Intervention | Control | Reported adjusted OR (95% CI) |
| Stephenson 2008 | Girls | 6 months after intervention | 1919 | 1554 | 1.15 (0.92 to 1.44) |
| Stephenson 2008 | _ | 18 months after intervention | 1700 | 1264 | 1.19 (0.98 to 1.45) |
| Stephenson 2008 | Boys | 6 months after intervention | 1964 | 1589 | 1.15 (0.95 to 1.39) |
| Stephenson 2008 | _ | 18 months after intervention | 1720 | 1235 | 1.09 (0.92 to 1.29) |
Comparison 7 Pregnancy and STI prevention education: peer‐led versus teacher‐led education, Outcome 8 Positive attitude about condom use.
| Study | Outcome | Assessment | N | Reported adjusted OR ± SE | Reported P |
| Coyle 2001 | Use of effective protection against pregnancy at last sex (condom, OCs, or both) | After 9th‐grade lessons (7 months after baseline) | 998 | 1.62 ± 0.22 | 0.03 |
| Coyle 2001 | _ | After 10th‐grade lessons (19 months after baseline) | _ | 1.40 (no SE reported) | 0.38 |
| Coyle 2001 | _ | 12 months after year 2 (31 months after baseline) | 549 | 1.76 ± 0.29 | 0.05 |
Comparison 8 Curriculum to prevent pregnancy, HIV, and STI versus standard sex education, Outcome 1 Effective protection against pregnancy.
| Study | Outcome | Assessment | N | Reported adjusted effect ± SE | Reported P |
| Coyle 2001 | Condom use at first sex (initiators only) | After 9th‐grade lessons (7 months after baseline) | 285 | OR 0.68 ± 0.48 | 0.42 |
| Coyle 2001 | _ | After 10th‐grade lessons (19 months after baseline) | _ | OR 1.23 (no SE reported) | 0.52 |
| Coyle 2001 | _ | 12 months after year 2 (31 months after baseline) | 733 | OR 1.44 ± 0.27 | 0.17 |
| Coyle 2001 | Condom use at last sex | After 9th‐grade lessons | 1018 | OR 1.91 ± 0.27 | 0.02 |
| Coyle 2001 | _ | After 10th‐grade lessons | _ | OR 1.51 (no SE reported) | 0.26 |
| Coyle 2001 | _ | 12 months after year 2 | 549 | OR 1.68 ± 0.25 | 0.04 |
| Coyle 2001 | Frequency of sex without condom in past 3 months | After 9th‐grade lessons | 963 | Ratio of adjusted means (RM) 0.50 ± 0.31 | 0.03 |
| Coyle 2001 | _ | After 10th‐grade lessons | _ | RM 0.69 (no SE reported) | 0.14 |
| Coyle 2001 | _ | 12 months after year 2 | 1371 | RM 0.63 ± 0.23 | 0.05 |
Comparison 8 Curriculum to prevent pregnancy, HIV, and STI versus standard sex education, Outcome 2 Condom use.
| Study | Assessment | N | Reported adjusted MD ± SE | Reported P |
| Coyle 2001 | After 9th‐grade lessons (7 months after baseline) | 3510 | 0.10 ± 0.03 | < 0.01 |
| Coyle 2001 | After 10th‐grade lessons (19 months after baseline) | _ | 0.07 (no SE reported) | < 0.01 |
| Coyle 2001 | 12 months after year 2 (31 months after baseline) | 3751 | 0.07 ± 0.02 | 0.01 |
Comparison 8 Curriculum to prevent pregnancy, HIV, and STI versus standard sex education, Outcome 3 Attitudes toward condoms.
| Study | Assessment (post‐program) | N | Reported adjusted OR (95% CI) | Reported P |
| Coyle 2006 | 5 months post‐program | 308 | 0.61 (0.33 to 1.12) | 0.11 |
| Coyle 2006 | 11 months post‐program | _ | 1.15 (no CI reported) | 0.66 |
| Coyle 2006 | 17 months post‐program | _ | 0.84 (no CI reported) | 0.61 |
Comparison 9 Curriculum to prevent HIV, STI, and pregnancy versus usual prevention activities (in alternative schools), Outcome 1 Pregnancy (self report).
