Antibiotics: Now Safe in Pregnancy

Whether a pregnant woman could take antibiotics for things like UTIs was up for debate, but a new study says a group of controversial antibiotics are actually OK.

Antibiotics: Now Safe in Pregnancy gpointstudio/Shutterstock

When you're sick during pregnancy, one of the hardest decisions you're faced with is whether you should take medicine—and if so, which ones? Although penicillin has been accepted as safe for unborn babies, the effects of other antibiotics used to treat infections like UTIs—a common affliction of pregnant women—were less certain. But, a new study published in the journal Pharmacoepidemiology and Drug Safety is providing new clarity on some antibiotics whose safety was previously questioned.

No risk of birth defects

The researchers investigated whether there was any link between taking macrolides, including azithromycin, clarithromycin and erythromycin, during pregnancy and having a baby with birth defects. Looking at data from over 135,000 pregnant women in the Quebec Pregnancy Cohort, they compared the outcomes of those who'd taken macrolides, those who'd taken penicillin, and those who hadn't taken any antibiotics. "We did not find a statistically significant association between macrolide use during pregnancy and the risk of malformations," study author Anick Bérard, Ph.D., a professor in the Faculty of Pharmacy at the University of Montreal and a researcher at its affiliated CHU Sainte-Justine hospital, tells Fit Pregnancy. "This is reassuring when treating infections during pregnancy."

These results echo other recent studies that have showed macrolides are safe in pregnancy—the exception being a 2005 Swedish report that found pregnant women who took erythromycin had twice the risk of having a baby with a heart defect. "This led the Swedish and Norwegian regulatory medicines agencies to issue a warning against its use during the first trimester of pregnancy," Bérard says, although no warnings were issued in the US. The FDA classifies azythromycin and erythromycin, as well as penicillin, as category B drugs, which means they have been shown to be safe in animal studies. Clarithromycin is category C, which means it has been shown to have negative effects in animals. Neither group has had well-controlled studies in humans.

Dangers of untreated infections

After the Swedish study, "debate remained on whether it is the infections, or the macrolides used to treat them, that put women and their unborn child at greater risk of adverse pregnancy outcomes, including birth defects," Bérard says. In fact, not treating an infection in pregnancy in an attempt to avoid antibiotics might actually pose a greater risk to baby. Pregnant women are prone to infections because their immune systems are weaker, and leaving them untreated could lead to even more serious complications—for example, a UTI could become a kidney infection. Given that serious health issues in mom mean more danger for baby, including preterm labor and low birth weight, getting treated is important. "Almost 40 percent of pregnant women will use at least one antibiotic at some point in time during pregnancy," Bérard says. Her study "has great public health implications given the high frequency of infections during pregnancy."

If you get sick during pregnancy and are concerned about taking antibiotics, talk with your doctor to weigh the pros and cons, and ask about the specific antibiotic that you're prescribed. "Larger studies are still required to determine the risks of less frequently used macrolides," Bérard says. Although the results of the study were encouraging, "each woman is different and a thorough risk/benefit analysis should be done on an individual basis."