How much alcohol causes fetal alcohol syndrome?

FAS children are generally exposed to ponderously abusive amounts of alcohol. We're not likely to be confused by "moderation" here. Typical ingestion histories range from two or three six-packs of beer or the better part of a fifth of distilled spirits a day.

There have been no known cases of "full blown" FAS in children whose mothers consumed moderate amounts of alcohol; this is even more telling considering that patients virtually always understate their alcohol intake. There have been no cases reported in which wine was the source of ethanol.

Clearly, there may be compounding factors that stress the fetus. The typical profile of the FAS mother is a 30-plus-year old alcoholic in poor health, taking poor nutrition, smoking, living in a chaotic environment alone or in the company of a male alcoholic.

Most of the organ systems in the human fetus develop in the first two months after conception, and it is likely that most of the physical malformations occur from early exposure to episodic, very high levels of alcohol (often from binge drinking or sustained high levels with daily intoxication, the latter being the most common pattern).

Physical growth of the fetus occurs throughout pregnancy, and the small size of FAS babies likely relates to toxic effects upon cell growth throughout the nine months. Brain growth accelerates markedly in the third trimester and cessation of maternal alcohol abuse before this point can considerably reduce the neurological handicaps of FAS.