Common antibiotics tied to increased risk of birth defects, study suggests

By Gabriela Baron

The use of commonly prescribed antibiotics during the first trimester of pregnancy is tied with higher risk of birth defects, a new study suggests.

The study, published Wednesday in the British Medical Journal, found an increased risk of birth defects in the children of mothers who were prescribed macrolides during the first three months of pregnancy compared to those who were prescribed with penicillin.

Macrolide antibiotics include erythromycin, clarithromycin, and azithromycin. They are used to treat infections such as pneumonia, bronchitis and urinary, skin, and sexually transmitted disease.

The researchers studied over 180,000 children whose mothers were prescribed either penicillin or one of the macrolide antibiotics. They found that those who took macrolides had a 55 percent increased relative risk of having a baby with a major defect involving nervous, cardiovascular, gastrointestinal, genital, or urinary system.

"Our findings suggest that it's better to avoid macrolides if other antibiotics can be used," said Heng Fan, lead author of the study.

However, the researchers clarified that the risk did not increase for women prescribed macrolides before pregnancy or those who took them later in pregnancy.

Antibiotics, they noted, were not associated with an increased risk for cerebral palsy, epilepsy, ADHD, or autism.