Reducing Caesarean Deliveries: Trends and Analysis of Risk Factors over a Decade

This paper a retrospective analysis of Caesarean deliveries (CD) between 28 and 42 weeks of gestation over 11 years’ revealed strategies that reduced the rate of Caesarian deliveries. The trend and risk factor analysis was done for singleton and twin gestations. Segmented regression analysis was performed for trend analysis between the two time periods. Multiple Logistic regression analysis and Generalized Estimating Equations regression analysis was done for the risk factor analysis of singleton and twin deliveries respectively. The increasing and decreasing trend of CDs were presented here. A significant change in trend for CD: a steady rise (10.2%) from 20.9% in 2000 to 31.2% in 2006, followed by a slow rise(2.8%) to 33% from 31.2% between 2006 and 2010, was observed when simple interventions to reduce CD rate was instituted. The trend analysis of successful trial of labour after CD was also done. This study concludes that the simple interventions can be instituted to decrease caesarean delivery rates. Multifaceted strategies will be effective in reducing CD rates. Preterm births constitute a majority of CD; hence measures to decrease preterm birth should be a priority.


Introduction
Caesarean delivery (CD) is a life saving procedure and 18.5 millions CDs are performed yearly worldwide [1].Rates between 5% and 10% have been recommended by WHO for better neonatal outcomes [2][3].The CD rate in the United States was 20.7% in 1996 and rose to 32.7% in 2010 [4].In Australia, it had increased from 21.8% in 1999 to 32.3% in 2013 [5].China showed a steep increase of CD from 19% to 58% [6].Increasing trends were noted in low income countries such as Tanzania, Latin America and in Africa as well [7][8].CD rates were more than 40% in many Indian states (9).CD rates have skyrocketed all over the world even though; a higher CD rate was not associated with reduction in maternal and newborn mortality rates [10][11].
The risk of CD increases with increasing maternal age, extreme neonatal birth weights and high risk pregnancy [12][13].The increasing safety of anesthesia, surgical skills, suture material, makes women accept elective CD easily [14][15].Complications inherent with CD are noted to be close to 12% [16][17].
A prior CD has a 1% risk of uterine rupture as well, that contributes up to 10% of maternal deaths [18].The whole world is looking at ways to contain this exploding of CDs (keeping the minimum CD rate at 15% as recommended by the WHO) (1).

Data Source
Data was collected from the Labour room register of the Department of Obstetrics and Gynecology, Christian Medical College Vellore.These records are maintained by the Senior Staff Nurse in charge of Labour Room and counterchecked every month by the Senior Doctor in charge of the Obstetric Audit.The data of all women who had CD between 28 and 42 weeks of gestation, from January 2000 to December 2010 were collected by rotational sampling.

IRB and Ethics Committee Approval
The Institutional Review Board of Christian Medical College Vellore waived the informed consent.(IRB Min No. 7109 dated 10.03.2010).

Statistical Methods
The records were entered in EPI INFO data sheet (Epiinfo3.5.1, CDC, USA) and analyzed using SPSS (SPSS Statistics for Windows, Version 17.0.Chicago: SPSSInc.) and STATA (StataCorp.2011. Stata Statistical Software: Release 12. College Station, TX: StataCorpLP).Frequencies and percentages were calculated for the categorical variables and mean and standard deviation were calculated estimated for the continuous variables.The trend analysis of CD rate was performed using the time series plot of yearly CD proportions.Segmented regression analysis was used to find the significant difference in the trend of two time periods.Unadjusted and adjusted logistic regression analyses were done to find the risks for CD among singleton deliveries.Generalized Estimating Equation (GEE) analyses were performed to find the risk factors for CD among twin deliveries, considering mother as a cluster.For singleton delivery data analysis, the variables that were significant at 5% level of significance from the univariate analysis were included for multivariate analyses and 20% level of significance for the twin delivery data analyses.Single and multiple line plots were used to present the trend of CD based on the various factors.

Definitions Literacy
Standard of education was grouped separately for the woman and for her husband into: illiterate, including those who were unable to read or write; Primary and Secondary, included those who had a school education of 7 years or less; High school and Higher Secondary, included those who had a school education of 8 years to 12 years; and Degree and above, for those with higher education.

Parity
The number of pregnancies carried to viable gestational age.The women who delivered for the first time were defined as nulliparous women and others as multiparous women.

Infertility
Women who were infertile for more than 1 year.

Hypertensive Disease of Pregnancy
Gestational hypertension included women who had blood pressure greater than or equal to 140/90 mmHg on 2 occasions, 6 hours apart after 20 weeks gestation.Chronic hypertension: If the diagnosis of hypertension predated the pregnancy, or had hypertension diagnosed prior to 20 weeks of gestation.Eclampsia: Hypertension and proteinuria associated with seizures.Pre-Eclampsia: Hypertension associated with proteinuria.

Cardiac Disease
Cardiac disease included all pregnant women with rheumatic or congenital heart disease diagnosed by the Cardiologist, based on echocardiogram and /or other relevant tests.

Body Mass Index (BMI)
BMI was calculated from maternal weight at delivery using the standard formula: [weight (kg)/height (m) 2 ] formula.Women with a BMI below18.5kg/m 2 were classified as underweight, BMI of 18.5-24.9kg/m 2 , was considered normal, those with 25-29.9kg/m 2, over weight and BMI>=30kg/m 2 , obese.Pre pregnancy weight was not available in most of the patients who were booked at various gestational ages for antenatal care and therefore could not be used in the analysis.Gestational weight gain could not be used in the analysis for the same reasons.

Anemia
Included women with a Hemoglobin (Hb)<11g/dL based on WHO definition of anemia.

