Macrolide taken during pregnancy may cause major birth defects: Study

The use of macrolide antibiotics during pregnancy is associated with an increased risk of major birth defects, according to a recent study.

The study, published in the BMJ, found that taking macrolide antibiotics during the first trimester increases the risk for any major malformation, specifically cardiovascular malformation, compared with penicillin-based antibiotics.

The researchers from the University College of London analysed data from 104,605 children born in the UK from 1990 to 2016 using the Clinical Practice Research Datalink (CPRD) with a median follow-up of 5.8 years after birth.

A further 82,314 children whose mothers were prescribed macrolides or penicillins before pregnancy, and 53, 735 children who were siblings of children in the study group acted as control (comparison) cohorts.

The study found major malformations in 186 children of 8,632 whose mothers were prescribed macrolides at any point during pregnancy and 1,666 of 95,973 children whose mothers were prescribed penicillin.

“Macrolide antibiotics are used to treat a wide variety of bacterial infections, and are among the most frequently prescribed antibiotics during pregnancy in Western countries,” said Heng Fan, Lead author, UCL Great Ormond Street Institute of Child Health.

“If the associations are shown to be causal, these findings suggest that an additional four children would be born with cardiovascular malformations for every 1,000 children exposed to macrolides instead of penicillins in the first trimester of pregnancy,” Fan said.

The study further revealed that macrolide prescribing in any trimester is linked with an increased risk of genital malformations and warned to take caution while using macrolides during pregnancy.

However, the authors underscored that “women should not stop taking antibiotics when needed,” but, if feasible, alternative antibiotics should be prescribed until further research is available.