The classic azole antifungal drugs affect steroidogenic activity in a human term placenta model.

During pregnancy there is an increased risk of vulvovaginal candidiasis that if left untreated is associated with pregnancy complications. First choice of treatment are over-the-counter azole antifungal drugs (AADs): miconazole, and clotrimazole, or prescription drug: fluconazole, which are suspected endocrine disruptive compounds. To investigate foetal exposure and endocrine disrupting effects of AADs on the human placenta, we added R-miconazole, S-miconazole, clotrimazole and fluconazole to the maternal reservoir of a dually recirculating ex vivo human term placental perfusion model. After three hours perfusion, AADs and steroids in perfusion media and placental tissue were quantified by LC-MS/MS, and real-time qPCR was performed to investigate gene expression of relevant steroidogenic enzymes in the placenta. We also investigated the distribution of AADs in the placenta using MS Imaging, and modelled interactions between AADs and the highly active steroidogenic enzyme, CYP19A1 (aromatase). Both enantiomers of miconazole, clotrimazole and fluconazole permeated the placenta reaching equilibrium between maternal and foetal compartments within 90 min. Miconazole and clotrimazole accumulated in placental tissue, whereas fluconazole reached a foetal compartment concentration of 50 % of added dose. We observed increased levels of androgens and decreased levels of oestrone in maternal and foetal perfusates, indicating inhibitory effects on placental aromatase activity, with the imidazoles, miconazole and clotrimazole, being more potent than the triazole fluconazole. MS imaging and molecular docking supported these findings. No significant changes in gene expression were observed for CYP11 A1, CYP19A1, and 3β-HSD after exposure to AADs. Overall, our study indicates that AADs affect placental endocrinology by inhibiting aromatase function.