Taking macrolide antibiotics during pregnancy is not associated with an increased risk of major birth defects, a cohort study in the BMJ has found (10 February 2021).
The researchers carried out a historical register-based cohort study of all recorded pregnancies in Denmark between 1997 and 2016. Antibiotic use was defined as at least one filled prescription for a systemic macrolide antibiotic, including azithromycin, clarithromycin, erythromycin, roxithromycin and spiramycin.
Overall, 13,019 women who were prescribed macrolides during pregnancy were compared with 51,515 women who were prescribed penicillin during pregnancy, as well as other comparative groups where antibiotics were not used during pregnancy.
In total, 457 infants were born with major birth defects to women who had used macrolides during pregnancy (35.1 per 1,000 pregnancies), compared with 481 infants who were born to women who had used penicillin (37.0 per 1,000 pregnancies). The risk of major birth defects was not significantly increased for women who had used macrolides during pregnancy compared with those who had used macrolides before becoming pregnant (RR 1.00, 95% confidence interval (CI) 0.88 to 1.14) or compared with those who did not use any antibiotics (RR 1.05, 95% CI 0.95 to 1.17).
“We found no significantly increased risk of any of the 12 organ specific subgroups of birth defects, including defects of the heart, and no evidence of significant associations for individual macrolides,” the authors concluded.
- 1Andersson NW, Olsen RH, Andersen JT. Association between use of macrolides in pregnancy and risk of major birth defects: nationwide, register based cohort study. BMJ 2021;:n107. doi:10.1136/bmj.n107