Maternal and infant characteristics associated with maternal opioid overdose in the year following delivery

Background and aims: Opioid-related overdose is increasingly linked to pregnancy-associated deaths, but factors associated with postpartum overdose are unknown. We aimed to estimate the strength of the association between maternal and infant characteristics and postpartum opioid-related overdose.

Design: Retrospective cohort study using a linked, population-level data set.

Setting: Massachusetts, United States.

Conclusion: Among women who delivered live infants in Massachusetts, USA between 2012 and 2014, maternal diagnosis of OUD, prior non-fatal overdose, infant diagnosis of NAS and high unscheduled health-care utilization appeared to be positively associated with postpartum opioid overdose. However, more than half of postpartum overdoses in that period were to women without a diagnosis of OUD. Engagement in methadone or buprenorphine treatment in the month prior to delivery was not sufficient to reduce the odds of postpartum overdose.

Participants: Women who delivered one or more live births from 2012 to 2014 (n = 174 517).

Measurements: The primary outcome was opioid-related overdose in the postpartum year. We used multivariable logistic regression to explore the independent associations of maternal (demographics, substance use, pregnancy) and infant [gestational age, birthweight, neonatal abstinence syndrome (NAS)] characteristics with postpartum opioid overdose. Findings were stratified by maternal opioid use disorder (OUD) diagnosis.

Findings: There were 189 deliveries to women who experienced ≥ 1 opioid overdose in the first year postpartum (11 of 10 000 deliveries). Among women with postpartum opioid overdose, 46.6% had an OUD diagnosis within 12 months before delivery. In our adjusted model, maternal diagnosis of OUD [adjusted odds ratio (aOR) = 3.61, 95% confidence interval (CI) = 1.73-7.51] and prior non-fatal overdose (aOR = 2.40, 95% CI = 1.11-5.17) were most strongly associated with postpartum overdose. After stratifying by OUD status, infant diagnosis of NAS (OUD⁺ aOR = 2.03, 95% CI = 1.26-3.27; OUD^- aOR = 2.79, 95% CI = 1.12-6.93) and high unscheduled health-care utilization (OUD⁺ aOR = 2.27, 95% CI = 1.38-3.73; OUD^- aOR = 2.11, 95% CI = 1.24-3.58) were positively associated with postpartum overdose in both groups.