By Elizabeth Landau
Don't drink while you're pregnant, not even in moderation. It's wisdom that major medical groups such as the American College of Obstetricians and Gynecologists have repeatedly emphasized. But researchers are still looking into the specific effects of different quantities of maternal drinking on children.
A new study in the British Medical Journal is the latest to look at whether moderate drinking during pregnancy is associated with adverse effects on children. The researcher's measure for detrimental fetal neurodevelopment - children's ability to do various balance tasks at age 10.
Researchers found that mothers who drank between three and seven glasses of alcohol a week during pregnancy did not, on average, have children who had balance problems at age 10, and there were even some observed benefits. However, these are associations, not a proof that alcohol causes any outcomes.
This also doesn't mean that it's now generally OK to drink during pregnancy, experts said. There is no safe dose of alcohol that has been established for pregnant women, so best not to take a chance.
Researchers looked at 6,915 children who participated in the Avon Longitudinal Study of Parents and Children. These children had a balance assessment at age 10, and information on how much alcohol their mothers consumed was available.
Most of the mothers - about 70% - did not consume any alcohol during pregnancy. About 25% drank between one to two and three to four glasses a week, and about 5% drank seven or more glasses per week.
Researchers rated the children on various ways of balancing, including walking on a beam and standing on one leg for 20 seconds.
Researchers did not find evidence that alcohol consumed during pregnancy was detrimental to childhood balance. In fact, higher use of alcohol during pregnancy had some correlation with better outcomes of children particularly in the static balance measurements (balance without moving).
But wait - the study authors noted that higher total consumption of alcohol was associated with "social advantage" --- in other words, wealth and education. "Social disadvantage," meanwhile, was associated with binge drinking and abstinence.
Given that disparity in socioeconomic status is related to factors such as stress and health care, it could be that those were responsible for any benefits seen here - not the alcohol.
How to interpret?
The correlations in this study do not prove that alcohol caused any of the effects observed.
Previous studies in animals and humans have shown that alcohol exposure is related to a decrease in the size of the cerebellum, said Rajesh Miranda, associate professor of neuroscience and therapeutics at Texas A&M Health Science Center.
Dr. Robert Sokol, professor at Wayne State University School of Medicine, said this study is similar to others that have been published in the past. It doesn't mean that alcohol leads to better or worse outcomes; there could be other factors about the mothers who drank.
This is a large sample of people, but some women are more sensitive to alcohol than others, and some fetuses are more vulnerable to the effects of alcohol than others. You can't be sure what effect alcohol will have on any particular baby, so it's best to not take a chance, he said.
"We don't know a safe level, so the smartest advice is what the ACOG says: Don't drink," Sokol said. "If I were pregnant, I wouldn't drink."
CNN's Caitlin Hagain contributed to this report.