A comparative analysis of Postpartum Hemorrhage incidence and influencing factors between nulliparous and multiparous women in Hunan Province, China: A multicenter retrospective cohort study

Objectives: Postpartum hemorrhage (PPH) is a common cause of maternal death worldwide, but data on PPH incidence and influencing factors for nulliparous and multiparous women is scarce. So, the study aimed to assess the differences in PPH incidence and influencing factors between nulliparous and multiparous women. Methods: A multicenter retrospective cohort study was conducted among women who gave birth at >= 28 weeks of gestation in Hunan Province, China, from January 2017 to December 2018. Logistic regression assessed PPHinfluencing factors, and the receiver operating characteristic curve (ROC curve) assessed the predictive performance of identified factors. Results: A total of 144,845 postpartum women were included in the study. The incidence of PPH (blood loss >= 500 ml) was 2.1 % and 1.7 % for nulliparous and multiparous women, respectively. Among the nulliparous and multiparous women, similar influencing factors of PPH included erythrocyte suspension transfusion before childbirth, anemia, soft -birth canal avulsion, Cesarean -section, placenta abruption, and general anesthesia administration before birth. Thrombophlebitis was associated [aOR 18.46(1.67-20.31)] with PPH among only the nulliparous women, while instrument -assisted birth [aOR 1.95(1.16-3.28)] and gestational hypertension [aOR 1.57(1.13-2.19)] were associated with PPH among only the multiparous women. The areas under the ROCcurve for the overall -cohort, nulliparous, and multiparous groups were [0.829(0.821-0.838)], [0.828 (0.815-0.840)] and [0.833(0.822-0.844)], respectively. Conclusion: PPH incidence is higher among nulliparous women than among multiparous women, but influencing factors vary relatively by parity. The study findings provide new insights into the use of different approaches to PPH prevention for nulliparous and multiparous women in clinical practice.