Objective: To investigate risk factors for postpartum hemorrhage (PPH) in vaginal deliveries and the influence of previous PPH on the subsequent pregnancy.
Study design: A retrospective cohort study including first singleton deliveries between the years 1988 and 2012 was performed comparing deliveries with and without PPH. In addition, perinatal outcomes of the subsequent pregnancy were evaluated. Multivariable analysis was performed to control for confounders.
Results: PPH complicated 0.8% of all first vaginal deliveries. Significant risk factors for PPH in vaginal delivery, using a multiple logistic regression model, were: post-term pregnancy, fertility treatments, hypertensive disorders, labor dystocia during the 2nd, and perineal tears grade 2 and 3, respectively. Previous PPH was found to be an independent risk factor for PPH in the subsequent pregnancy. Moreover, previous PPH was found to be a significant risk factor for cesarean section (CS) deliver, to complicate delivery with revision of uterus cavity, anemia, and to require blood transfusion.
Conclusion: Previous PPH poses a risk for recurrent PPH in subsequent delivery and an increased risk for CS. As PPH remains one of the major causes of maternal morbidity, this study strengthens the need for a comprehensive evaluation of prior PPH as a major risk factor for PPH recurrence.
Keywords: Post-partum hemorrhage; post-term pregnancy; previous PPH; risk factors.