Predictive factors for secondary postpartum hemorrhage: a case-control study in Japan

Abstract

Background Secondary postpartum hemorrhage (PPH) is defined as excessive vaginal blood loss occurring between 24 h and 6–12 weeks after birth. The incidence of secondary PPH varies from 0.2% to 3.0%, and the peak incidence ranges from 1 to 2 weeks postpartum. There is no clinical evidence regarding the cause of secondary PPH. Therefore, this study aimed to determine the predictive factors for secondary PPH in an Asian population. Methods A case-control study was performed. The clinical data of 25 secondary PPH patients who had been admitted to our hospital between June 2012 and January 2019 were obtained for this study. Control patients (n = 100) were selected from pregnant women who delivered at the hospital during the same period; they were matched to secondary PPH patients using propensity score matching to adjust for maternal age at delivery, parity, and the use of assisted reproductive technology (ART). A multiple logistic regression analysis was used to determine the predictive factors for secondary PPH. Results The median maternal age was 34 years (range, 24–42 years); 85 (68.0%) women were nulliparous, 31 (24.8%) used ART, and 116 (92.8%) had term deliveries. Immediate PPH (adjusted odds ratio [OR], 2.84; 95% confidence interval [CI], 1.04–7.75) and manual removal of the placenta (adjusted OR, 6.14; 95% CI, 1.21–31.1) were associated with secondary PPH. Conclusion Increasing the awareness of the predictive factors for secondary PPH could play an important role in the recognition and treatment of postpartum morbidity.