| Study | Assessment | N | Reported adjusted OR (95% CI) |
| Coyle 2006 | 5 months post‐program | 527 | 1.15 (0.78 to 1.70) |
| Coyle 2006 | 11 months post‐program | 460 | 1.12 (0.74 to 1.66) |
| Coyle 2006 | 17 months post‐program | 417 | 0.77 (0.49 to 1.23) |
Comparison 9 Curriculum to prevent HIV, STI, and pregnancy versus usual prevention activities (in alternative schools), Outcome 2 Effective pregnancy prevention at last sex.
| Study | Assessment | N | Reported adjusted OR (95% CI) |
| Coyle 2006 | 5 months post‐program | 469 | 2.12 (1.24 to 3.56) |
| Coyle 2006 | 11 months post‐program | 386 | 0.88 (0.50 to 1.55) |
| Coyle 2006 | 17 months post‐program | 359 | 1.00 (0.49 to 2.02) |
Comparison 9 Curriculum to prevent HIV, STI, and pregnancy versus usual prevention activities (in alternative schools), Outcome 3 Condom use at last sex.
| Study | Assessment | N | Reported adjusted MD ± SE | Reported P |
| Coyle 2006 | 5 months post‐program | 412 | ‐1.09 ± 0.36 | 0.002 |
| Coyle 2006 | 11 months post‐program | 328 | 0.18 ± 0.34 | 0.6 |
| Coyle 2006 | 17 months post‐program | 289 | 0.38 ± 0.39 | 0.33 |
Comparison 9 Curriculum to prevent HIV, STI, and pregnancy versus usual prevention activities (in alternative schools), Outcome 4 Frequency of sex without condom use in past 3 months.
| Study | Assessment | N | Reported adjusted MD ± SE | Reported P |
| Coyle 2006 | 5 months post‐program | 532 | 0.055 ± 0.028 | 0.05 |
| Coyle 2006 | 11 months post‐program | 449 | 0.026 ± 0.029 | 0.4 |
| Coyle 2006 | 17 months post‐program | 411 | 0.060 ± 0.030 | 0.04 |
Comparison 9 Curriculum to prevent HIV, STI, and pregnancy versus usual prevention activities (in alternative schools), Outcome 5 Condom knowledge.
| Study | Assessment | N | Reported adjusted MD ± SE | Reported P |
| Coyle 2006 | 5 months post‐program | 527 | 0.086 ± 0.061 | 0.16 |
| Coyle 2006 | 11 months post‐program | 451 | 0.035 ± 0.052 | 0.5 |
| Coyle 2006 | 17 months post‐program | 413 | ‐0.044 ± 0.066 | 0.5 |
Comparison 9 Curriculum to prevent HIV, STI, and pregnancy versus usual prevention activities (in alternative schools), Outcome 6 General attitudes toward condoms.
| Study | Outcome | Assessment | N | Reported adjusted risk ratio (95% CI) |
| Tortolero 2010 | Condom use at last vaginal sex | 24 months after baseline (3 months postprogram) | 166 | 1.04 (0.87 to 1.25) |
| Tortolero 2010 | Vaginal sex without condom in last 3 months | 24 months after baseline (3 months postprogram) | 166 | 0.92 (0.71 to 1.19) |
| Tortolero 2010 | Vaginal sex without effective pregnancy prevention in last 3 months | 24 months after baseline (3 months postprogram) | 162 | 0.83 (0.51 to 1.35) |
Comparison 10 HIV, STI, and pregnancy prevention versus usual health classes, Outcome 1 Contraception use.
| Study | Assessment | N | Intervention | Comparison | Reported difference in adjusted mean | Reported P |
| Tortolero 2010 | 24 months after baseline (3 months postprogram) | 893 | 2.41 ± 0.79 | 2.25 ± 0.95 | 0.16 | < 0.01 |
Comparison 10 HIV, STI, and pregnancy prevention versus usual health classes, Outcome 2 Condom knowledge.
