Prenatal exposure to alcohol had not been studied as a potential cause or risk factor for alcohol abuse prior to the current study. However, previous work had shown that adults who had been adopted and who had had fetal exposure to alcohol reported more symptoms of alcohol, nicotine, and other drug dependence than adopted adults who did not have a record of alcohol exposure in utero.

Ann P. Streissguth, Ph.D., and her American colleagues obtained information from 433 families and children of mothers who were first studied in 1974-1975 at roughly 5 months gestation. Maternal drinking during pregnancy was assessed along with measures of smoking, use of caffeine and other drugs, and demographic factors.

Family history of alcohol problems was determined through interviews with the parents when their children were 14 years old and updated when the children were 21 years old. Parental alcohol and drug use were assessed at 7 time points over 21 years with the first measurement during the mother's pregnancy. When the children were 21 years old, they provided self-reports on drinking habits, including quantity and frequency of alcohol consumption, and they completed the Alcohol Dependence Scale as a measure of alcohol-related problems and dependence.

Of the 433 children, 359 (82.9 percent) at the 21-year follow-up reported themselves as current drinkers, whereas only 74 (17.1 percent) called themselves life-long or current abstainers. The current drinkers reported consuming alcohol an average of 5.77 times per month with an average of 3.79 drinks per time. The finding that 36.5 percent of current drinkers reported drinking 5 or more drinks on at least one occasion during the past month was consistent with data from national studies. Of the 433 adult children, 35 (8.1 percent) scored at or above 10 on the Alcohol Dependence Scale, indicating at least mild alcohol dependence.

"Prenatal alcohol exposure is significantly associated with alcohol-related problems assessed in offspring at 21 years of age," the researchers wrote. "This relationship remains when we account for sex, other demographic factors, family history of alcohol problems, prenatal exposure to nicotine and other drugs, and other aspects of the family environment."

"With the results from recent studies of adoptees, this study suggests that prenatal exposure to alcohol should be considered within the matrix of etiological factors for alcohol use disorders," they concluded.