Study Finds New Antibiotics to Avoid During Pregnancy

Study Finds New Antibiotics to Avoid During Pregnancy

Pregnant and told you have to take antibiotics to fight an infection? You may want to pay attention to the name of the drug your doctor or midwife recommends.

According to a new study, certain antibiotics can increase the risk of birth defects in babies.

The researchers say the risk is small. Considering, however, that pregnant women commonly deal with infections, you may want to listen up.

“Infections during pregnancy are frequent and should be treated,” said Dr. Anick Bérard, the lead researcher and a professor at Montreal University, in a statement. “However, our study highlights safer options for treatment of infections, more specifically urinary tract infections (UTIs) or pulmonary infections, at least during the first trimester of pregnancy.”

Antibiotics to Avoid While Expecting

Which antibiotics were linked to birth defects? Clindamycin, doxycycline, quinolones, macrolides, and phenoxymethylpenicillin, the study in the British Journal of Clinical Pharmacology reports.

The good news: Amoxicillin, cephalosporins, and nitrofurantoin were three antibiotics studied that are believed to be safe. Nitrofurantoin is often prescribed for UTIs during pregnancy.

Earlier this year, Bérard linked classes of antibiotics such as quinolones, macrolides, tetracyclines, sulfonamides and metronidazole to a higher risk of miscarriage in early pregnancy. Erythromycin and nitrofurantoin were not linked to impairments. In 2015, she assessed azithromycin and clarithromycin and found no adverse impacts on child development.

Dr. Nanette Santoro, a gynecology and obstetrics professor at the University of Colorado School of Medicine, said patients at her fertility clinic are told not to take anything until they check with the doctors—even over-the-counter medications.

“The list of potentially problematic medications changes frequently and we want to be sure we have an opportunity to double check for them rather than take a risk,” she added.

What to Take, What to Skip

The Mayo Clinic reports that these antibiotics are typically deemed safe during pregnancy:

  • Amoxicillin
  • Ampicillin
  • Clindamycin
  • Erythromycin
  • Penicillin
  • Nitrofurantoin

The Mayo Clinic notes that tetracyclines such as doxycycline and minocycline can cause liver damage in the mother and discoloring in infants’ teeth.

Trimethoprim and sulfamethoxazole, which also are often used together to combat UTIs, may be associated with having a higher risk for birth defects – though they say there’s “no direct proof that these antibiotics cause birth defects” and call for more research, the Mayo Clinic reports.

Santoro said that clindamycin and macrolides are not on the “do not use” list for pregnancy, and quinolones are labeled to “use with caution.”

“The vast majority of antibiotics in pregnancy are for UTIs and most OB/GYNs use the ones on the ‘safe’ list,” she added.

Gerald Briggs, a pharmacist clinical specialist who wrote about this topic on, said that nitrofurantoin should be halted for urinary tract infections at about 36 weeks due to the risk it could destroy baby’s red blood cells. He said trimethoprim, which is found in Bactrim and Septra (used to treat UTIs) is not a good option during pregnancy because it blocks the effects of much-needed folic acid.

Of course, your health care provider should know all of this, but it never hurts to bring it up.

Cover image courtesy of Getty Images.