Concern about maternal alcohol consumption began whith recognition of the Fetal Alcohol Syndrome(FAS), a series of infant abnormalities found in mothers who drank heavily during pregnancy.
Halmarks of FAS:
Abnormal Facial Features: Smooth philtrum (midline depression between upper lip and nose) and Small eye openings.
Mental/Intellectual issues: Mental Retardation, brain damage
Functional disorders: Disability in learning, communication/language, intelect, concentration, behavioral issues.
Unfortunately, one cannot always immediately recognize subtle defects as outlined above, especially in mild cases of FAS in which the face appears normal.
This is the basis for recommending abstinence or near abstinence for pregnant women. There is simply no way to predict or, after birth, clearly establish the degree of harm that maternal alcohol ingestion has done to the child.
On a positive note, however, it is known that all issues of FAS are dose-related. The degree and frequency of maternal alcohol use are important. For example, there is no medical reason whatsoever for a mother to beat herself up if she has an occasional glass of wine or cocktail during her pregnancy.
As with many things in life, moderation is the key.