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Moderate drinking during pregnancy may not harm baby's neurodevelopment

Moderate drinking during pregnancy may not have an effect on the brain development of the baby, according to a new study.

Researchers have found that on average, children of mothers who drank between one and seven glasses of alcohol a week during pregnancy did not have balance problems by the time they reached the age of 10. Some children even appeared to have better static balance measurements (balancing without moving) compared to the offspring of mothers who did not drink.

The researchers tracked 6,915 10-year-olds who were born between 1991 and 1992 in addition to their parents, all of whom were part of the Avon Longitudinal Study of Parents and Children (ALSPAC).

Balance is determined by brain development in the womb, which could give researchers insight into whether drinking damaged the fetus' brain.

The mothers were asked about their alcohol consumption levels at 18 weeks of pregnancy and 47 months after pregnancy. Seventy percent of mothers abstained from drinking while pregnant. One in four drank between one and two drinks (defined by researchers as low consumption) and three to seven glasses (moderate consumption) a week.

About 4.5 percent of moms drank seven or more glasses (high consumption) a week. One out of seven of those women were binge drinkers, meaning they drank four or more drinks at each sitting. Binge drinkers tended to be poorer and younger. The mothers who drank more but were not binge drinkers tended to be older and more affluent.

Four years after pregnancy, more than 28 percent of moms were not drinking. A little more than half were drinking at least three glasses a week.

Dads were also asked how much they were drinking while their partner was 18 weeks pregnant. Over half consumed one or more drinks a week, and 20 percent said they drank one or more glasses a day.

At age 10, the children were given a 20-minute balance assessment. The test involved dynamic balance (judged by time it took to cross a 2-meter long balance beam walking heel to toe), static balance eyes open (walking heel to toe on a balance beam with the eyes open and standing on one leg with the eyes open for 20 seconds each) and static balance eyes closed (same test as static balance eyes open but with the eyes shut). Children with good balance had the top 25 percent crossing times for the dynamic balance test, completed the entire static balance test with their eyes open and were in the top 25 percent of times for the static balance test eyes closed.

It was shown that mothers who drank low to moderate levels during and after pregnancy, as well as fathers who had higher levels of drinking during the first three moths, tended to have children who had better balance, especially static balance.

To see if drinking alcohol actually boosted balance performance, researchers conducted blood tests looking at 4,335 mothers who were determined to have a genetic predisposition to low levels of alcohol consumption. If drinking did help improve balance, mothers with the low alcohol consumption gene would have had children with worse balance.

However, mothers with the genetic predisposition had children with about the same balance as mothers without the gene, meaning alcohol did not aid in developing balance. The study still did show that alcohol did not seem to affect balance in any way.

Dr. James Nicholls, research manager at Alcohol Research UK, told The Independent that the study made an "important contribution."

"Although [balance] is only one measure of neurodevelopment, it should not be disregarded," he said. "The debate on advice to women in pregnancy is an important one, and many people will argue that the 'precautionary principle' of advising no alcohol at all should hold. However, while advice needs to be clear, we should also take note of evidence which points to the conclusion that small amounts of alcohol are not a significant risk."

This isn't a sign that all women should be okay to drink while pregnant. Social advantage may have played a role in this study, since more well-off and educated mothers were more likely to drink moderately.

The Centers for Disease Control and Prevention cites fetal alcohol syndrome, birth defects, and low birth weight as side effects from drinking during pregnancy. These are some of the most preventable birth defects and developmental disabilities.

On average in the U.S., about 1 in 13 pregnant women drink, according to a July 2012 report in the Morbidity and Mortality Weekly Report.

Study: Light drinking during pregnancy not harmful to child

Dr. Robert Sokol, professor at Wayne State University School of Medicine, pointed out to CNN that other studies have shown that alcohol is not associated with some developmental defects. A study in BJOG: An International Journal of Obstetrics and Gynaecology in April showed that low levels of drinking (one to two glasses a week) may not have cause any harm to the fetus. Still, in all the studies, there may be other factors that could have prevented problems despite the fact the mothers were drinking, including the fact that some people are more affected by drinking than others.

"We don't know a safe level, so the smartest advice is what the ACOG (American Congress of Obstetricians and Gynecologists) says: Don't drink," Sokol said. "If I were pregnant, I wouldn't drink."

The study was published in BMJ on June 17.