Trends and Racial and Ethnic Disparities in Hospital‐Reported Perinatal Mental Disorders in California

BACKGROUND: Perinatal mental disorders (PMD), including perinatal mood and anxiety disorders (PMAD) and serious mental illness (SMI), pose a critical public health concern with consequences for birthing persons and their children. Evidence on racial and ethnic disparities is mixed, and little is known about how these disparities have changed over time. OBJECTIVE: To evaluate long-term trends and racial and ethnic disparities in the prevalence of hospital-reported PMD. METHODS: We analysed all live hospital births in California from 1997 to 2019 (N = 10,703,966). PMAD and SMI were identified using ICD-9-CM and ICD-10-CM codes from hospital discharge records. We estimated age-standardised prevalence and average annual percentage change (AAPC) by race/ethnicity and used modified Poisson regression to estimate unadjusted and adjusted risk ratios (RRs). Temporal changes in disparities were examined using smoothed multi-year periods. RESULTS: Overall, PMD prevalence was 2.0% (PMAD: 1.6%; SMI: 0.6%) and increased across all racial and ethnic groups, with Hispanic and Asian or Pacific Islander birthing persons experiencing the largest AAPC. Compared to their non-Hispanic white peers, American Indian or Alaska Native birthing people had a higher risk of any PMD (RR 1.16, 95% confidence interval [CI] 1.11, 1.21), and Black birthing people had a higher unadjusted SMI risk (RR 1.10, 95% CI 1.07, 1.13). Over time, disparities showed persistently lower risk among Asian or Pacific Islander and Hispanic individuals, and comparable or higher risk among American Indian or Alaska Native individuals; SMI risk among Black birthing people approached parity with White birthing people in several periods. CONCLUSIONS: Hospital-reported PMD increased substantially over two decades, with racial and ethnic differences likely shaped by structural barriers to care, stigma, and diagnostic bias that contribute to underdiagnosis among minoritised populations. Future research should examine social and structural drivers to inform equity-focused interventions.