Preeclampsia as a Risk Factor for Postpartum Hemorrhage: A Systematic Review and Meta-Analysis

Postpartum hemorrhage (PPH) remains a leading cause of maternal mortality globally. Although endothelial dysfunction and vascular alterations in preeclampsia may increase PPH risk, this association lacks robust synthesis. We conducted a systematic review and meta-analysis to quantify the impact of preeclampsia on PPH.

Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we analyzed observational studies (case-control/cohort) assessing PPH as the primary outcome. Subgroup analyses examined delivery mode and geographic region. Risk of bias was evaluated using the Newcastle-Ottawa Scale (International Prospective Register of Systematic Reviews - PROSPERO: CRD42023441579).

Twelve studies (7 case-control, 5 retrospective cohorts) comprising 2 102 987 pregnancies (61 139 preeclampsia cases) were included. Preeclampsia significantly increased PPH risk (OR 1.95; 95% CI 1.70-2.23). Geographic subgroup analyses revealed highest risk in Europe (OR 2.18; 95% CI 1.67-2.14), followed by America (OR 1.95; 95% CI 1.50-2.55) and Asia (OR 1.67; 95% CI 1.28-2.18). High heterogeneity (I² = 67.5%) reflected methodologic variations. Evidence certainty was moderate (Grading of Recommendations Assessment, Development, and Evaluation); some studies indicated bias from unadjusted confounders.

Preeclampsia is associated with a near-doubling of PPH risk (moderate-certainty evidence). Clinical protocols should consider preeclampsia as a significant risk factor for PPH, warranting increased vigilance during delivery and the postpartum period.