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 for investigating 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, to characterize national trends, risk factors, and comorbidities associated with PPH in a cohort of 705,120 women hospitalized for delivery from 2005 to 2022. During this period, there was a statistically significant increase in the incidence of PPH, consistent with previous studies. Asian women had the highest incidence of PPH (10.33%), followed by Black or African American (8.33%) and American Indian or Alaska Native (8.05%) women. In PPH deliveries, the top-ranked risk factor was severe eclampsia (18.51%), the top-ranked comorbidity was operative vaginal delivery (16.98%), and the commonest cause was uterine atony (83.06%). We demonstrated that a large federated EHR network such as ENACT can be used to generate population-level epidemiological findings, albeit with some limitations.