RESUMEN
Objective: To analyze associated factors and adverse pregnancy outcomes of postpartum hemorrhage in the caesarean section of puerperae with different types of placenta previa. Methods: This retrospective research was a case-control study. Puerperae with cesarean section of placenta previa from January 2019 to December 2020 in Women's Hospital, School of Medicine, Zhejiang University were collected and divided into the<1 000 ml control group or ≥1 000 ml postpartum hemorrhage group according to the amount of blood loss during cesarean section. Differences in continuous variables were analyzed by t-test and categorical variables were analyzed by χ2 test. The risk factors of postpartum hemorrhage were analyzed by logistic multivariate regression. Results: A total of 962 puerperae were enrolled with 773 cases in the control group and 189 cases in the postpartum hemorrhage group. The incidence of gestational weeks, gravidity, parity, induced abortion, placental accreta and preoperative hemoglobin<110 g/L was significantly different between two groups in different types of placenta previa (P<0.001). Logistic multivariate regression model analysis showed that the independent risk factors of postpartum hemorrhage in the caesarean section of low-lying placenta included placental accreta (OR=12.713, 95%CI: 4.296-37.625), preoperative hemoglobin<110 g/L (OR=2.377, 95%CI: 1.062-5.321), and prenatal vaginal bleeding (OR=4.244, 95%CI: 1.865-9.656). The independent risk factors of postpartum hemorrhage in the caesarean section of placenta previa included once induced abortion (OR=2.789, 95%CI:1.189-6.544), induced abortion≥2 (OR=2.843, 95%CI:1.101-7.339), placental accreta (OR=6.079, 95%CI:3.697-9.996), HBsAg positive (OR=3.891, 95%CI:1.385-10.929), and placental attachment to the anterior uterine wall (OR=2.307, 95%CI:1.285-4.142). The rate of postpartum hemorrhage and premature delivery in puerperae with placenta previa was higher than that in puerperae with low-lying placenta (P<0.001). Conclusions: The associated factors of postpartum hemorrhage in puerperae with different types of placenta previa are different. Placenta accreta is the common risk factor of postpartum hemorrhage in puerperae with low-lying placenta and placenta previa.