Nitrofurantoin, TMP-SMX Often Prescribed in Early Pregnancy for UTI

Potential risk for birth defects associated with use of sulfonamides and nitrofurantoin during pregnancy
Potential risk for birth defects associated with use of sulfonamides and nitrofurantoin during pregnancy

Nitrofurantoin and trimethoprim-sulfamethoxazole (TMP-SMX) are often prescribed to women with urinary tract infection (UTI) in their first trimester, despite guidelines recommending these agents be avoided in early pregnancy. Findings from this study were published in Morbidity and Mortality Weekly Report (MMWR).

According to a 2011 Committee Opinion from the American College of Obstetricians and Gynecologists, sulfonamides and nitrofurantoin may be prescribed to pregnant women in their first trimester only if other antimicrobial agents have been deemed clinically inappropriate. To investigate the effects of this recommendation, the Centers for Disease Control and Prevention (CDC) analyzed the Truven Health MarketScan Commercial Database to see which antibiotics were filled by pregnant women with UTIs in 2014 (n=34,864). 

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The results showed that among pregnant women with UTI, the most frequently dispensed antibiotics during the first trimester were nitrofurantoin (34.7%), ciprofloxacin (10.5%), cephalexin (10.3%), and TMP-SMX (7.6%). Fluoroquinolones and sulfonamides were more commonly dispensed to women within 90 days before the last menstrual period (LMP) than during any trimester of pregnancy, while nitrofurantoin, cephalosporins, and penicillins were more commonly dispensed during pregnancy than during the 90 days before LMP.

The authors conclude that "given the recommendations to avoid these medications in early pregnancy if possible and the fact that nearly 50% 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."

For more information visit CDC.gov.