If alcohol were to do damage during 3rd week of pregnancy what would it be? based on 2-4 glasses of wine per day during 3rd week only.

Difficult to say: Maybe none. There is a wide spectrum of disorders and abnormalities that can occur when mothers consume alcohol. The big concern is that it affects the developing brain, and the fetus brain is developing throughout the pregnancy. That's why the Fetal Alcohol Syndrome Association has a campaign that says " Not A Drop". We really don't know of safe levels of alcohol consumption.