BackgroundPerinatal mood and anxiety disorders are common, serious complications of pregnancy. Disparities exist by race and income in the prevalence and treatment of these conditions, and overall treatment rates remain low. Outside of pregnancy, a small body of literature suggests that rural residency may contribute to higher rates of depression for those who identify as women. Among more diverse populations, however, evidence suggests urban residency may be associated with higher rates of depression among women of color. It is not known whether these trends hold true for mood and anxiety disorders during pregnancy and postpartum. ObjectivesWe examined differences in the detection and treatment of perinatal mood and anxiety disorders by rural and urban residence and assessed if the observed differences varied by maternal race/ethnicity. Study DesignWe conducted a cross sectional study using linked Medicaid claims and birth certificate records from Oregon and South Carolina from 2016 to 2020. We identified perinatal mood and anxiety disorder diagnoses during the perinatal period (pregnancy and within 60 days postpartum) using International Classification of Disease 9/10 codes and enumerated receipt of pharmaco- and psychotherapy treatment using Medicaid claims. We used logistic regression models controlling for relevant clinical and sociodemographic characteristics to estimate associations between rural residence and mood disorder detection and treatment. ResultsAmong the 185,809 births in our sample, 27% of births (n=50,820) were to people who lived in rural areas and 73% (n=134,989) to those in urban areas. Prevalence of any perinatal mood and anxiety disorders diagnosis was higher for urban residents (19.5%) than for rural residents (18.0%, p<0.001). Overall treatment rates were low among people with a perinatal mood and anxiety disorder (42% (n=14,789)). In our adjusted models, those living in urban areas had higher odds of a perinatal mood and anxiety disorder diagnosis (aOR=1.059, 95% CI 1.059-1.059, p<0.001). We found a significant interaction between maternal race and rurality (p<0.001). When we stratified by race, we found that among those who identified as Black, the odds of a perinatal mood and anxiety disorder diagnosis were increased for urban residents (OR=1.188, 95% CI 1.188-1.188), whereas among those who identified as white there was no such increased odds (OR=1.027, 95% CI 0.843-1.252). ConclusionsWe saw small but meaningful differences between rural and urban residence in perinatal mood and anxiety disorder diagnosis rates. We detected an interaction between race and rural versus urban maternal residence that impacted the observed differences. By elucidating the intersection between race and other sociodemographic factors, we hope more targeted and meaningful investments can be made in the communities most at need.