Taking a certain class of antibiotics while pregnant has been linked to severe infant birth defects, according to a study published in The BMJ.
U.K. researchers studied 104,605 children born from 1990 to 2016 whose mothers were prescribed one macrolide antibiotic (erythromycin, clarithromycin or azithromycin) or one penicillin antibiotic from the fourth week of pregnancy to delivery.
Researchers observed major malformations in 186 of 8,632 children whose mothers were prescribed macrolides, representing a rate of 21.55 per 1,000 births. Among the 95,973 children whose mothers were prescribed penicillins during pregnancy, 1,666 developed major malformations, a rate of 17.36 per 1,000 births.
Taking a macrolide antibiotic during the first trimester was associated with an increased risk of any major malformation compared with penicillin, specifically cardiovascular malformations. Also, macrolide prescriptions in any trimester was linked with an increased risk of genital malformations.