Oral Nystatin Safety in Pregnancy
Oral nystatin is acceptable and safe to use during pregnancy, with minimal systemic absorption and no established teratogenic risk in humans. 1, 2
Safety Profile and Guideline Recommendations
The European Respiratory Society/Thoracic Society of Australia and New Zealand explicitly states that oral and topical nystatin use is acceptable in pregnancy and lactation. 2 This recommendation is based on nystatin's minimal systemic absorption when used orally or topically, making it compatible with pregnancy throughout all trimesters. 2
- Nystatin is classified as FDA Pregnancy Category A when used topically or locally, indicating the highest level of safety compatibility with pregnancy. 2
- The European Respiratory Society confirms nystatin is "compatible" for use during pregnancy due to its minimal systemic absorption. 1
Human Safety Data
The available human evidence supports nystatin's safety profile:
- A large population-based case-control study in Hungary (1980-1996) examined 22,843 pregnancies with congenital abnormalities and 38,151 control pregnancies. 3 The study found that oral nystatin treatment during pregnancy presents little teratogenic risk to the fetus, with only 0.5% of case mothers and 0.4% of control mothers receiving nystatin (OR 1.2,95% CI 1.0-1.6). 3
- One potential association with hypospadias was noted in this study, but the authors concluded this requires further investigation and does not contraindicate use. 3
- A 1975 comparative study documented no birth defects in infants born to mothers treated with nystatin during pregnancy. 4
FDA Drug Label Information
The FDA label for oral nystatin states that animal reproduction studies have not been conducted, and it is not known whether nystatin can cause fetal harm when administered to pregnant women. 5 However, the label notes that nystatin should be given to pregnant women "only if clearly needed," which is standard conservative language rather than evidence of harm. 5
Clinical Context and Comparison
Nystatin is considered a first-line antifungal agent for pregnancy due to its minimal absorption. 6 This contrasts sharply with systemic azole antifungals:
- Fluconazole doses >150 mg daily should be avoided during the first trimester due to established teratogenic risk (craniosynostosis, dysmorphic facies). 1
- Ketoconazole has been shown to be teratogenic and/or embryotoxic in animals. 7
- For serious systemic fungal infections requiring systemic therapy during pregnancy, amphotericin B remains the treatment of choice, not oral azoles. 2
Practical Recommendations
- Use oral nystatin for oral or gastrointestinal candidiasis during pregnancy without hesitation. 1, 2
- For vaginal candidiasis, topical nystatin, clotrimazole, or miconazole are preferred first-line agents. 6
- When using nystatin on nipples during breastfeeding, remove excess cream before nursing. 2
- Nystatin is minimally absorbed and considered safe during lactation, though it is unknown whether it is excreted in human milk. 5, 7