We know that consuming alcohol while pregnant can lead to alcohol related birth defects. I have read that physicians in Ancient/Medieval times were somewhat aware of these effects, but why do we not hear of more cases attributed to alcohol related birth defects? Also, alcohol was still consumed by many pregnant woman during these times, why do we not have more accounts of child defects/abnormalities?
Just how much alcohol puts an unborn baby at risk of FAS is really more of a medical question than anything, but the matter of pre-modern fetal alcohol syndrome has come up before, and this thread with input from u/SpicyBaconator and u/Noble_Devil_Boruta is particularly relevant.
Also, I'd be cautious of assuming alcohol consumption was pretty high back then, as I usually see this question presupposing that pre-modern people drank lots of alcohol to avoid bad water. OP, if you're starting from that premise, I have to tell you it's a false one - got a wholly different copypaste for that, if that's the case.