Is opioid use safe in women trying to conceive?

Opioids are commonly prescribed to women of reproductive age, including after delivery and miscarriage. However, to our knowledge, opioid use has not been frequently studied in relation to the common reproductive complications of impaired fecundability and pregnancy. We examined the association of opioid use during the critical window of pregnancy establishment with fecundability and pregnancy loss.

We measured opioid use by urine screening and self-report at multiple time points during preconception and early pregnancy in a prospective cohort of women attempting conception (n=1228). The main outcomes included time to hCG-detected pregnancy and incidence of live birth and pregnancy loss. We estimated fecundability odds ratios (FOR) and risk ratios (RR) with 95% confidence intervals (CI) adjusting for sociodemographic characteristics, reproductive characteristics, and use of antidepressants, tobacco, alcohol, and marijuana.

Prevalence of preconception opioid use was 18% (n=226 of 1228), and in early pregnancy was 5% (n=33 of 685). Opioid use while attempting pregnancy was associated with reduced fecundability (FOR: 0.71; 95% CI: 0.50, 1.0). Risk of pregnancy loss increased as opioid exposure was detected later in gestation, from the beginning of the cycle of conception (RR: 1.5; 95% CI 0.85, 2.6), to week 4 of pregnancy (RR: 2.1; 95% CI: 1.1, 4.1), and to week 4 and 8 of pregnancy (RR: 2.5; 95% CI: 1.3, 5.0).

Our results are consistent with the hypothesis that opioid exposure while trying to conceive may be harmful, even among healthy, non-opioid-dependent women. Possible risks to fecundability and pregnancy viability are relevant to patients and providers when evaluating pain management approaches.ClinicalTrials.gov registration number: #NCT00467363.