Children whose mothers have one or two drinks per week during pregnancy are not at any greater risk for developing behavioral or cognitive problems than children whose mothers abstained completely, according to a new study from British scientists.

Researchers used data from 11,513 children who were part of the U.K. Millennium Cohort Study. They surveyed mothers on the amounts of alcohol they consumed during pregnancy, and followed up with the children at ages 9 months and 3 and 5 years. During home visits, behavior assessments were done with parents, and cognitive tests were done on the children.

The researchers previously published their results after assessments on the then-3-year-old children, showing no disadvantage for those whose mothers drank lightly during pregnancy. The new study addressed concerns that the effects of prenatal alcohol consumption would show up later in a child's life.

"The findings of this paper and our previous work suggest that, up to the age of 5 years, there is no increased risk of poor socioemotional or cognitive developmental outcomes in children born to mothers who drank not more than 1 or 2 units of alcohol per week during pregnancy," said the authors, who were led by Yvonne Kelly of the department of epidemiology and public health at University College London.

Children born to light drinkers were actually found to perform better on cognitive tests than mothers who abstained entirely, but those differences were erased when socioeconomic status was taken into account.

Drinking during pregnancy has been an issue with some debate. While heavy drinking during pregnancy has been shown to harm the fetus, the effects of small amounts of alcohol have been less clear. A similar debate has occurred with drinking while breastfeeding.

Many women follow the advice that some recommend — without knowing a safe dose, women should avoid alcohol altogether while pregnant.

However, in 1991, Drs. Joel Alpert and Barry Zuckerman of the Boston University School of Medicine wrote an analysis of studies for the journal Pediatrics in Review that stated, "Our conclusion is that there is no measurable or documented risk from this level [two or fewer drinks per day] of drinking during pregnancy. Therefore, by urging well nourished pregnant women to abstain from alcoholic beverages, we may be turning our attention away from negative health behaviors of far greater danger than consuming a glass of wine or its alcoholic equivalent."

The study results were published Oct. 5 in the Journal of Epidemiology and Community Health, from the British Medical Journal.

 This article was provided by MyHealthNewsDaily, a sister site to LiveScience.