Fetal alcohol syndrome (FAS) is the most common known preventable cause of mental impairment. Babies with FAS have distinctive changes in their facial features and they may be born small. The brain damage that occurs with FAS can result in lifelong problems with learning, memory, attention, and problem solving. These alcohol-related changes in the brain may be present even in babies whose appearance and growth are not affected. It is not known if there is any safe drinking level during pregnancy; nor is there any stage of pregnancy in which drinking—at any level—is known to be risk free
