Updated: FDA Investigates Study Showing Yeast Infection Drug Increases Risk of Miscarriage

Posted 26 April 2016 | By Zachary Brennan 

Updated: FDA Investigates Study Showing Yeast Infection Drug Increases Risk of Miscarriage

The US Food and Drug Administration (FDA) said Tuesday that it’s evaluating the results of a Danish study that found a possible increased risk of miscarriage with the use of Diflucan (fluconazole), a Pfizer treatment for yeast and other fungal infections.

The FDA-approved label for Diflucan says that current data do not suggest an increased risk of problems during pregnancy or abnormalities in developing babies when women are exposed to a single 150 mg dose of oral fluconazole to treat vaginal yeast infections.

“However, high doses of oral fluconazole (400-800 mg/day) taken by pregnant women for much longer than a single dose have resulted in reports of abnormalities at birth. In the Danish study, most of the oral fluconazole use appeared to be one or two doses of 150 mg,” FDA added.

The study cited by FDA was published in January in JAMA evaluated a cohort of 1,405,663 pregnancies from a nationwide register in Denmark between 1997 and 2013, which evaluated oral fluconazole–exposed pregnancies compared with up to four “unexposed pregnancies matched on propensity score, maternal age, calendar year, and gestational age.” 

The Danish researcher concluded: “In this nationwide cohort study in Denmark, use of oral fluconazole in pregnancy was associated with a statistically significant increased risk of spontaneous abortion compared with risk among unexposed women and women with topical azole exposure in pregnancy. Until more data on the association are available, cautious prescribing of fluconazole in pregnancy may be advisable.” 

FDA says it’s reviewing this study and additional data and will communicate final conclusions and recommendations when the review is complete.

In 2011, FDA warned the public that chronic, high doses (400-800 mg/day) of Diflucan “may be associated with a rare and distinct set of birth defects in infants whose mothers were treated with the drug during the first trimester of pregnancy,” though FDA also said that risk “does not appear to be associated with a single, low dose of fluconazole 150 mg to treat vaginal yeast infection (candidiasis).”

In Tuesday’s announcement, FDA calls on health professionals to be aware that the Centers for Disease Control and Prevention guidelines recommend only using topical antifungal products to treat pregnant women with vulvovaginal yeast infections, including for longer periods than usual if these infections persist or recur.

Pfizer spokeswoman Rachel Hooper told Focus: "Fluconazole [is] a prescription medicine for the treatment of a variety of fungal infections, has a well-established benefit risk profile supported by more than 25 years of patient experience. 


"We are committed to patient safety and, as with all our medicines, the benefit/risk profile of fluconazole is continually monitored on a regular basis and as new information becomes available through the literature, clinical studies, spontaneous reports, and safety database searches, to ensure that the benefits and risks are accurately described in the product label, as approved by the FDA and other regulatory agencies around the world."

Editor's note: This story was updated on 4/27/16 to include Pfizer's comment.

Fluconazole (Diflucan): Drug Safety Communication - FDA Evaluating Study Examining Use of Oral Fluconazole (Diflucan) in Pregnancy

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