New study into effects of taking Macrolide antibiotics during pregnancy

There has been some national coverage today regarding a study published by the BMJ, suggesting that Macrolide antibiotics in pregnancy can be linked with birth defects when taken during the first trimester. It is important to understand the outcomes highlighted by this study, so pregnant women do not become alarmed by some of the headlines that are emerging.

Macrolide antibiotics (including erythromycin, clarithromycin, and azithromycin) are used to treat common bacterial infections and are considered alternatives for patients with penicillin allergy.  

Based on the results of this study, using an alternative antibiotic wherever possible in early pregnancy is preferable. However, if macrolides are the only treatment option, women should be reassured that the risk of a problem is low.

Researchers from Great Ormond Street Institute of Child Health said that these antibiotics should be “used with caution during pregnancy and, if possible, feasible alternative antibiotics should be prescribed until further research is available.” Pat O’Brien, vice president of the Royal College of Obstetricians and Gynaecologists, said that pregnant women who have had antibiotics prescribed should not stop taking them “based on this latest study alone” and should instead speak to their doctor about any concerns.  

"If you've got a bacterial infection, it's really important to take antibiotics because infection itself can be really damaging to the unborn baby."
University College London Professor, Ruth Gilbert, one of the authors of the study

Although the study was “high quality”, this type of study “can never definitively prove a drug causes birth defects” said Sarah Stock, senior clinical lecturer in maternal and fetal medicine at the University of Edinburgh’s Usher Institute.

If you are concerned about any medication you have taken or are currently taking, please contact your GP or midwife so they can advise and reassure you.