Postpartum emergency department visits and readmissions in the 90 days after a singleton delivery.

Introduction: Maternal morbidity and mortality are often concentrated in the first 90 days postpartum. Postpartum emergency department (ED) and hospital use provide valuable insight into peripartum health outcomes. We performed a health system-wide analysis of sociodemographic, clinical, and hospital-level factors associated with 90-day postpartum ED visits and inpatient hospital admissions. Methods: This retrospective cohort study of all 90-day postdelivery ED visits or inpatient admissions, referred to as "90-day postpartum hospital use," in a nine-hospital Midwest health system included all births from January 2018 to June 2023. We applied a multilevel eco-social framework to examine associations between factors within three domains and 90-day postpartum hospital use. Exposure variables included sociodemographic factors (age, race/ethnicity, insurance, language, census zip code percent poor households), clinical factors (parity, clinical risk factors, body mass index [BMI], severe maternal morbidity during delivery admission [SMM], and other birth outcomes), and hospital type. We applied univariable and multivariable Poisson regression analyses. Results: Of 104,076 deliveries, 6879 (6.6%) were followed by 90-day postpartum hospital use (ED visit Conclusion: In this health system-wide analysis, 90-day postpartum hospital use is associated with a combination of sociodemographic, clinical, and hospital factors, underscoring the need for a comprehensive mitigation strategy.