Fetal alcohol spectrum disorder (FASD) is an umbrella term used to describe fetal alcohol syndrome (FAS) and the less noticeable, but sometimes equally serious, fetal alcohol effects (FAE).

FASD is a permanent, and often devastating, birth-defect syndrome caused by maternal consumption of alcohol during pregnancy. Fetal alcohol exposure is regarded by researchers as the leading known cause of mental and physical birth defects, surpassing both spina bifida and Down syndrome, and producing more severe abnormalities than heroin, cocaine, or marijuana. It may be the most common preventable cause of birth defects in the United States.