Prescription opioid use after vaginal delivery and subsequent persistent opioid use and misuse.

Background: Vaginal delivery is the most common reason for hospitalization in the United States, and approximately 30% of women fill an opioid prescription after vaginal delivery, making this a common source of opioid exposure in women of reproductive age.

Objective: This study aimed to evaluate the effect of receiving an opioid prescription after vaginal delivery on the risk of subsequent persistent opioid use, opioid use disorders, and overdose.

Study Design: We assembled a nationwide cohort of Medicaid beneficiaries in the United States using the Medicaid Analytic eXtract 2009-2014. The study population included pregnant women who delivered vaginally between 2009 and 2013 and were continuously enrolled in Medicaid from 90 days before to 365 days after delivery. We identified patients with prescription opioids dispensed within 7 days of the date of vaginal delivery. Persistent opioid use was defined as ≥10 opioid fills or >120 days' supply dispensed from 30 to 365 days after delivery. Incident diagnoses of opioid use disorder and overdose were ascertained during the same interval. Propensity score matching was used to control for potential confounding factors.

Results: Among 459,829 pregnancies ending in vaginal deliveries, 140,807 (30.62%) had an opioid dispensed within 7 days of delivery. Overall, 5770 of 140,807 (4.10%) women who filled an opioid prescription vs 2668 of 319,022 (0.84%) unexposed women had subsequent persistent opioid use, with an unadjusted relative risk of 4.90 (95% confidence interval, 4.68-5.13) and a risk difference of 3.26% (95% confidence interval, 3.15-3.37). After propensity score matching, the risk remained higher among pregnancies with an opioid prescription dispensed, with a relative risk of 2.57 (95% confidence interval, 2.43-2.72) and a risk difference of 2.21% (95% confidence interval, 2.08-2.33), which was confirmed by the instrumental variable analysis with a risk difference of 1.31% (95% confidence interval, 1.06-1.56) by using the rate of opioid prescribing at the delivery facility in a given geographic region as the instrument. The adjusted relative risk of newly diagnosed opioid use disorder and overdose was 1.48 (95% confidence interval, 1.40-1.57) and 1.92 (95% confidence interval, 1.20-3.09), respectively.

Conclusion: Opioid dispensing following vaginal delivery is associated with future persistent opioid use and misuse, independent of confounding factors. Opioid prescriptions to women after vaginal delivery should be avoided, except in rare circumstances.