Evidence sparse that binge-drinking harms fetus

By Megan Rauscher

NEW YORK (Reuters Health) - There is no convincing evidence in the medical literature that binge-drinking on a single occasion during pregnancy, unlike chronic heavy drinking, has harmful effects on the developing fetus, researchers report.

However, there is some evidence of a possible harmful effect of prenatal binge-drinking on normal brain development, although the effects are "generally quite small," and further research is needed to confirm this, the researchers note in the Journal of Epidemiology and Community Health.

While consistent heavy alcohol drinking during pregnancy is known to be associated with birth defects and neurological problems in the offspring, it is less clear what impact binge-drinking, in the absence of regular heavy drinking, might have on the developing fetus.

Dr. Ron Gray of the University of Oxford and colleagues reviewed 14 relevant "observational" studies on binge-drinking in pregnant women or women trying to become pregnant. Binge-drinking was most commonly defined in the studies as drinking five or more alcoholic beverages on a single occasion (60 grams of alcohol, equal to 7.5 UK units).

According to Gray and colleagues, the reviewed studies contained no consistently significant effects of alcohol on any of the outcomes considered: miscarriage, stillbirth, intrauterine growth restriction, prematurity, birth weight, having a small baby at birth, and birth defects, including fetal alcohol syndrome and neurodevelopmental effects.

There was some suggestion that binge-drinking, particularly during the first 13 weeks of pregnancy, might impair normal brain development. The possible harmful effects observed included an increase in "disinhibited behavior," a reduction in verbal IQ, an increase in delinquent behavior and more learning problems and poorer performance.

The researchers note, however, that "the four studies that considered neurodevelopment were not without problems."

Summing up, Gray told Reuters Health that more study is needed into the effects of binge-drinking on the developing fetus. In the meantime, "pregnant woman should be advised to avoid binge-drinking," he said.

"However, from a clinical point of view, when pregnant women report isolated episodes of binge-drinking in the absence of a consistently high daily alcohol intake, as is often the case, it is important to avoid inducing unnecessary anxiety as, at present, the evidence of risk seems minimal," Gray noted.

SOURCE: Journal of Epidemiology and Community Health, December 2007.