Miconazole

Pregnancy

Miscarriage: Rosa et al. 1987 reported a relative risk of 1.4 (95% CI 1.2 to 1.5) for first-trimester miconazole use, but the authors called the result a signal for further study, not definitive. Rotem et al. 2018 studied 65,457 pregnancies, including 633 with vaginal miconazole exposure through week 20; the adjusted HR was 1.34 (95% CI 0.99 to 1.80). Birth defects: Czeizel et al. 2004 reported no increase in a case-control study with 24 exposed cases and 46 exposed controls (crude OR 0.9, 95% CI 0.6 to 1.6). Rotem et al. 2018 studied 313 first-trimester vaginal miconazole exposures and found a musculoskeletal signal that was not present after propensity matching. Kunitoki et al. 2025 studied 12,472 Japanese pregnancies with vulvovaginal candidiasis; first-trimester miconazole exposure was not associated with higher major-malformation odds than clotrimazole (wOR 0.887, 95% CI 0.497 to 1.581). These studies have different designs and comparators and do not establish zero risk. Newer endpoints: Andreasen et al. 2025 assessed 35 women reporting topical antifungal use and measured hormones and anogenital distance, without reporting miconazole-specific results. Mola et al. 2026 followed 589 mother-child pairs; 24 women reported miconazole use, but drug-specific human subgroup analyses were not performed. Mola's miconazole-specific experimental findings came from rats and fetal adrenal cultures, not clinical human outcomes. Absorption: in 20 nonpregnant women, a 1,200 mg vaginal suppository produced measurable serum miconazole, so absorption is low but not zero. MotherToBaby says most studies at doses below 400 mg per day did not find more birth defects; those findings do not establish results for other routes or doses.

Breastfeeding

MotherToBaby says breastfeeding studies of miconazole are absent and expects only small amounts to pass into milk after topical or vaginal use. LactMed's September 2022 revision says relevant published maternal milk levels, infant levels, and infant effects were not found; its conclusion that infant harm is unlikely is based on poor skin and vaginal absorption and poor oral bioavailability. A 2012 randomized trial enrolled 151 breastfeeding women with damaged nipples and compared lanolin with an all-purpose ointment containing mupirocin, betamethasone, and miconazole; it measured maternal nipple and breastfeeding outcomes, not milk transfer or infant effects, and cannot isolate miconazole. The Breastfeeding Network describes topical miconazole as compatible with breastfeeding. These findings do not establish infant exposure or outcomes for oral or systemic miconazole.

What was tested

The pregnancy evidence includes a 1987 prescription-record study of miscarriage, a 2004 case-control study of birth defects, two 2018 population cohorts, a 2025 Japanese claims cohort, and two newer cohorts that measured hormones or anogenital distance after antifungal exposure. The 2025 Odense cohort had 35 topical-antifungal users and did not provide miconazole-specific outcomes. The 2026 cohort included 24 reported miconazole users among 589 mother-child pairs but did not perform drug-specific human subgroup analyses; its miconazole-specific experimental findings came from rats and fetal adrenal cultures, not clinical human outcomes. Breastfeeding evidence includes no relevant miconazole milk-level or infant-effect data in LactMed and one maternal-outcome trial of a multi-ingredient ointment. No randomized pregnancy trial of miconazole was identified.