Postpartum Hemorrhage Morbidity in Deliveries Complicated by Elevated Body Mass Index

The relationship between body mass index (BMI) ≥ 30 in pregnancy and postpartum hemorrhage (PPH) has been unclear. While some risk stratification protocols classify elevated BMI as a moderate risk factor others do not. This study aimed to examine the effect of elevated BMI on PPH in a contemporary population.This retrospective cohort study included all singletons ≥14 weeks with recorded BMI who delivered at a Level IV center for two consecutive years. The exposure group was sub-categorized into BMI of 30 to 39.9 and BMI ≥ 40 kg/m², with a planned subgroup by mode of delivery. Data was collected by clinicians, and the composite maternal hemorrhagic outcome (CMHO) was defined as: blood loss ≥ 1,000 mL, interventions for atony including use of uterotonics (excluding prophylactic oxytocin), mechanical tamponade, surgical intervention, venous thromboembolism, admission to the intensive care unit, hysterectomy, or maternal death. Adjusted relative risks (aRR) with 95% confidence intervals (CI) were calculated using multivariate Poisson regression with robust error variance.Of 8,623 deliveries in the study period, 8,340 (96.7%) met inclusion criteria, with 2,943 (35%) with BMI < 30.0, 3,900 (46%) with BMI of 30 to 39.9 kg/m², and 1,497 (17%) with BMI of ≥40 kg/m². CHMO was increased for BMI of 30 to 39.9 (aRR: 1.16; 95% CI: 1.04-1.29) and ≥40.0 (aRR: 1.19; 95% CI: 1.04-1.36), largely due to increased risk of blood loss ≥ 1,000 and uterotonic use. A subgroup analysis by mode of delivery noted that increased risk for CHMO was only present in BMI ≥ 40 for vaginal deliveries (aRR: 1.35; 95% CI: 1.10-1.65) and only for BMI of 30 to 39.9 in cesarean delivery (aRR: 1.28; 95% CI: 1.10-1.50).Parturients with BMI ≥ 30 had a higher risk of hemorrhage-related morbidity compared with patients with BMI < 30, however, clinical management and impact need further investigation. · Patients with an elevated BMI had a higher risk of hemorrhage-related morbidity.. · Individuals with BMI ≥ 40 kg/m2 are at increased risk of hemorrhage with vaginal deliveries.. · With rising BMI rates, research on perinatal risks and targeted interventions is crucial for better..