Using the oral antifungal medication fluconazole during pregnancy has been associated with an increased risk of spontaneous abortion. That’s the findings of a new large-scale study published in JAMA, which assessed over 1.4 million pregnancies in Denmark.

The researchers found a significantly increased risk of spontaneous abortion in women taking oral fluconazole when compared to unexposed women, and those who used topical antifungal treatments instead. Fluconazole-exposed pregnant women were measured against unexposed women of the same maternal and gestational age.

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Of 3315 women exposed to oral fluconazole from 7 through 22 weeks’ gestation, 147 (4.43%) experienced a spontaneous abortion, compared with 563 (4.25%) out of 13,246 unexposed matches. Among 5,382 women exposed to fluconazole from gestational week 7 to birth, 21 (0.39%) experienced a spontaneous abortion, compared with 77 (0.35%) among 21,506 unexposed matches.

However, there was no significant association between fluconazole exposure and stillbirth. Using topical azole as a comparison; 20 out of 4,301 women exposed to fluconazole had a stillbirth vs. 22 out of 4,301 who used topical azoles.

“Until more data on the association are available, cautious prescribing of fluconazole in pregnancy may be advisable,” said the authors. It is estimated that vaginal candidiasis (yeast infection) effects 10% of pregnant women in the USA. Although intravaginal formulations of topical azole antifungals are first-line treatment for pregnant women, oral fluconazole is often used despite limited safety information. 

For more information visit JAMA.