Binge drinking during pregnancy is risky: It can, and routinely does, lead to fetal alcohol syndrome and other troubles that plague a child for life, as the U.S. Surgeon General has warned since the 1980s.
But in recent years, some researchers have suggested a glass of red wine with dinner or other forms of light drinking might be fine for a developing fetus: “[S]mall amounts of alcohol early in pregnancy may be less risky to the mother’s health and the health of their babies than previously believed,” Dr. Howard LeWine wrote in a 2013 Harvard Medical School health blog, while conceding that “not drinking any alcohol during pregnancy is the safest choice.”
New research published Wednesday, however, suggests no alcohol whatsoever is the only safe choice — full stop. University of Washington researchers looked at 84 pairs of twins and siblings who were all exposed to alcohol while they were fetuses and found that “two fetuses exposed to identical levels of alcohol can experience strikingly different levels of neurological damage,” according to a news release.
That means “the only safe amount to drink is none at all,” since some fetuses are more genetically vulnerable to alcohol than others, researchers wrote in the abstract of the study, which was published Wednesday in the journal “Advances in Pediatric Research.”
“The evidence is conclusive,” Susan Astley Hemingway, the lead author and a professor of pediatrics at the University of Washington School of Medicine, said in a statement.
Studying twins revealed something particularly fascinating: Identical twins — whose genes were identical, too — had the same health impacts from prenatal alcohol exposures; but in fraternal twins exposed in utero to the same level of alcohol, one could suffer only mild impacts while the other could have full-blown fetal alcohol syndrome, the researchers said.
Fetal alcohol syndrome disorders can leave children with abnormal facial features, stunted heights, low body weight, smaller heads, bad coordination, hyperactivity, poor memory, learning disabilities and more, according to the Centers for Disease Control and Prevention.
“Alcohol in the mother’s blood passes to the baby through the umbilical cord,” the CDC explains.
Researchers said one in every 14 children the University of Washington diagnoses with fetal alcohol syndrome “had a reported exposure of one drink per day.” And according to the CDC, one in 10 pregnant women in the U.S. says she drank during pregnancy, with a third of those women reporting binge drinking.
Researchers said the biggest health implication the new study revealed is that a baby’s DNA helps determine if he or she will end up with lasting impacts from a mother’s drinking — though researchers don’t yet know why.
“We cannot clinically identify which fetus is more likely to be affected by alcohol exposure and which might be less vulnerable,” Astley Hemingway said. “There is not a test for that.”
To carry out the study, researchers sorted through records on 3,000 people who had been exposed to alcohol in utero over the past quarter century, winnowing that number down to 84 pairs of identical and fraternal twins, and full and half siblings — all of whom had the same levels of fetal alcohol exposure, and all of whom “were raised together and diagnosed at the same age,” researchers said.
The study looked at 9 pairs of identical twins, 39 pairs of fraternal twins, 27 pairs of full siblings and 9 pairs of half-siblings. Researchers discovered that the less related the pair was, the more likely they were to have different impacts from alcohol exposure — with 78 percent of half-siblings experiencing diverging alcohol exposure outcomes, 59 percent of full siblings and 44 percent of fraternal twins, according to researchers.