| Study | Comparison | Assessment | N | Reported adjusted OR (95% CI) |
| Markham 2012 | Risk avoidance vs control | 3 months (9th grade) | 843 | 0.70 (0.52 to 0.93) |
| Markham 2012 | _ | > 15 months (10th grade) | 777 | 0.61 (0.45 to 0.85) |
| Markham 2012 | Risk reduction vs control | 3 months (9th grade) | 725 | 0.67 (0.47 to 0.96) |
| Markham 2012 | _ | > 15 months (10th grade) | 677 | 0.71 (0.38 to 1.34) |
Comparison 11 Education for sexual risk avoidance versus risk reduction versus usual health education, Outcome 1 Unprotected sex (no condom) at last vaginal sex.
| Study | Comparison | Assessment | N | Reported adjusted OR (95% CI) |
| Markham 2012 | Risk avoidance vs control | 3 months (9th grade) | 741 | 0.97 (0.74 to 1.28) |
| Markham 2012 | _ | > 15 months (10th grade) | 638 | 0.66 (0.44 to 1.00) |
| Markham 2012 | Risk reduction vs control | 3 months (9th grade) | 619 | 0.59 (0.36 to 0.95) |
| Markham 2012 | _ | > 15 months (10th grade) | 550 | 0.98 (0.66 to 1.47) |
Comparison 11 Education for sexual risk avoidance versus risk reduction versus usual health education, Outcome 2 Vaginal sex without condom in last 3 months.
| Study | Comparison | Assessment | N | Reported adjusted MD | Reported P value |
| Markham 2012 | Risk avoidance vs control | 3 months (9th grade) | 894 | 0.00 | NS |
| Markham 2012 | _ | > 15 months (10th grade) | 833 | 0.03 | NS |
| Markham 2012 | Risk reduction vs control | 3 months (9th grade) | 780 | 0.09 | < 0.01 |
| Markham 2012 | _ | > 15 months (10th grade) | 717 | 0.10 | < 0.01 |
Comparison 11 Education for sexual risk avoidance versus risk reduction versus usual health education, Outcome 3 General condom knowledge.
| Interactive program on HIV/STI and pregnancy prevention compared with usual sex or health education for improving contraceptive use | ||||
| Patient or population: middle or high school students with need for contraceptive information Settings: school classroom Intervention: HIV/STI and pregnancy prevention Comparison: usual sex or health education | ||||
| Outcomes | Reported relative effect | Clusters; participants | Quality of evidence | Intervention; |
| Use of effective contraceptive during last sex: after year 1; 12 months after year 2 | Adjusted OR ± SE: 1.62 ± 0.22; 1.76 ± 0.29 | 20 schoolsa; 3869 students | ⊕⊕⊕⊝ | Multifaceted, 20‐lesson program vs standard HIV prevention (5 sessions + activities) 9th and 10th grades |
| Condom use at last sex: after year 1; 12 months after year 2 | Adjusted OR ± SE: 1.91 ± 0.27; 1.68 ± 0.25 | |||
| Frequency of sex without condom in last 3 months: 12 months after year 2 | Ratio of adjusted means ± SE: | |||
| No condom use at last vaginal sex (3 months) | OR 0.67 (0.47 to 0.96) | 15 schoolsa; 1742 students | ⊕⊕⊕⊝ | Sexual risk reduction (abstinence until older), 24 sessions vs usual health education; 7th and 8th grades |
| Vaginal sex without condom in past 3 months (3 months) | OR 0.59 (0.36 to 0.95) | |||
| No condom use at last vaginal sex: 3 months; 15 months | ORs: 0.70 (0.52 to 0.93); 0.61 (0.45 to 0.85) | Sexual risk avoidance (abstinence until marriage), 24 sessions vs usual health education; 7th and 8th grades | ||
| Oral contraceptive use during last sex (17 months) | OR 0.57 (0.36 to 0.91) | 102 middle‐school classesb; 2110 students | ⊕⊕⊕⊝ | Peer‐led interactive prevention (8 sessions) vs didactic teacher‐led sex education; 7th grade |
| CI: Confidence interval; MD = mean difference; OR: Odds Ratio; SE = standard error | ||||
| GRADE Working Group grade of evidence | ||||
| aRandomized schools | ||||
| Study | Curriculum or | Provider | Training for | Assessed adherence to protocol | Assessed intervention receipt | Fidelity |
| Pregnancy prevention | ||||||
| 14 sessions (50‐minute) for cognitive and behavioral training | Graduate students, 3 to 4 years counseling experience; not with teens regarding sex | _ | _ | Sessions involved problem solving, role play, rehearsal | 3 | |
