Use of the antifungal agent terbinafine, either systemically or topically, during pregnancy does not appear to increase the risk of major fetal malformations or spontaneous abortion, researchers say.

In their large Danish registry study, covering 1.65 million pregnancies across two decades, 891 expectant women were exposed to oral terbinafine and 3174 to topical terbinafine.

Each of these women were matched to 10 other women in the database who had not used any antifungal medications during their pregnancy or in the year prior, the researchers reported in JAMA Dermatology.

The results showed that 3.8% of women exposed to oral terbinafine in the first trimester had a child that had a major malformation diagnosed in the first year of life — a figure identical to that for women with no exposure to the drug.