KetoneAid recommends avoiding Hard Ketones if you’re pregnant or breastfeeding for liability reasons. I have not seen any scientific evidence suggesting that butanediol is detrimental to the mother’s health, but the founder of Hard Ketones suggested that fetuses and babies don’t have the enzyme required to break down the butanediol molecule. To be on the safe side, I’d avoid consuming Hard Ketones if you’re pregnant or breastfeeding.