Alcohol use or abuse by the pregnant woman subjects her to the same range of risks that alcohol has in the general population. However, it poses extreme and unique risks to the fetus and is associated with fetal alcohol syndrome. Timing of alcohol use during pregnancy is also of importance. Alcohol use during the first trimester is more damaging than during the second trimester which is, in turn, more damaging than use in the third trimester.
Alcohol ingested by a pregnant woman easily passes across the placental barrier to the fetus.
Because of this, drinking alcohol can adversely affect the development of the baby. The incidence of fetal alcohol syndrome varies from 1 out of 1,500 to 1 out of 600 live births. This wide range is related to differences in drinking practices. However, increasing amounts appear to cause increased problems in a linear fashion. Abstinence from alcohol during pregnancy absolutely prevents fetal alcohol syndrome.