( Boston , MA )The environmental toxin that presents the greatest danger to the highest number of unborn children today is alcohol. Fetal alcohol syndrome is one of the most common known cause of mental retardation in the United States. Despite increasingly wide public understanding of the devastating effects of heavy drinking by pregnant women, it remains too common and difficult to prevent. The September issue of the Harvard Mental Health Letter examines the multiple layers of this harmful trend.

It is not certain how much drinking is too much during pregnancy. According to one estimate, 30%-45% of women who consume six drinks a day or more throughout pregnancy will give birth to a child with fetal alcohol syndrome. However the style of drinking and its timing may also be important; a few binges early in pregnancy could be dangerous even if a woman consumes almost no alcohol after that.

Children with severe fetal alcohol syndrome have characteristic physical appearances and some develop heart, kidney, or urinary tract defects, poor muscle tone or joint articulation, and other physical disabilities. But in most cases, their emotional and intellectual limitations are more serious. Many are mildly retarded with an average IQ of 70. They may be hyperactive and distractible and exhibit significant behavioral problems. And as the September issue of the Harvard Mental Health Letter notes, studies show that most children and adults with fetal alcohol syndrome will eventually need mental health treatment.

Physicians are now urged to use a screening questionnaire to uncover pregnant and potentially pregnant women who abuse alcohol. Research shows that public warnings regarding pregnancy and drinking are usually ignored by heavy drinkers and alcoholics. Women who appear to need help may be given contraceptive advice, cognitive behavioral therapy, or a motivation interview in which they weigh the pleasure of drinking against the risk of birth defects. Heavy drinkers may require additional counseling, family support, or treatment.