Because alcohol affects so many sites in the brain, researchers have come to believe that alcohol is far worse for the developing fetus than any other abused drug.
Dr. Jacobson's study included cocaine users who also used varying quantities of alcohol. "We found more serious cognitive impairment in relation to alcohol than cocaine or other drugs, including marijuana and smoking," Dr. Jacobson said.
The damage done to fetuses often has been wrongly connected to cocaine, many experts say.
"The consensus, I think, at this point is that most of the adverse effects that had been reported due to cocaine and crack use were from alcohol use," said Dr. Kenneth R. Warren, the director of the office of scientific affairs at the National Institute on Alcohol Abuse and Alcoholism. "It is the leading cause of birth defects due to an ingested environmental substance in this country."