| Resource pack of 20 lessons, piloted twice and revised; pilot‐test had evaluation with teachers and students | Classroom teachers | 5 days | Process evaluation: lesson observation (lessons covered; who led sessions) | Interaction on video with discussion; how to obtain condoms, practice use | 5 | |
| 12 weekly lessons with topics and activities; developed with formative research | 2 pairs, young, male and female trained facilitators | _ | _ | Lessons were interactive (role play, discussions, debates, videos) | 3 | |
| Emergency contraception | ||||||
| 1 EC lesson from resource for schools | Teachers | 2‐hour training for teachers to improve skill and knowledge; trainer was investigator training in family planning | _ | Lesson had scenario activity and quiz on EC (latter replaced role play after pilot; students had difficulty engaging) | 4 | |
| 15‐week course based on UN guidelines for school programs; 2 hours on EC | Teachers chosen by school | Week‐long (40‐hour) training + 2 hours on EC for schools with EC component | Investigators monitored via phone calls and visits with teachers and direct class observation | Classes included practice in communication, negotiation, and refusal skills; study assessed knowledge of HIV and of EC | 5 | |
| Preventing HIV/STI and pregnancy | ||||||
| Curriculum of 8 sessions over 2 weeks; specific topics and activities for each session | Peer educators hired and trained | 50 hours training to implement | Practiced delivering; had ongoing training and clinical supervision during implementation | Participants practiced skills and applied knowledge in program activities; assessed knowledge and attitudes | 5 | |
| 3 sessions with identified topics and activities; peer‐educators prepared lessons; intervention "standardized as far as possible" | Peer educators: 11th‐grade students Trainers: expertise in sexual health promotion | 2 days: sexual health, participatory learning, classroom management, group facilitation 3 pre‐training sessions for needs assessment + 1 follow‐up on lesson planning | Not specific: Observation for process data (not supervision) | Participatory sessions were interactive; involved practice | 4 | |
| 20 lessons; grades 9 and 10 (10 lessons each year) | School teachers; in‐class peer leaders for selected activities | Teachers had initial training and ongoing technical support | _ | In‐class peer leaders for some activities, role playing; homework (student‐parent, local resources) | 4 | |
| 14‐session curriculum; 9 class lessons and 5 units of service‐learning; pilot‐tested twice | Experienced health educators | Trained to implement; practiced during pilot | _ | Curriculum had experiential activities, e.g., creating posters, role playing, group discussion, guided skill practice. | 4 | |
| 24 lessons (45‐minute) developed with qualitative work and participatory methods | Trained facilitators | _ | _ | Sessions had computer‐based activities with quizzes, serials with on‐line student feedback, discussion | 3 | |
| 24 sessions (12 per year) of 50 min each; based on existing middle school program | Hired for program; most were African American or Hispanic with college degrees; experienced working with adolescents | 5‐day training; skilled trainers modeled lessons, provided teaching practice | Technical support during implementation | Assessed knowledge and self efficacy about sex and condom use | 5 | |
| Study | Interventions | Special intervention sessions | Participants | Sample size | Location |
| Pregnancy prevention | |||||
| Cognitive and behavioral training vs assessment only | 14; 50 minutes each | Sophomores (2nd year high school) | 1 school; 36 students | USA | |
| Active learning + skill development vs usual sex education | 20; 10 in each of 2 years | 13 to 15 years old | 25 schools; 7616 students completed baseline surveys | Scotland | |
| Interactive program + usual life skills + media messages vs usual life skills and media messages | 12; weekly | Grade 8 (1st year high school) | 16 schools; 816 students completed baseline surveys | South Africa | |
| Emergency contraception | |||||
| Usual sex education + EC unit vs usual sex education | 1 on EC | Year 10 | 24 secondary schools; 3234 students completed baseline survey | England | |
