Preterm Delivery and Postpartum Substance Use: Implications for Maternal Mental Health in Obstetric Care

Introduction Preterm delivery is an obstetric complication linked to an increased risk of postpartum depression (PPD), which often goes undiagnosed. Individuals with PPD may self-medicate to manage depressive symptoms. While postpartum substance use is well-documented, few studies have assessed whether preterm delivery is associated with new-onset substance use. A greater understanding of birth trauma as a factor for new-onset substance use in postpartum women can broaden our understanding of postpartum mood disorders and propel greater inquiry into mental health care in peri- and postpartum women. Methods A retrospective cohort study was conducted using TriNetX to assess whether preterm delivery increases the risk of new-onset postpartum substance use. Propensity score matching was performed based on age, age at delivery, and race. Patients with a history of substance use disorder were excluded. Two postpartum periods (1-180 and 181-365 days) were analyzed using risk and hazard ratios (HRs), Kaplan-Meier analysis, and log-rank tests. The proportional hazards assumption was tested using Schoenfeld's residuals. Results After propensity score matching, 104,187 participants were included per cohort. Preterm delivery was associated with an increased risk of new-onset substance use across all four substances. In the early postpartum period, HRs for preterm vs. full-term delivery were: nicotine 2.193 (95% CI: 1.888, 2.547), cannabis 2.486 (95% CI: 1.773, 3.484), opioids 4.040 (95% CI: 2.245, 7.273), and alcohol 2.451 (95% CI: 1.547, 3.883). These associations persisted, though slightly attenuated, in the late postpartum period. Discussion Preterm delivery was linked to increased new-onset postpartum substance use across substances and time periods, with the strength of association varying by substance and timing. These identified associations between preterm labor and postpartum substance use may suggest a link between preterm birth and coping behaviors such as self-medication. Proactive postpartum screening and trauma-informed care are crucial for improving outcomes in patients with preterm delivery. Maternal care must integrate trauma-informed care and behavioral health services.