Postpartum Hemorrhage Following Vaginal Delivery: Risk Factors and Maternal Outcomes

BACKGROUND: Limited understanding exists of risk factors for PPH post-vaginal delivery. OBJECTIVE: To identify risk factors for PPH post-vaginal delivery within a contemporary obstetric cohort. STUDY DESIGN: Retrospective case-control study. PPH was classified by an estimated blood loss ≥ 500 mL. Risk factors for PPH were identified using univariable and multivariable logistic regression. We secondarily investigated maternal outcomes and medical and surgical interventions for PPH management. RESULTS: The study cohort comprised 159 cases and 318 controls. Compared to a second stage duration <2 hours, a second stage ≥ 3 hours was associated with PPH (Adjusted Odds Ratio=2.3; 95% CI=1.2 – 4.6). No other clinical or obstetric variables were identified as independent risk factors for PPH. Among cases, 4% received red blood cells and 1% required intensive care admission. CONCLUSION: Although PPH-related morbidity may be uncommon after vaginal delivery, PPH should be anticipated for women after a second stage ≥3 hours.