Postpartum Depression Following a Substance-Exposed Pregnancy: The Roles of Age, Race/Ethnicity, and Mental Health History

Purpose: To explore the impact of age, race/ethnicity, and mental health history on the prevalence of postpartum depression (PPD) among individuals who are pregnant and using substances. Background: Associations exist between substance use during pregnancy and PPD, however it remains unclear how this varies among different age groups, racial/ethnic groups, or how mental health history influences these outcomes. PPD is one of the most prevalent morbidities related to pregnancy, affecting 13% to 19% of women who give birth. There is significant research highlighting the risks associated with PPD emphasizing the prevalence and negative outcomes for both the mother and child Methods: This study involved a retrospective review of electronic medical charts from two academic pediatric practices in the Midwestern U.S. The study included a racially, culturally, and geographically diverse sample of patients, designed to oversample those who used tobacco, marijuana, and/or opioids during pregnancy. Participants were limited to maternal-child dyads involving children born since July 2016 with pediatric medical records available through age 3, and with linked maternal prenatal and delivery records also available. All data collection for this study was performed via manual review of medical records for an extensive set of study variables for the parent study including maternal medical and background factors, and child outcomes. Patient dyads were included in the parent study if prenatal records were available for the mother, delivery records were available for both the mother and the child, and fewer than three well check appointments were missing up to one year of life for the child. For the current study, only women who used substances during pregnancy were included. The primary outcome was the development of postpartum depression in the mother. Postpartum depression was determined by maternal responses on the Edinburgh Postpartum Depression Scale (EPDS), which was administered to mothers at all pediatric well child checks up to 12 months of age at our participating practices, as well as maternal report of an outside diagnosis or treatment for PPD. A mother was considered positive for PPD if at least one EPDS score was 10 or greater, or if she reported she had been diagnosed or treated for PPD elsewhere. Primary predictors were maternal race/ethnicity, age, and mental health history, all of which were extracted from the medical records. Additional demographic and medical information were extracted for the purposes of describing the study sample and exploring additional predictors of PPD. Descriptive analyses were utilized to describe the sample, and chi-square and t-test analysis was used to examine bivariate relationships between PPD and the other study variables. To determine which variables were most predictive of PPD, logistic regression analyses was used with dichotomous PPD as the outcome, and simultaneous entry of potential predictors including maternal age, race/ethnicity, marital status, medical insurance status (income dependent vs private, a marker of SES), adequacy of prenatal care utilization, self-report and biochemically confirmed pregnancy substance use (tobacco, marijuana, and opioids), and having been diagnosed with a mental health condition prior to pregnancy. Results: The study sample contained all cases that were part of the larger Maternal-Child EMR project that involved substance use during pregnancy. Of those 185 cases, 173 had complete data on the primary predictor and outcome variables and were retained for the current report. One quarter of this sample (25.2%) was positive for PPD. In bivariate analyses, compared to those who did not experience PPD, those who did were significantly more likely to have private insurance. Overall, logistic regression analysis showed the predictors explained nearly a third of the variance in the experience of PPD (R2 = .30, p= .036). Two factors specifically were significant independent predictors of PPD, with those who had private medical insurance more than four times more likely than those with income dependent insurance to develop PPD, and those who used marijuana in pregnancy nearly three times more likely to develop PPD than those who did. After accounting for marijuana use and type of insurance and the other factors in the model, while having a prior mental health issue more than doubled the likelihood of developing PPD, this relationship was not statistically significant. Conclusions: This study underscores the multifaceted nature of postpartum depression (PPD) among pregnant individuals who use substances, revealing that marijuana use and private insurance status are significant independent predictors of PPD risk. In contrast, while age, race/ethnicity, and preexisting mental health conditions were associated with higher PPD rates, these factors did not reach statistical significance in the final model, reflecting complex interrelationships among income, mental health history, and substance use. The unexpectedly higher PPD incidence among women with private insurance may highlight potential barriers to diagnosis or treatment for low-income women in underserved areas, warranting further investigation.