Macrolide use in pregnancy tied to higher risk of birth defects

The study, published this week in the BMJ, looked at data on more than 100,000 children born in the United Kingdom from 1990 to 2016 to mothers who were prescribed macrolides or penicillins at any time during their pregnancy. The results showed that the association between risk of any birth defect, specifically heart defects, and macrolide use during the first trimester was significantly higher than it was for penicillin use.

Although the findings are observational and do not establish that macrolide antibiotics cause birth defects, they add to growing concerns about use of the drugs during pregnancy. Macrolides are widely used to treat infections in pregnant women with suspected penicillin allergies, but research has shown associations between macrolides and increased risk of heart arrhythmia and cardiovascular mortality, as well as miscarriage in pregnant women.

"Our findings suggest it would be better to avoid macrolides during pregnancy if alternative antibiotics can be used," study co-author Ruth Gilbert, MD, PhD, a professor of clinical epidemiology at University College London's (UCL's) Great Ormond Street Institute of Child Health, said in a university press release.