Investigating and modelling risk factors for primary postpartum haemorrhage among childbearing Women in the Northern Province of Rwanda: A Case Control Study

Abstract Background: The vast majority of maternal deaths occur in Low- and Middle-Income Countries. Postpartum haemorrhage (PPH) remains a major global burden contributing to high maternal mortality and morbidity rates. Assessment of PPH risk factors should be undertaken during antenatal, intrapartum and postpartum periods for timely prevention of maternal morbidity and mortality associated with PPH. The aim of this study is to investigate and model risk factors for primary PPH in Rwanda. Methods: We conducted an observational case-control study of 430 (108 cases: 322 controls) pregnant women with gestational age of 32 weeks and above who gave birth in five selected health facilities of Rwanda between January and June 2020. Poisson regression, a generalized linear model with a log link and a Poisson distribution was used to estimate the risk ratio of factors associated with PPH. The research protocol was approved by the University of Rwanda, College of Medicine and Health Sciences Institutional Ethics Review Board. Results: The overall prevalence of primary PPH was 25.2%. The following risk factors were identified: antepartum haemorrhage (RR=3.36; 95% CI 1.80- 6.26, P<0.001); intrauterine fetal death (RR=1.93; 95% CI 0.93- 4.03, P<0.077); multiple pregnancy (RR=1.83; 95% CI 1.11- 3.01, P=0.016); haemoglobin level <11 gr/dL (RR=1.51; 95% CI 1.00- 2.30, P=0.050), and premature rupture of membranes (RR=0.58; 95% CI 0.32- 1.05, P<0.077). During the intrapartum and immediate postpartum period, the main causes of primary PPH were: uterine atony (RR=6.70; 95% CI 4.78- 9.38, P<0.001), retained tissues (RR= 4.32; 95% CI 2.87- 6.51, P<0.001); and lacerations of genital organs after birth (RR= 2.14; 95% CI 1.49- 3.09, P<0.001). Coagulopathy was not prevalent in primary PPH. Conclusion: Based on our findings, uterine atony remain the foremost cause of primary PPH. As well as other established risk factors for PPH, antepartum haemorrhage and intra uterine fetal death should be included as risk factors in the development and validation of prediction models for PPH. Large scale studies are needed to investigate further potential PPH risk factors.