Maternal and foetal medical conditions during pregnancy as determinants of intrapartum stillbirth in public health facilities of Addis Ababa: a case-control study

Introduction globally, intrapartum stillbirth accounts for 1 million deaths of babies annually, representing approximately one-third of global stillbirth toll. Intrapartum stillbirth occurs due to causes ranging from maternal medical and obstetric conditions; access to quality obstetric care services during pregnancy; and types, timing and quality of intrapartum care. Different medical conditions including hypertensive & metabolic disorders, infections and nutritional deficiencies during pregnancy are among risk factors of stillbirth. Ethiopia remains one of the 10 high-burden stillbirth countries with estimated rate of more than 25 per 1000 births. Methods a case-control study using primary data from chart review of medical records of women who experienced intrapartum stillbirth in 23 public health facilities of Addis Ababa during the period July 1, 2010 - June 30, 2015 was conducted. Data was collected from charts of all cases of intrapartum stillbirth meeting the inclusion criteria and randomly selected charts of controls in two to one (2:1) control to case ratio. Results chronic medical conditions including diabetes, cardiac and renal diseases were less prevalent (1%) among the study population whereas only 6% of women experienced hypertensive disorder during the pregnancy in review. Moreover, 6.5% of the study population had HIV infection where being HIV negative was protective against intrapartum stillbirth (aOR 0.37, 95% CI 0.18-0.78). Women with non-cephalic foetal presentation during last ANC visit were three times more at risk of experiencing intrapartum stillbirth whereas singleton pregnancy had strong protective association against intrapartum stillbirth (p<0.05). Conclusion untreated chronic medical conditions, infection, poor monitoring of foetal conditions and multiple pregnancy are among important risk factors for intrapartum stillbirth.


Introduction
Stillbirth is one of the adverse outcomes of pregnancy. The definition of stillbirth can vary from country to country based on clinical and obstetric care protocols. Some literature define stillbirth as a baby born after the 24 th week of pregnancy who did not at any time breathe or show any other sign of life after being completely removed from the mother [1]. For international comparisons, WHO recommends reporting of stillbirth with birthweight of 1000 g or more, 28 weeks' gestation or more, or a body length of 35cm or more, commonly reported as third-trimester stillbirth [2]. Furthermore, foetal death occurring during labour is referred as intrapartum stillbirth [3].
Globally, nearly 2.6 million third trimester stillbirth occurred in 2015.
Notwithstanding the gestational age cut-off for its definition, stillbirth can occur either during antepartum or intrapartum period. Evidence shows that most of stillbirth can be prevented through the correct application of clinical and obstetric skills hence the current high prevalence is unacceptable. Furthermore, approximately 98% of all stillbirth occur in low and middle-income countries (LMIC), nearly 10fold higher than those documented in high-resource settings [4].
Stillbirth classification varies along geographic regions, causes and timing of stillbirth in relationship to labour. The older concept of macerated versus fresh stillbirth roughly corresponds to gross categorisation of antepartum and intrapartum categories, but with the advent of ultrasound and foetal heart rate (FHR) monitoring tools, the timing of the stillbirth in developed countries is generally known, at least approximately [5]. Regardless of the classification challenges, intrapartum stillbirth accounts for one million deaths of babies annually, representing approximately one-third of global stillbirth toll.
These estimates highlight the magnitude of loss of life just minutes and hours prior to birth with devastating social, emotional and epidemiologic consequences [6].
Moreover, literature shows that stillbirth in general and intrapartum stillbirth particularly occurs due to attributable underlying causes ranging from maternal medical and obstetric conditions; access to quality obstetric care services during pregnancy; and types, timing and quality of intrapartum care. Ethiopia remains one of the 10 highburden countries with estimated rate of more than 25 per 1000 births [4]. The Ethiopian Demographic and Health Survey (2011) reported 46 perinatal deaths per 1000 total birth annually where Addis Ababa experienced approximately 30 per 1000 births for the same period [7]. Medical conditions of the mother during the time of each pregnancy can determine pregnancy outcomes. Marshall and Raynor (2014:224) describe different medical conditions including hypertensive, metabolic, endocrine, respiratory, haematological disorders, infections and nutritional deficiencies that can emerge or become aggravated during pregnancy as critical factors that could cause adverse pregnancy outcomes including stillbirth [8]. For instance, of the 20,000 pregnancies that resulted in stillbirth (39% intrapartum stillbirth) in South Africa between 2008-2009, 20% were associated with hypertensive disease that could have been managed to avert the adverse outcomes [9]. Similarly, HIV and syphilis infections are widely believed to have statistically significant associations with stillbirth. For instance, a study from Namibia reported that approximately 26% of cases of stillbirth in the study population had history of HIV infection during their index pregnancies [10]. A study from North-Eastern Ethiopia showed that pregnant women with syphilis infection were three times more likely to develop stillbirth [11]. Many of these risk factors could be screened and managed as part of the standard antenatal care services, making the latter an indispensable public health practice. Accordingly, this study collected data on key maternal medical conditions including hypertension, diabetes, infections, Antenatal Care (ANC) attendance, and foetal condition during the pregnancy in review from the public health facility in Addis Ababa to see if any of these had statistically significant associations with intrapartum stillbirth compared to the livebirth outcomes.

