Some antibiotics tied to birth defects

Researchers studying the association between birth defects and antibiotics use early in pregnancy-1 month before through the third month-have found a link between common drugs used to treat urinary infections and birth defects.

“Penicillins, erythromycins and cephalosporins, although used commonly during pregnancy were not associated with most of the birth defects we studied,” said Krista Crider, PhD, geneticist with the Centers for Disease Control and Prevention's National Center on Birth Defects and Developmental Disabilities and primary author of the study published in November’s Archives of Pediatrics and Adolescent Medicine. The CDC funded the research.

“For sulfonamides . . .and nitrofurantoins . . .we did see some associations with specific birth defects,” Dr Crider told Formulary.

Researchers analyzed data from more than 13,000 mothers whose infants had birth defects and nearly 5,000 women who lived in the same regions with healthy babies. The women were interviewed by phone from 6 weeks to 2 years after their pregnancies. Those who remembered taking antibiotics during the month before conception through the first 3 months of pregnancy were identified as exposed to antibiotics. The authors acknowledged that the women’s memories could have been faulty, a substantial weakness of the study. About one-third of the women who took antibiotics couldn’t remember the specific type of drug they took. It’s also unclear whether the birth defects were caused by the drugs or by the underlying infections being treated.

“This study adds to the safety profile of penicillins and erythromycins and provides additional information to help the medical community to choose the most appropriate antibiotic to treat bacterial infections in pregnancy and women who may become pregnant,” according to Dr Crider.