Opioid exposure during pregnancy may raise risk of preterm delivery

Pregnant women who receive higher doses of prescription opioids are at increased the risk of delivering prematurely, according to a study.

Researchers looked at a retrospective cohort of pregnant patients enrolled in Tennessee Medicaid. They identified pregnant people between 15 and 44 years of age without opioid use disorder who experienced birth of a single foetus at 24 weeks of gestation or greater with linked birth certificate data.

The analysis included 25,391 people who had spontaneous preterm birth (case group: median age 23 years, 58.1 percent non-Hispanic White) and 225,696 people who delivered at term (control group). The case and control groups were matched according to pregnancy start date, race, ethnicity, age at delivery within 2 years, and history of prior preterm birth.

Conditional logistic regression was applied to assess the incidence of spontaneous preterm birth in relation to the total opioid morphine milligram equivalents (MME) dispensed, with adjustments for parity, prepregnancy body mass index, education level, tobacco use, hepatitis infections, and pain indications.

A total of 18,702 participants (7.4 percent) filled an opioid prescription in the 60 days prior to the index date. A 4-percent increase in the odds of spontaneous preterm birth was seen for every doubling of nonzero opioid MME exposure during pregnancy (adjusted odds ratio, 1.04, 95 percent confidence interval, 1.01–1.08).

The findings support the use of the lowest effective opioid dose for pain management, according to the researchers.