Methods
Study setting and design: this was a case-control study using primary data from chart review of medical records of women who Sampling: all cases of intrapartum stillbirth that occurred in the public health facilities in Addis Ababa were recorded in the maternity registers which is the sampling frame for this study. Given intrapartum stillbirth is a relatively rare phenomenon, this study included all cases of intrapartum stillbirth meeting the inclusion criteria and recorded in the maternity care registers in 20 public health centres and three hospitals between July 1, 2010 -June 30, 2015.
Controls were selected from the same maternity registers which helped as sampling frame in each public health facility using a lottery method and in two to one (2:1) control to case ratio. Therefore, in each facility, two medical charts of women with livebirths were selected for each case of intrapartum stillbirth. On every page of the maternity registers where cases of intrapartum stillbirth were taken, record numbers of women with livebirth were listed and rolled on pieces of paper of which an individual other than the data collector randomly selected the required number of controls.

Results
Socio-demographic characteristics: data was collected on five key socio-demographic variables including age, marital status, gravida, parity and number of children alive for cases whose charts were reviewed. Accordingly, approximately 57% of women who experienced intrapartum stillbirth and 60% who had livebirths reported to be in the age category 25-34 years. The second highest proportion of women in the study population for both intrapartum stillbirth (35.8%) and livebirth (33.6%) were found in the age group 15-24 years. Results from this study showed that proportionally more women in the intrapartum stillbirth category (49.3%) than in the livebirth (37.1%) conceived for the first time. Consistent with the results on gravida, intrapartum stillbirth was proportionally more common among primigravida (60%) compared to those who given birth to up to three children. This study did not reveal any statistically significant differences between intrapartum stillbirth and livebirth categories for women of three and higher birth orders. However, the descriptive results from this study showed that women with one or more alive children were proportionally less likely to experience intrapartum stillbirth compared to women without any child (Table 1).
Maternal medical condition: only 6.3% of women in the intrapartum stillbirth category and 6.1% of women in the livebirth category reportedly had higher blood pressure during the pregnancies in this study. Similarly, prevalence of other common maternal medical conditions including diabetes, cardiac and renal disease were less than 1% for both groups. On the contrary, 90% and 93% cases and controls were HIV negative during the pregnancy in review respectively. Furthermore, approximately 82% of cases against 91% controls tested negative for syphilis among the study population. The prevalence of syphilis was 0.7% and 0.8% among cases and controls respectively. Considerably high amount of data was missing for both cases (17%) and controls (8.4%) which shows poor record keeping practice and limited diagnostic procedures in the public health facilities of Addis Ababa. Results from the current study showed that proportionally more women in the livebirth (91.9%) category than stillbirth (87.7%) were Rh+, which was protective compared to being Rh-ve during pregnancy. Ironically, there were slightly more Rh-ve women in the livebirth category than stillbirth however referring to the larger missing data among stillbirth group (7.7%) than livebirth (2.9%), the protective association of being Rh+ among livebirth category seems justifiable.  (Table 2).

Discussion
This study assessed various risk factors including sociodemographics, maternal medical conditions during the pregnancy in review to determine associations with intrapartum stillbirth.
Intrapartum stillbirth was highly concentrated in 15-34 years without any statistically significant difference between cases and controls.
This finding is comparable with a study from Kenya [13]. Evidence shows that maternal medical conditions including hypertensive, metabolic, endocrine, respiratory, haematological disorders are associated with adverse pregnancy outcomes including stillbirth [8]. Taiwan also showed that multiple gestations had markedly increased the risk of adverse fatal outcomes including stillbirth [29]. A systematic review also indicated that twin pregnancies are high risk that can results in thirteen-fold increase in the rates of stillbirth (Table 3) [30]. What is known about this topic  Hypertensive disorder during pregnancy can cause stillbirth;

Conclusion
 Being HIV infected during pregnancy is a predictor of stillbirth.

What this study adds
 Pregnant women with non-cephalic foetal presentations during last ANC visits of the index pregnancy were three times more at risk of experiencing intrapartum stillbirth;  Women with one or more alive children were proportionally less likely to experience intrapartum stillbirth compared to women without any child.

Competing interests
The authors declare no competing interests.

Authors' contributions
Both authors equally contributed to this study. As part of his PhD thesis, AG led the design, data collection, analysis and drafting of the report for this study. As academic advisor, Prof. Lebitsi Maud Modiba provided ongoing supervision, guidance and reviewed the study report as well as this manuscript.

Acknowledgments
University of South Africa partially funded the PhD research work without which this article wouldn't have been realized. Table 1: key socio-demographic characteristics against intrapartum stillbirth