Fetal Alcohol Syndrome is caused by a mother's consumption of alcohol during pregnancy. It can result in permanent birth defects and is one of the most common causes of mental retardation. The diagnosis requires confirmed prenatal alcohol exposure as well as characteristic facial features, growth problems, and central nervous system abnormalities. While any alcohol use during pregnancy can potentially harm the fetus, the risks are greater with frequent or binge drinking. There is no known safe amount of alcohol, and effects can range from subtle learning disabilities to full Fetal Alcohol Syndrome.