Is it really safe to drink during pregnancy? Not exactly, experts say

By Deborah Kotz, Globe Staff

Many pregnant women who heard the news this week that moderate amounts of alcohol won’t harm their fetus may be wondering whether they can safely sip a glass of champagne at a friend’s wedding or have a Coors light at a Red Sox game. Is the pendulum on alcohol finally swinging in the direction of caffeinated coffee -- towards allowing women to sip in moderation?

Not exactly.

While the new study published in the British Medical Journal adds to others suggesting that having a daily beer or glass of wine when pregnant has no detrimental impact on the developing fetus, it still doesn’t push the evidence tipping point in favor of imbibing, say experts.

The latest research examined the cognitive function of more than 1,600 5-year-olds who were born to Danish mothers who reported drinking during their pregnancy. Kindergartners who were born to mothers who consumed several drinks a week during pregnancy had no higher likelihood of having behavioral problems than those whose mothers abstained from alcohol while they were pregnant. Those born to mothers who binged on more than five drinks at once when they were pregnant, however, did have a significantly higher risk of scoring high on an assessment of cognitive difficulties.

(This was an observational study, so it couldn’t prove that binge drinking led to problems or that light drinking didn’t; it just made statistical associations.)

With results pointing to the dangers of binging, how much alcohol is safe to consume? That’s still a murky question with no clear-cut answers.

Folks from the American College of Obstetricians and Gynecologists responded to the study by tweeting that “the jury may be out for researchers, but ACOG recommends that pregnant women avoid alcohol,” and providing a link to its 2008 position statement against any alcohol consumption during pregnancy.

Too little evidence has accumulated to establish a safe threshold for fetal exposure to alcohol, and scientists still don’t know exactly how many drinks lead to a condition called fetal alcohol syndrome associated with heart defects, poor muscle tone, and mental retardation. They also don’t know how much excess alcohol can trigger a miscarriage or stillbirth, both of which have been linked to alcohol consumption.

The latest study has some limitations in that it looked only at one measure of brain function called executive function, which is responsible for decision-making, impulse control, memory, and organizational abilities. “It’s looking at just one sliver of behavior and only at one point in time,” pointed out Dr. Allison Bryant, a maternal fetal medicine specialist at Massachusetts General Hospital. Thus, it’s impossible to know whether these kids will fare as well academically and socially when they hit their adolescent years and their brains become more fully developed, a point the researchers, themselves, also made in their comments on the study.

Bryant speculated that part of the reason for the lack of knowledge about alcohol’s dangers during pregnancy stems from the fact that so few women drink when pregnant -- or at least drink openly. Alcohol in the United States isn’t like coffee in terms of its popularity as a drink; while many women willingly avoid cocktails, they’re not as eager to give up their jolt of java for nine months.

In Europe where alcohol is consumed regularly with meals, more women may continue drinking lightly during pregnancy, which is why it may be easier for researchers to conduct studies there.

“We tend to have a nuanced conversation with women about caffeine during pregnancy -- about the risk of miscarriage if they consume more than a certain amount,” said Bryant. “At this point, we can’t have that conversation with alcohol. We just tell women they should clearly avoid it altogether.”