Estimating the incidence and risk factors of postpartum hemorrhage from the national ENACT network.

Aggregated counts from electronic health records (EHRs) provide a rich source of real-world data that can be leveraged to investigate critical medical conditions such as postpartum hemorrhage (PPH). We used the Evolve to Next-Gen Accrual to Clinical Trials (ENACT) network, a large, federated network of EHRs, and conducted repeated annual cross-sectional analyses on PPH incidence, risk factors, and maternal comorbidities in a large cohort of 591,375 delivery hospitalizations during the period 2005 to 2022. During this time, there was a statistically significant increasing trend in the incidence of PPH, which is consistent with previous studies. Native Hawaiian or Other Pacific Islander women had the highest incidence of PPH (12.14%), followed by Asian (11.04%) and Black or African American (9.36%) women. In PPH deliveries, the top-ranked risk factor was placenta previa or accreta (19.58%), the top-ranked comorbidity was primary cesarean delivery (41.08%), and the commonest cause was uterine atony (76.5%).