Back in the 1970s, the dangers of drinking alcohol during pregnancy were largely unknown. As a result, many women consumed alcohol during pregnancy, even drinking heavily on occasion.

Since that time, studies have found fetal exposure to alcohol to be associated with impairments in attention, memory, intellect, judgment, and social behavior.

Researchers began a study in 1974 by recording the drinking habits of pregnant women. Now, 22 years later, they followed up to analyze the effects that prenatal alcohol exposure may have had on these women’s children. In an article published in the April 2003 Archives of General Psychiatry , researchers report that mothers who drank heavily even once during pregnancy put their children at significantly increased risk of developing drinking problems when they became young adults.

About the Study

From 1974 to 1975, researchers identified 500 women who were (on average) five months into their pregnancies. They interviewed these women to assess:

  • Alcohol consumption during pregnancy and before they knew they were pregnant
  • Heavy episodic drinking (five or more drinks on an occasion)
  • Exposure to other substances including caffeine, aspirin, antibiotics, marijuana and other illicit drugs
  • Family history of alcohol problems

Twenty-two years later, the researchers interviewed 433 children (now about 21 years old) of mothers who had been interviewed in the 1970s. The young adults were asked about their usual drinking patterns, whether and how often they drank five or more drinks at one time, and perceived negative consequences of their drinking (i.e. blackouts, passing out, tolerance). Based on this and other information the subjects were rated on the Alcohol Dependence Scale (ADS), which assesses the presence and severity of drinking problems and dependence symptoms.

The Findings

Eighty percent of the mothers had consumed alcohol during pregnancy and in the months before they knew they were pregnant. Thirty-one percent of these women reported at least one instance of heavy episodic drinking during pregnancy.

Of the 433 young adults, 82.9% said they were current drinkers. The remaining 17.1% were lifelong or current abstainers. Eight percent of the 433 offspring were found to have at least mild alcohol dependence, based on the ADS.

The researchers found that 14.1% of the young adults whose mothers drank heavily on one or more occasion during pregnancy had alcohol problems (ADS score greater than or equal to 10) at age 21 compared to 4.5% of the young adults whose mothers did not drink as heavily during pregnancy. This significant difference remained even when factors such as family history of alcohol problems, and prenatal exposure to nicotine and other drugs was taken into account.

How Does This Affect You?

The ages of 18 to 24 (the college years) tend to be the period of heaviest drinking for most people, even though most people who drink heavily at this time do not go on to have alcohol problems. On the other hand, people who do develop alcohol problems in later life usually begin drinking during adolescence or young adulthood. As a result, identifying young adults who are at greater risk for eventual alcohol problems could help them avoid that path.

Based on the ADS, the researchers in this study were able to distinguish between drinkers who were exhibiting “typical” college drinking behaviors and those with symptoms of alcohol dependence, such as passing out, blackouts, and becoming physically sick. The latter were significantly more likely to have had mothers who drank heavily on one or more occasions during pregnancy.

While it has long been known that heavy alcohol use during pregnancy may result in serious intellectual and behavior problems, this is the first time that it has been linked to alcohol dependency later in life even in the absence of these serious neurologic problems. This research further supports the advice that women should not drink while pregnant.