| HIV prevention education + EC unit or HIV prevention education vs usual sex education | HIV prevention 30 hours over 15 weeks; EC 1 at 2 hours | Grade 10 | 40 schools; 10,954 students at baseline | Mexico | |
| Preventing HIV/STI and pregnancy | |||||
| Peer‐led interactive curriculum + didactic sex education vs didactic sex education | 8; over 2 weeks | Grade 7 | 102 classes (6 middle schools); approximately 2110 students completed baseline surveys | USA | |
| Peer‐led vs teacher‐led sex education | 3; 1 hour each | Grade 8 (age 13 to 14 years) | 27 schools; 8766 students at baseline | UK | |
| Multicomponent program vs standard HIV prevention curriculum | 20; 10 in each of 2 years | Grades 9 & 10 | 20 schools; 3869 students completed baseline surveys | USA | |
| Skills‐based curriculum + service learning vs usual prevention activities | 14 (9 + 5 service); over 5 to 7 weeks | Alternative day school (age 14 to 18+ years) | 24 schools; 988 students completed baseline surveys | USA | |
| Risk reduction vs usual health education | 24; 12 in each of 2 years | Grades 7 & 8 | 10 schools; 1307 students completed baseline surveys | USA | |
| Risk avoidance or risk reduction vs usual health education | 24; 12 in each of 2 years | Grades 7 & 8 | 15 schools; 1742 students completed baseline survey | USA | |
| EC: emergency contraception | |||||
| Study | Intervention fidelity < 4 items | Randomization; allocation concealment | Follow‐up period | Analysis | Loss > 20% | Evidence qualitya | Evidence of effectiveness |
| Pregnancy prevention | |||||||
| _ | _ | _ | ‐1 | ‐1 | Low | None | |
| ‐1 | ‐1 | _ | _ | _ | Low | Contraception use (6 months); unclear definitions | |
| ‐1 | _ | _ | ‐1 | ‐1 | Very low | Condom use, any (4 months) | |
| Emergency contraception | |||||||
| _ | _ | _ | ‐1 | _ | Moderate | Knew time limits for hormonal EC and for IUC as EC (6 months) | |
| _ | _ | _ | ‐1 | ‐1 | Low | HIV + EC group: used EC and had EC knowledge (1 year) | |
| Preventing HIV/STI and pregnancy | |||||||
| _ | _ | _ | ‐1 | _ | Moderate | OC use with last sex (17 months)b; mean knowledge increase (5 & 17 months) | |
| ‐1 | _ | _ | ‐1 | ‐1 | Very low | Ever pregnant, self report (54 months) | |
| _ | _ | _ | _ | ‐1 | Moderate | After year 1 & 12 months after year 2: less frequent sex without condom in past 3 months; condom use at last sex; use of effective contraceptive at last sex | |
| _ | _ | _ | ‐1 | ‐1 | Low | 5 months after program: less frequent sex without condom in past 3 months; condom use at last sex 5 & 17 months: | |
| ‐1 | _ | _ | ‐1 | ‐1 | Very low | Condom knowledge (24 months after baseline) | |
| _ | _ | _ | _ | ‐1 | Moderate | Risk avoidance group: Risk reduction group: sex without condom in last 3 months (3 months); | |
| EC: emergency contraception aDowngraded (‐1) for the following: (1) intervention fidelity < 4 criteria; (2) inadequate randomization sequence generation or allocation concealment, or no information on either; (3) analysis for primary outcome based on non‐randomized subsample, or analysis not adjusted for clustering; (4) follow‐up < 6 months for contraceptive use or < 12 months for pregnancy; (5) loss to follow‐up > 20% | |||||||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Contraceptive use and attitudes at 6 months Show forest plot | Other data | No numeric data | ||
| 2 Contraception knowledge at post‐test Show forest plot | Other data | No numeric data | ||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Pregnancy and oral contraceptive use at 6 months postprogram (24 months) Show forest plot | Other data | No numeric data | ||
| 2 Condom use at 6 months postprogram (24 months) Show forest plot | Other data | No numeric data | ||
| 3 Outcomes by age 20 (women, 4.5 years postprogram) Show forest plot | Other data | No numeric data | ||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Dichotomous outcomes at 4‐month follow‐up Show forest plot | Other data | No numeric data | ||
