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Some Common Antibiotics Linked To Birth Defects

Nov 3, 2009 | Parker Waichman Alonso LLP

A large study on the effects of antibiotics used during pregnancy and birth defects has been released. The Associated Press (AP) reported that the emerging study—the first of its kind to review the use of antibiotics during pregnancy—found a link between mediations for urinary tract infections and birth defects. The study appears in this month’s issue of Archives of Pediatrics and Adolescent Medicine, said the AP.

The AP added that penicillins, which are often prescribed in early pregnancy, appear to cause the least problems. Of note, bacterial infections can be problematic for a fetus if not treated, so antibiotics should not be avoided, but should be discussed with treating physicians, said the AP.

The study found that women who gave birth to infants with birth defects were likelier than women who gave birth to healthy children to report having taken two specific types of antibiotics during their pregnancy: Sulfa drugs, such as Thiosulfil Forte and Bactrim, and nitrofurantoins, which are urinary germicides branded under names such as Furadantin and Macrobid, said the AP. The study provided the first association between medications for urinary tract problems and birth defects, said Krista Crida, study lead and a geneticist with the U.S. Centers for Disease Control and Prevention (CDC), said the AP. The CDC funded the research. "Additional studies are going to need to be done to confirm these findings," said Crida, quoted the AP.

According to the AP, the antibiotics involved were introduced well before the U.S. Food and Drug Administration (FDA) and the agency’s requiring more intense safety testing, something that occurs today and involves testing to ensure medications are safe for expectant mothers and their unborn babies. Because the testing did not take place on a wide number drugs currently used, including antibiotics, no antibiotics have ever received the agency’s highest grade, an “A,” said the AP.

Sulfa drugs are considered among the oldest antibiotics and have been linked to adverse reactions in animal testing during pregnancy, said the AP. Sulfa medications were linked to rare brain (such as anencephaly) and heart issues as well as shortened limbs, while heart problems and cleft palate were associated with nitrofurantoins, reported the AP. The medications increased the birth defect risks two- and three-fold.

The research looked at over 13,00 mothers whose babies were born with birth defects and about 5,000 women who gave birth to healthy babies, said the AP; all of the women came from the same general region.