Postpartum hemorrhage following vaginal delivery: risk factors and maternal outcomes

OBJECTIVE: Limited understanding of risk factors exists for postpartum hemorrhage (PPH) post-vaginal delivery. The aim of this study was 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 with a second-stage duration <2 h, a second stage >= 3 h was associated with PPH (adjusted odds ratio=2.3; 95% CI = 1.2 to 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 h.