| 2 Scale outcomes at 4‐month follow‐up Show forest plot | Other data | No numeric data | ||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Used EC by 6 months Show forest plot | Other data | No numeric data | ||
| 2 EC knowledge at 6 months Show forest plot | Other data | No numeric data | ||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Condom use by 1 year Show forest plot | Other data | No numeric data | ||
| 2 Used EC by 1 year Show forest plot | Other data | No numeric data | ||
| 3 Knowlege of EC at 1 year Show forest plot | Other data | No numeric data | ||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 OC use with last sex Show forest plot | 1 | Odds Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| 1.1 5‐month post‐test | 1 | 229 | Odds Ratio (M‐H, Fixed, 95% CI) | 0.73 [0.42, 1.27] |
| 1.2 17‐month follow‐up | 1 | 354 | Odds Ratio (M‐H, Fixed, 95% CI) | 0.57 [0.36, 0.91] |
| 2 Condom use with last sex Show forest plot | 1 | Odds Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| 2.1 5‐month post‐test | 1 | 233 | Odds Ratio (M‐H, Fixed, 95% CI) | 0.78 [0.46, 1.34] |
| 2.2 17‐month follow‐up | 1 | 353 | Odds Ratio (M‐H, Fixed, 95% CI) | 0.76 [0.49, 1.18] |
| 3 Ever pregnant or caused pregnancy (reported no pregnancy at pretest) Show forest plot | 1 | Odds Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| 3.1 5‐month post‐test | 1 | 1402 | Odds Ratio (M‐H, Fixed, 95% CI) | 1.53 [0.66, 3.55] |
| 3.2 17‐month follow‐up | 1 | 1482 | Odds Ratio (M‐H, Fixed, 95% CI) | 0.82 [0.34, 1.99] |
| 4 Ever pregnant or caused pregnancy (sexually experienced) Show forest plot | 1 | Odds Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| 4.1 5‐month post‐test | 1 | 201 | Odds Ratio (M‐H, Fixed, 95% CI) | 1.25 [0.46, 3.36] |
| 4.2 17‐month follow‐up | 1 | 312 | Odds Ratio (M‐H, Fixed, 95% CI) | 0.85 [0.33, 2.14] |
| 5 Knowledge of HIV and pregnancy prevention Show forest plot | Other data | No numeric data | ||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Pregnancy self‐reported (females) Show forest plot | Other data | No numeric data | ||
| 2 Abortion or live birth records by age 20 Show forest plot | Other data | No numeric data | ||
| 3 Contraception use for girls Show forest plot | Other data | No numeric data | ||
| 4 Contraception use for boys Show forest plot | Other data | No numeric data | ||
| 5 Condom use for girls Show forest plot | Other data | No numeric data | ||
| 6 Condom use for boys Show forest plot | Other data | No numeric data | ||
| 7 Knowledge of EC pill timing Show forest plot | Other data | No numeric data | ||
| 8 Positive attitude about condom use Show forest plot | Other data | No numeric data | ||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Effective protection against pregnancy Show forest plot | Other data | No numeric data | ||
| 2 Condom use Show forest plot | Other data | No numeric data | ||
| 3 Attitudes toward condoms Show forest plot | Other data | No numeric data | ||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Pregnancy (self report) Show forest plot | Other data | No numeric data | ||
| 2 Effective pregnancy prevention at last sex Show forest plot | Other data | No numeric data | ||
| 3 Condom use at last sex Show forest plot | Other data | No numeric data | ||
| 4 Frequency of sex without condom use in past 3 months Show forest plot | Other data | No numeric data | ||
| 5 Condom knowledge Show forest plot | Other data | No numeric data | ||
| 6 General attitudes toward condoms Show forest plot | Other data | No numeric data | ||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Contraception use Show forest plot | Other data | No numeric data | ||
| 2 Condom knowledge Show forest plot | Other data | No numeric data | ||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Unprotected sex (no condom) at last vaginal sex Show forest plot | Other data | No numeric data | ||
| 2 Vaginal sex without condom in last 3 months Show forest plot | Other data | No numeric data | ||
| 3 General condom knowledge Show forest plot | Other data | No numeric data | ||
