Pregnant women have long been bombarded with conflicting medical advice on the subject of alcohol. While many, especially in countries where wine is viewed as part of a healthy lifestyle, feel an occasional glass is safe, alcohol abuse has been linked to cognitive and developmental disorders in children, particularly fetal alcohol syndrome. Many doctors advise that the safest policy is no alcohol during pregnancy.
But a British study published in the International Journal of Epidemiology is raising new questions. The research found that not only can pregnant women safely drink a glass or two of wine per week, but that their children performed better three years after birth when compared to children of women who did not drink at all.
The research was conducted by the University College London, with the support of the University of Oxford and others. "The link between heavy drinking and the risk of fetal alcohol syndrome is well-established," wrote the authors, led by Dr. Yvonne Kelly of UCL's department of epidemiology and public health. "However, it is unclear whether low levels of drinking during pregnancy may convey harm for child health and development."
Kelly added that various United Kingdom national health institutes are inconsistent with advice regarding this behavior. "Very few studies have considered whether light drinking in pregnancy is a risk for behavioral and cognitive problems in children," said Kelly.
The researchers pulled data on 12,495 3-year-old children from the U.K. Millennium Cohort Study, a project following the health and well-being of children born between 2000 and 2002 in England, Northern Ireland, Scotland and Wales. Families were randomly selected from child-benefit rolls (every mother is entitled to a stipend from the government after each birth).
During pregnancy, the women completed questionnaires on alcohol consumption, among other topics. The Millennium researchers then returned to the households three years later and administered a series of cognitive and behavioral tests on the children. For the current research, Kelly and her team separated the results of those tests according to the patterns of drinking in the mothers.
They found that light drinking did not appear to result in an increase of behavioral difficulties or cognitive deficits. "Indeed, for some behavioral and cognitive outcomes, children born to light drinkers were less likely to have problems compared to children of abstinent mothers," she said. "Children born to heavy drinkers were more likely to have problems compared to children of mothers who drank nothing whilst pregnant."
The team found that children born to mothers who drank lightly—one to two glasses of wine a week—were 30 to 40 percent less likely to be hyperactive or display bad conduct, compared to mothers who abstained from alcohol during pregnancy. Children from mothers who drank lightly scored higher on vocabulary tests, for example, and could identify more shapes, colors, numbers and letters than children in the other categories. This result was consistent even when socioeconomic factors and other lifestyle choices such as the prevalence of smoking in the household were taken into account.
Moderate drinkers, defined as those who consumed three to six units of alcohol (3 to 6 glasses of wine, 3 to 6 shots of liquor or 1.5 to 3 pints of beer a week), had children who performed only marginally better on the same tests as children of nondrinking mothers. Children of mothers who drank more than seven units a week were more likely to exhibit a wide range of problems, most notably poor behavior and greater emotional instability.
Kelly believes that the socially advantageous standard of women who drank lightly may provide more of an explanation for the results rather than a dietary contribution from alcoholic beverages. "It may also be that light-drinking mothers tend to be more relaxed themselves and this contributes to better behavioral and cognitive outcomes in their children," she said.
Kelly added that the U.K. government is considering changing its alcohol policy to recommend complete abstinence during pregnancy, and that this research challenges that notion and merits further research into the subject.
Britain's National Health Service released a statement in response: "Official advice regarding drinking during pregnancy should not be ignored on the basis of this study. As there are known risks associated with heavy drinking during pregnancy and given that it is proving so difficult for studies to determine what lower limit is safe, women could just as well avoid alcohol during their pregnancy."