CDC: More research needed about prenatal opioid exposure and birth defects

Literature review calls for stronger studies in light of current opioid crisis

Opioid use during pregnancy may be linked to various birth defects, but much of the research published in the literature is older, flawed in methodology, or not generalizable, thus highlighting a need for new studies, say researchers at CDC’s Treating for Two: Safer Medication Use in Pregnancy initiative.

In a paper published online in Pediatrics, the researchers reviewed 68 studies about prenatal opioid exposure and birth defects. Of these, 46 had an unexposed comparison group, 15 had an exposed comparison group (i.e., comparing methadone exposure with other opioid exposures), and 7 were descriptive.

Although many of the studies suggested a positive association between prenatal opioid exposure and birth defects like oral clefts, congenital heart defects, and clubfoot, only 30 of them included statistical tests to measure that association. Furthermore, 35 of the studies were published before 1999—before the current opioid epidemic. The researchers noted there were no randomized control trials and few high-quality observational studies, while acknowledging that’s a common limitation of studies about pregnancy and medication.

In their conclusion, the researchers called for well-designed studies with unexposed comparison groups that estimate measures of association, and they cautioned health professionals to carefully evaluate the risks and benefits of opioid therapy when making decisions about treatment in reproductive-aged and pregnant women.