Trends in Postpartum Depression by Race, Ethnicity, and Prepregnancy Body Mass Index.

Importance: Postpartum depression (PPD) poses significant risks to maternal and child health. Understanding temporal trends is crucial for evaluating prevalence and identifying populations at risk.

Objective: To evaluate recent trends in PPD and assess how these trends are associated with race, ethnicity, and prepregnancy body mass index (BMI).

Design, setting, and participants: A serial, cross-sectional analysis using data from the Kaiser Permanente Southern California (KPSC) electronic health records (EHRs), with live and stillbirths at 20 or more weeks of gestation who were KPSC members at the time of delivery between 2010 and 2021. Data were analyzed from July 2022 to August 2023.

Exposures: Self-reported race, ethnicity, and recorded prepregnancy BMI.

Main outcome measures: PPD cases were identified using validated diagnostic codes and prescription records within 12 months postpartum in the KPSC EHRs. Patients with an Edinburgh Postnatal Depression Scale score of 10 or more within 6 months postpartum were further evaluated by a mental health specialist for formal PPD diagnosis.

Results: In this study of 442 308 pregnancies, the median (IQR) maternal age at delivery was 31 (27-34) years. The cohort was racially and ethnically diverse, with 62 860 individuals (14.2%) identifying as Asian/Pacific Islander, 231 837 (52.4%) as Hispanic, 33 207 (7.5%) as non-Hispanic Black, 108 201 (24.5%) as non-Hispanic White, 5903 (1.3%) as multiple or other, and 300 (0.1%) unknown. PPD prevalence doubled over the study period, increasing from 9.4% in 2010 to 19.0% in 2021. The largest increases were observed among Asian and Pacific Islander participants (280% increase) and non-Hispanic Black participants (140% increase). PPD rates increased across all BMI categories, particularly among individuals with obesity (class I) and morbid obesity (class II/III).

Conclusions and relevance: In this cross-sectional study, PPD diagnosis increased significantly across all racial and ethnic groups and BMI categories over the past decade. While rising PPD may reflect improved screening and diagnosis practices, the persistently high rates highlight the need to develop and implement interventions to prevent the condition while expanding efforts to mitigate the impact of PPD on maternal and child health.