Risk factors for antepartum stillbirth: a case-control study in Nepal.

Background: Globally, at least 2.65 million stillbirths occur every year, of which more than half are during the antepartum period. The proportion of intrapartum stillbirths has substantially declined with improved obstetric care; however, the number of antepartum stillbirths has not decreased as greatly. Attempts to lower this number may be hampered by an incomplete understanding of the risk factors leading to the majority of antepartum stillbirths. We conducted this study in a tertiary hospital in Nepal to identify the specific risk factors that are associated with antepartum stillbirth in this setting.

Methods: This case-control study was conducted between July 2012 and September 2013. All women who had antepartum stillbirths during this period were included as cases, while 20 % of all women delivering at the hospital were randomly selected and included as referents. Information on potential risk factors was taken from medical records and interviews with the women. Logistic regression analysis was completed to determine the association between those risk factors and antepartum stillbirth.

Results: During the study period, 4567 women who delivered at the hospital were enrolled as referents, of which 62 had antepartum stillbirths and were re-categorized into the case population. In total, there were 307 antepartum stillbirths. An association was found between the following risk factors and antepartum stillbirth: increasing maternal age (aOR 1.0, 95 % CI 1.0-1.1), less than five years of maternal education (aOR 2.4, 95 % CI 1.7-3.2), increasing parity (aOR 1.2, 95 % CI 1.0-1.3), previous stillbirth (aOR 2.6, 95 % CI 1.6-4.4), no antenatal care attendance (aOR 4.2, 95 % CI 3.2-5.4), belonging to the poorest family (aOR 1.3, 95 % CI 1.0-1.8), antepartum hemorrhage (aOR 3.7, 95 % CI 2.4-5.7), maternal hypertensive disorder during pregnancy (aOR 2.1, 95 % CI 1.5-3.1), and small weight-for-gestational age babies (aOR 1.5, 95 % CI 1.2-2.0).

Conclusion: Lack of antenatal care attendance, which had the strongest association with antepartum stillbirth, is a potentially modifiable risk factor, in that increasing the access to and availability of these services can be targeted. Antenatal care attendance provides an opportunity to screen for other potential risk factors for antepartum stillbirth, as well as to provide counseling to women, and thus, helps to ensure a successful pregnancy outcome.

Clinical Trial Registration: ISRCTN97846009 (url. www.isrctn.com/ISRCTN97846009 ).