One in 10 pregnant women in the U.S. admit to drinking alcohol at least every now and then, and a third of the drinkers admit to binge drinking, federal researchers said Thursday.
They're putting their children at risk of fetal alcohol syndrome, which affects 2 to 5 percent of first-graders, the Centers for Disease Control and Prevention says.
There's no known safe level of alcohol use during pregnancy. Alcohol passes from mother to fetus and experts advise women who are pregnant or who may become pregnant to just keep away from alcohol.
"All types of alcohol should be avoided, including red or white wine, beer, and liquor," said Cheryl Tan, an epidemiologist in CDC's National Center on Birth Defects and Developmental Disabilities.
"Excessive alcohol use is a risk factor for a wide range of health and social problems including liver cirrhosis, certain cancers, depression, motor vehicle crashes, and violence," Tan and colleagues wrote in the agency's weekly report on death and disease.
"Alcohol use during pregnancy can lead to fetal alcohol spectrum disorders (FASD) and other adverse birth outcomes. Community studies estimate that as many as 2 percent to 5 percent of first grade students in the United States might have an FASD, which include physical, behavioral, or learning impairments."
The researchers looked at a survey of more than 200,000 women taken from 2011 to 2013 for their report. It included more than 8,000 who were pregnant at the time.
Older mothers and college graduates were more likely to report drinking. Ten percent of all the pregnant women said they'd had a drink in the past 30 days, and 3 percent said they'd had four or more in a row, which is classified as binge drinking.
Nearly 19 percent of the pregnant women aged 35 to 44 admitted to having at least one drink while pregnant. Thirteen percent of college graduates and 13 percent of unmarried women also said they'd had a drink.
In comparison, just over half of all women aged 18 to 44 in the U.S. report having an alcoholic drink in the past 30 days and 18 percent report binge drinking.
But the pregnant women who admitted the binge drinking said they did it more often — 4.6 times over the past 30 days, compared to three times over the past month for all women in the same age group.
"One possible explanation for this might be that women who binge drink during pregnancy are more likely to be alcohol-dependent than the average female binge drinker, and therefore binge drink more frequently," the researchers wrote.
"We know that alcohol use during pregnancy can cause birth defects and developmental disabilities in babies, as well as an increased risk of other pregnancy problems, such as miscarriage, stillbirth, and prematurity," said Coleen Boyle, director of CDC's National Center on Birth Defects and Developmental Disabilities.
"This is an important reminder that women should not drink any alcohol while pregnant. It's just not worth the risk."
The report may underestimate how many women drink while pregnant. The researchers noted women may not want to admit to behavior they know is harmful, and women often do not realize they are pregnant for the first four weeks or sometimes longer.