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Study Finds an Antibiotic Commonly Prescribed to Pregnant Women May Cause Birth Defects

An alarming new study from the CDC finds pregnant women are often prescribed drugs linked to birth defects.

Preg antibiotics 112 Syda Productions/Shutterstock

If you've ever had a UTI, you know they are no fun, and you want to get rid of them right away. Some antibiotics used to treat urinary tract infections shouldn't be given to women who are pregnant, though, because they have been linked to birth defects—but a new CDC study found that four in 10 pregnant women have been prescribed them anyway.

Why are pregnant women prescribed dangerous drugs?

The study looked at over 34,000 pregnant women with UTIs, using health insurance claims and pharmacy records to figure out what antibiotics they'd been prescribed. According to the research, about one in 10 pregnant women had a diagnosis of a UTI just before or during pregnancy. Three of 10 women with a UTI in early pregnancy filled a script for the antibiotic nitrofurantoin (also called Macrobid) and one in 10 filled a script for trimethoprim-sulfamethoxazole (a type of sulfonamide; also called Bactrim). Both of these drugs are considered unsafe in pregnancy.

Guidelines against these antibiotics in the first trimester were issued in 2011 (and revised in 2017) by the American College of Obstetricians and Gynecologists (ACOG) because they have been associated with heart and brain defects, cleft lip and palate, and other problems in babies. These recommendations say to use the medications in the first trimester only when no other suitable alternative antibiotics are available. Although ACOG says the research on the drugs' potential dangers has had mixed results, it's still best to err on the side of caution and avoid them.

But as evidenced by the CDC study's results, many healthcare providers shockingly don't seem to be aware of the recommendations against these antibiotics in pregnancy—or don't realize their patient is pregnant when prescribing the drugs to her. "Given the recommendations to avoid these medications in early pregnancy if possible and the fact that nearly 50 percent of pregnancies in the United States are unintended, it is important that health care providers of various specialties be aware of these recommendations and that they might be 'treating for two' when prescribing antibiotic treatments for UTIs to pregnant women and women who might become pregnant in the near future," the study authors write.

What to do if you get a UTI

UTIs themselves can be dangerous and should be treated—just with safer antibiotics. They're common in pregnant women, especially in the first trimester, as hormonal and physical changes in the body make the conditions ripe for bacteria to grow. If untreated, UTIs can lead to kidney infections, which can have complications including preterm labor and low birthweight.

If you have symptoms of a UTI, which include pain or burning when urinating and a feeling of having to go constantly, let your doctor know so you can be treated right away. But, it's equally important to let your healthcare providers know you're pregnant or that you're trying to become pregnant, so they can give you the appropriate meds. In addition, ask about the antibiotics you'll be receiving and read the prescription label so you can be sure what you're taking. When it comes to your health and the health of your future child, you need to be your own advocate.