BACKGROUND: Reproductive-aged women in the United States commonly use pain relieving medications. However, the effects of these medications on fecundability are unknown.
OBJECTIVES: To evaluate the association between fecundability and preconception use of pain medications.
METHODS: Data were analyzed from Pregnancy Study Online (PRESTO), a North American preconception cohort study. A total of 1763 female pregnancy planners were followed prospectively until self-reported pregnancy, initiation of fertility treatment, loss-to-follow-up, or 12 months, whichever occurred first. Past-month use of acetaminophen, aspirin, ibuprofen, naproxen, and opioids was reported at baseline and at each bimonthly follow-up. Multivariable-adjusted fecundability ratios (aFR) and 95% confidence intervals (CI) were calculated using proportional probabilities regression models. Models were adjusted for demographics, lifestyle and anthropometric factors, reproductive history, gynecologic morbidity, and indications for use of pain medications (e.g. endometriosis, migraine headaches, antibiotic use as a proxy for fever/infection).
RESULTS: At baseline, 1279 (73%) women reported using greater than or equal to 1 pain-relieving medication in the past month. When compared with non-use of pain relieving medications, use of naproxen (aFR: 0.76, 95% CI: 0.61-0.93) and opioids (aFR: 0.81, 95% CI: 0.59-1.10) was associated with reduced fecundability. There was little evidence of association between fecundability and acetaminophen, aspirin, or ibuprofen. Similar results were observed for baseline and time-varying analyses. Among women younger than 30, acetaminophen use reported at baseline was associated with a 23% increase in fecundability (95% CI: 1.03-1.48); a slight inverse association was observed among women greater than or equal to 30 (aFR=0.87, 95% CI: 0.72-1.05).
CONCLUSIONS: Preconceptional use of pain-relieving medications may influence human fecundability, and associations may vary by active agent. Residual confounding by indication may partially explain these results, warranting further research.