Diabetes
Diabetes included women with diabetes predating their pregnancy and those with a positive 100 gm 3 hour oral glucose tolerance test with cut-offs at baseline, one, two and three hours following Citation: Tunny Sebastian, Visalakshi Jeyaseelan, Jeyaseelan Lakshmanan, Reeta Vijayaselvi, Ruby Jose (2016) Reducing Caesarean Deliveries: Trends and Analysis of Risk Factors over a Decade.BAOJ Gynaec 1: 003.glucose ingestion.

Oligoamnios
An amniotic fluid index of less than 5cms.

Birth Weight
All babies were weighed within an hour of delivery using 111 Braun electronic weighing scale.The scale is calibrated regularly to maintain accuracy to ±0.5g.

Pre Term
Delivery at a gestational age of less than 37 weeks.

Small for Gestational Age (SGA)
SGA was assigned when a newborn had a birth weight lower than the 10 th centile for the gestational age in weeks.

Large for Gestational Age (LGA)
LGA was assigned when a newborn had a birth weight higher than the 90 th centile for gestational age in weeks.

Descriptive Analyses
There were a total of 30,335 deliveries during the study period, out of which, 8411(27.7%)had CD.Of this, 7943(26.18%)were done on singletons, 459(1.51%)were done on twin gestation and the rest 9(0.03%) on triplets.Among 9 of the CD for twin gestations, the delivery of the second of twin was by CD following vaginal delivery of the first twin.

Trend Analysis
The overall trend of CD was seen to increase steadily from 20.9% in 2000 to 31.2% in 2006, followed by a slower rise to 33.0% in 2010 Table 1.The segmented regression analysis showed a significance change in trends between the two time periods, 2000-2006 and 2007-2010 (P<0.05).
For twin pregnancies, the CD rate rose from 33.3% in 2000 to 65.7% in 2006 and then dropped to 52.5% in 2010 (Fig1).The CD percentage was seen to increase between 2000-2006(5.1% per year, 95%CI: 3.1%-7.0%,P<0.001) and decreased over the period between 2007-2010(7.6%per year, 95%CI: 2.7%-12.6%,P<0.01), however the CD percentage trends was not statistically significantly different between the two time periods (P=0.671).Both nulliparas and multiparas followed the overall trend of CDs.Among the singleton pregnancies, most of the increase in CD rate was contributed to by primary CD which increased from 14.9% to 22.1%, while repeat CD contributed minimal (5.7% to 10.1%) over the same period of time.
The percentages of successful TOLAC were noted to be significantly

Demographic Risk Factors
There were a total of 29,368 singleton women included in the study, the CD rate was 27.0 (7943).When different age groups were considered, i.e. teenaged, 20-29 years and ≥30 years, there were 300 (17%), 5800 (25%) and 1819 (39%) CDs respectively.The adjusted analysis (Table 2) show that mothers who were ≥30 years had a 1.6 (1.5-1.8)times higher risk of CD (P<0.001) and teenage mothers had lower odds of 0.6 (0.5-0.7) of CD as compared to mothers who were 20-29 years (P<0.001).
The parents' education/occupation was significant in the unadjusted analysis, but only mother's education was significant in the adjusted analysis.Women with primary or secondary school education had a 1.2(1.1-1.4) times higher odds of CD as compared to the higher educated women (Degree or above), p<0.01.
Multiparous women who had a previous CD had a higher odds for CD (OR: 23.4,95%CI: 21.1-25.9)P<0.001) in the unadjusted analysis.

Risk Factor Analysis of Cesarean Deliveries among Women With Twin Pregnancies
There were 946 pairs of twin deliveries, of which 459(48.5%) had CD.Most of the women belonged to the 20-29 year age group (74%) as in the singleton groups.Teenage pregnancies constituted 5%; 21% of the women were > 30 years of age.It is noteworthy that 63.6% of CD among twin pregnancies was preterm CDs (thrice that of singletons).
Teenaged women with twin gestations had nearly 3 times higher risk of CD as compared to the 20-29 age group women(P=0.134)(Table 3).Overweight mothers had 1.9(1.2-2.9)times higher risk for CD and obese mothers had 1.6(1.03-2.5)times higher risk of CD as compared with those mothers with normal BMI after  for labour room personnel.The audit and feedback is an effective strategy, known to reduce CD by 13% when used alone and when used along with multifaceted strategy, can be reduced to 27%.Multifaceted strategies were effective and strong in reducing CDrates.The patient's desire for elective CD without an indication was not encouraged and the demand was minimal.Each of the above strategies contributed to reducing CD rate successfully [21].
When CD risks were analysed, increasing maternal age was found to be independently associated with increasing odds of CD that is in keeping with other study findings [13].Other studies have found that CD was associated with social class and nature of employment ( 22).However, in the present study the proxy variables such as education and occupation were not significantly associated with CD.High CD rate was strongly associated with previous CD (OR= 23;, similar to other studies as well [13][14]23].
SGA neonates had higher risk for CD as has been reported in the literature [12][13].In the present study, overweight and obese women had significantly higher risk for CD, as was reported from France.In France, 20% of the increase in CD was due to increase in the age and weight of the women [10,14].Presence of Diabetes and hypertensive diseases were shown to be significantly associated with CD in many studies, however, in our study hypertension increases the risk for CD significantly, while diabetic status failed to show the significance [13][14][24][25].

Limitations
Though this is a large scale study representing 11 years of deliveries from a private referral and teaching hospital, this may not represent the deliveries which are taking place at the Primary Health Centres in the rural area.

Figure 1 :
Figure 1: Trend of CD deliveries among singleton and twin deliveries from 2000 to 2010.