Pregnant women have a higher risk of developing the yeast infection vaginal candidiasis due to an increased secretion of sex hormones; in the US, around 10% of pregnant women develop the condition.

Although intravaginal formulations of topical azole antifungals are the first-line treatment for pregnant women, oral fluconazole is often used.

However, there is a lack of safety information for the drug; in addition, previous studies have suggested evidence of a distinct pattern of craniofacial and skeletal birth defects in babies born to women treated long term with high-dose fluconazole during pregnancy.

Ditte Mølgaard-Nielsen, of the Statens Serum Institut in Copenhagen, Denmark, and colleagues evaluated the association between oral fluconazole exposure during pregnancy and the risk of spontaneous abortion and stillbirth.

In a nationwide cohort study, the team studied 1,405,663 pregnancies from 1997-2013 in Denmark.