Objective: To estimate fatal and nonfatal opioid overdose events in pregnant and postpartum women in Massachusetts, comparing rates in individuals receiving and not receiving pharmacotherapy for opioid use disorder (OUD).
Methods: We conducted a population-based retrospective cohort study using linked administrative and vital statistics databases in Massachusetts to identify women with evidence of OUD who delivered a liveborn neonate in 2012-2014. We described maternal sociodemographic, medical, and substance use characteristics, computed rates of opioid overdose events in the year before and after delivery, and compared overdose rates by receipt of pharmacotherapy with methadone or buprenorphine in the prenatal and postpartum periods.
Results: Among 177,876 unique deliveries, 4,154 (2.3%) were to women with evidence of OUD in the year before delivery, who experienced 242 total opioid-related overdose events (231 nonfatal, 11 fatal) in the year before or after delivery. The overall overdose rate was 8.0 per 100,000 person-days. Overdoses were lowest in the third trimester (3.3/100,000 person-days in the third trimester) and then increased in the postpartum period with the highest overdose rate 7-12 months after delivery (12.3/100,000 person-days). Overall, 64.3% of women with evidence of OUD in the year before delivery received any pharmacotherapy in the year before delivery. Women receiving pharmacotherapy had reduced overdose rates in the early postpartum period.
Conclusion: Pregnant women in Massachusetts have high rates of OUD. The year after delivery is a vulnerable period for women with OUD. Additional longitudinal supports and interventions tailored to women in the first year postpartum are needed to prevent and reduce overdose events.