I already allowed for that case; I said (several levels upthread) if there's a benefit to the mother that outweighs the risk of harm to the child, then the alcohol use is justified.

That said, AFAIK whatever benefits have been found for alcoholic beverages are not due to the alcohol, but to some other substance that happens to be in the beverage (for example, antioxidants in red wine). If there is a way to get the other substance without the alcohol, that would seem to be preferable since it eliminates the risk without sacrificing the benefit.