A woman's heavy episodic drinking during pregnancy triples the odds that her child will develop alcohol-related problems at age 21, according to a new study that has been tracking young adults since before their birth.

April 12, 2003

The paper, published today in the April issue of the Archives of General Psychiatry, points to fetal alcohol exposure as a risk factor in a person developing alcohol-related problems at 21. This relationship persists even when other demographic factors, including family history of alcohol problems, prenatal exposure to nicotine and other drugs, and other aspects of the family environment, are taken into account, said the University of Washington's John Baer and Ann Streissguth, the paper's lead authors.

Baer is a research associate professor of psychology at the UW and education coordinator at the Addiction Treatment Center at Veteran's Administration Puget Sound Medical Center. Streissguth is a UW professor of psychiatry and behavioral sciences.

The current paper is part of an ongoing study of factors associated with a healthy pregnancy and their long-term impact on development.

"It appears that exposure to alcohol during pregnancy can predict the amount of alcohol problems that a child will have in adulthood," said Baer. "It takes us a step further in understanding why some people have alcohol problems.

"We are trying to understand what causes some people to drink and get in trouble and why others don't. We found that 14 percent of the young adults who were prenatally exposed to one or more episodes of five or more drinks had alcohol problems at age 21 compared to just 4.5 percent who were not as heavily exposed to alcohol.

"This is not a one-to-one relationship, but a mother's drinking elevates the risk of her offspring having alcohol problems."
The paper's findings also contradicted other recent findings connecting prenatal nicotine exposure to adolescent alcohol use.

"Other studies have linked nicotine exposure with problems among adolescents, but we did not find that," said Baer.

"We tested to see if other factors might account for the relationship between fetal exposure and offspring drinking problems 21 years later. In addition to nicotine exposure, we examined gender, family history of alcohol problems and even drinking in the family as the child was growing up. Although these factors are also related to drinking problems found in the young adult offspring, they did not fully account for the effects of prenatal alcohol exposure."

When the study began in the mid 1970s, maternal drinking during pregnancy was common. Eighty percent of the women in the study drank alcohol during pregnancy and in the months before they knew they were pregnant. Thirty-one percent reported heavy episodic drinking – five or more drinks on an occasion – during pregnancy. The women were primarily white, middle class and well educated, but the subjects reflected the demographics of the community at the time.

Twenty-two years after the initial prenatal interviews, 433 families were reinterviewed and filled out questionnaires for the paper reported on today. There were slightly more males, 52 percent, among the total offspring. At age 21, 83 percent of the subjects reported themselves as current drinkers and 17 percent said they were lifelong or current alcohol abstainers. Eight percent of the young adults exhibited symptoms of at least mild alcohol dependence.

The college years, ages 18 to 24, typically are considered to be the period of heaviest drinking for most people. Yet Baer cautioned that most people who drink heavily at this time do not go on to develop alcohol problems later in life. However, those with persistent alcohol problems in mid-life typically begin drinking during adolescence and young adulthood. Identifying those young adults who are at risk for lifelong problems is a central focus of the research.

The researchers will continue to follow the families in the study to see if fetal alcohol exposure predicts more severe alcohol problems at later ages in adulthood. They also are trying to understand what it is about fetal alcohol exposure that puts people at risk for alcohol problems.

"This research also gives further support to the idea that women should not drink while they are pregnant," said Streissguth. "This policy is pretty well established today, but it wasn't when we began this work."

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The study is funded by the National Institute of Alcohol Abuse and Alcoholism. Co-authors of the study are Paul Sampson, a UW research professor of statistics; Helen, Barr, a UW research scientist in psychiatry and behavioral sciences; and Paul Connor, UW acting assistant professor of psychiatry and behavioral sciences.