Can I take spironolactone while pregnant or breastfeeding?

Pregnancy: Teratogenic effects. Pregnancy Category C. Teratology studies with spironolactone have been carried out in mice and rabbits at doses of up to 20 mg/kg/day. On a body surface area basis, this dose in the mouse is substantially below the maximum recommended human dose and, in the rabbit, approximates the maximum recommended human dose. No teratogenic or other embryotoxic effects were observed in mice, but the 20 mg/kg dose caused an increased rate of resorption and a lower number of live fetuses in rabbits. Because of its antiandrogenic activity and the requirement of testosterone for male morphogenesis, spironolactone may have the potential for adversely affecting sex differentiation of the male during embryogenesis. When administered to rats at 200 mg/kg/day between gestation days 13 and 21 (late embryogenesis and fetal development), feminization of male fetuses was observed.

Prescribing label, section “Pregnancy” (opening excerpt): Spironolactone (oral), NuCare Pharmaceuticals, Inc. Read the full section on DailyMed. Quoted verbatim; US labels are written for US prescribers and patients.

Limited data indicate that spironolactone is poorly excreted into breastmilk. Case of mothers breastfeeding during spironolactone therapy reported no adverse effects in infants. Spironolactone appears to be acceptable to use during breastfeeding.

“Summary of Use during Lactation”, LactMed record “Spironolactone” (LM246), quoted verbatim. Everything LactMed reports about Spironolactone while breastfeeding.