Prescription Opioid Dose After Vaginal Delivery and the Risk of Serious Opioid-Related Events: A Retrospective Cohort Study.

Abstract

Postpartum opioid use remains common among women with uncomplicated vaginal delivery and may increase the risk of serious opioid-related events. Therefore, we examined the association between the dose of the first filled opioid prescription after vaginal delivery and the subsequent risk of serious opioid-related events. We conducted a retrospective cohort study among women enrolled in Tennessee Medicaid with a vaginal delivery (2007-2015). We used Cox proportional hazards regression to model adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) for serious opioid-related events after delivery according to the dose (morphine milligram equivalents [MME]) of the first postpartum opioid prescription, accounting for comorbidities, medication use, parity, and delivery complications. Serious opioid-related events were defined as the occurrence of persistent opioid use, a methadone or buprenorphine fill, opioid use disorder diagnosis, opioid overdose, or opioid-related death. We used filled pharmacy data to characterize the dose of the first postpartum opioid prescription filled within 4days after delivery. More than one-half of women (53.2%; n=147,598) filled an opioid prescription within 4days of a vaginal delivery. After accounting for baseline risk factors, filling a postpartum opioid prescription was associated with an increased risk of serious opioid-related events across all dose categories, compared with women filling none (aHR 1-99 MME, 1.52; 95% CI, 1.33-1.74; aHR 100-149 MME, 1.41; 95% CI, 1.26-1.58; aHR 150-199 MME, 1.40; 95% CI, 1.26-1.57: and aHR ≥200 MME, 1.60; 95% CI, 1.43-1.78). Filling a postpartum opioid prescription after a vaginal delivery was associated with an increased risk of serious opioid-related events, regardless of dose. Prescribing guidelines should discourage the routine prescribing of opioids after vaginal delivery.