Risk factors for severe postpartum hemorrhage requiring blood transfusion after cesarean delivery for twin pregnancy: a nationwide cohort study

Background: Postpartum hemorrhage (PPH) is a leading cause of maternal morbidity and mortality. Twin pregnancy and cesarean delivery are well-known risk factors for PPH. However, few studies have investigated PPH risk factors in mothers who have undergone cesarean delivery for twin pregnancies. Therefore, this study investigated the risk factors associated with severe PPH after cesarean delivery for twin pregnancies. Methods: We searched and reviewed the Korean Health Insurance Review and Assessment Service's claims data from July 2008 to June 2021 using the code corresponding to cesarean delivery for twin pregnancy. Severe PPH was defined as hemorrhage requiring red blood cell (RBC) transfusion during the peripartum period. The risk factors associated with severe PPH were identified among the procedure and diagnosis code variables and analyzed using univariate and multivariate logistic regressions. Results: We analyzed 31,074 cesarean deliveries for twin pregnancies, and 4,892 patients who underwent cesarean deliveries for twin pregnancies and received RBC transfusions for severe PPH were included. According to the multivariate analysis, placental disorders (odds ratio, 4.50; 95% confidence interval, 4.09- 4.95; P < 0.001), general anesthesia (2.33, 2.18-2.49; P < 0.001), preeclampsia (2.20, 1.99-2.43; P < 0.001), hemolysis, elevated liv-er enzymes, low platelets (HELLP) syndrome (2.12, 1.22-3.68; P = 0.008), induction failure (1.37, 1.07-1.76; P = 0.014), and hypertension (1.31, 1.18-1.44; P < 0.001) predicted severe PPH. Conclusions: Placental disorders, hypertensive disorders such as preeclampsia and HELLP syndrome, and induction failure increased the risk of severe PPH after cesarean delivery for twin pregnancy.