Study: 15 percent of pregnant women drink alcohol

Most have less than one drink a week, but risky drinking seen in some

Ongoing study now looking at how mental health issues might play a part

ANN ARBOR, MI – Despite widespread warnings about the potential risk of drinking alcohol during pregnancy, fifteen percent of pregnant women in a newly published study said they had drunk alcohol at least once during their pregnancies.

And although most of those women reported on an anonymous survey that they’d had less than one drink a week, some acknowledged drinking more than that on a regular basis, or said they’d had at least one binge of five or more drinks at once.

The study, published in the Jan. 2003 issue of the journal Alcoholism: Clinical and Experimental Research by a team from the University of Michigan Health System, also found that women who smoke during pregnancy were more likely to drink alcohol too – as were women in earlier stages of pregnancy. And only about half of the women recalled being asked about their drinking by their obstetric provider.

In all, the authors say, the results suggest that doctors and other health care providers should assess all women’s drinking behavior during prenatal visits, and counsel certain women more intensely about drinking alcohol during pregnancy.

“The good news is, most pregnant women aren’t drinking, and those who do drink aren’t drinking much,” says lead author Heather Flynn, Ph.D., an assistant research scientist at the University of Michigan Addiction Research Center and a clinical associate in the U-M Medical School’s Department of Psychiatry. “But there’s a subgroup that’s at high risk, and we need to do more to understand and reach them.”

Flynn and her colleagues are already tackling that next step, with a study that’s looking at the psychological and psychosocial factors that influence a woman’s tendency to drink alcohol during pregnancy. Through this research, funded by the National Institute on Alcohol Abuse and Alcoholism, they’re examining the interplay of drinking behavior with depression, stress, domestic violence and other issues.

The specific dose-related effects of alcohol exposure in the womb on a child’s mental and physical health have not been well documented. Still, most medical authorities advise that pregnant women refrain from drinking alcohol, though a few suggest that an occasional drink may pose an acceptably low risk to the fetus.

The results reported in the new paper document the incidence of alcohol use among a large, diverse and general population of women, as well as demonstrating the feasibility of surveying such a group for the purposes of screening for alcohol use.

The study represents the largest and broadest assessment of drinking in pregnancy since 1995; other studies have mainly focused on at-risk populations or ethnic groups with a high risk of fetal alcohol syndrome, a rare but devastating cause of birth defects and mental retardation in children that has been shown to be brought on by heavy drinking during a woman’s pregnancy.

Flynn and her colleagues surveyed 1,131 pregnant women, ranging in age from 18 to 46 years, while they were waiting for prenatal appointments at eight obstetrics clinics in southeast Michigan. The women were between 3 and 41 weeks pregnant, and the racial makeup of the group was similar to that of the regional population. The respondents were assured that their answers would be anonymous and would not affect their care. Only 8 percent of women approached declined to complete the survey.

The women were given written surveys that asked about a range of health and lifestyle issues, including exercise and tobacco use, so that alcohol-related questions blended in. The surveys included both direct questions about drinking during pregnancy, and indirect questions about drinking habits in the past year, using a validated survey instrument called TWEAK. A TWEAK score of two or higher indicates a potential for risky drinking behavior. All but 15 women answered the alcohol questions, leaving 1,116 surveys to be analyzed.

The researchers divided up the women who reported any alcohol use during pregnancy into low- and high-risk groups. Eighty-six percent of the women fell into the low-risk group, consuming less than one drink per week and reporting no binges of five drinks or more at a time. The remainder were those who drank one drink or more per week, or who had one or more drinking binges during pregnancy. They account for 3 percent of the entire survey group.

Binge drinking was uncommon, but measurable: Seven percent of the women using alcohol reported one or more binge drinking episodes during their pregnancy.

Thirteen percent of all women – whether or not they used alcohol during pregnancy – scored two or higher on the TWEAK scale of drinking behavior. But the proportion was higher among alcohol-using women, at 19 percent of the low-risk group and 29 percent of the high-risk group.

There were no significant differences in drinking behavior associated with the women’s marital status, race or education. But age, smoking and earlier stages of pregnancy did correlate with a higher incidence of alcohol use. Women in the high-risk group smoked twice as many cigarettes per day than women in the low-risk group, and three times as many cigarettes per day as women who didn’t drink. Women in the earlier stages of pregnancy were more likely to drink.

Among the women who reported any drinking, just over 54 percent said their health care provider had talked with them about drinking while pregnant. This reflects known trends among clinicians, Flynn says – many feel they don’t have the time or training to address drinking with their patients. But the results of the survey, she says, may help providers see that their staff can screen their patients for alcohol use, revealing which patients should receive further follow-up.

“We may be able to identify, through quick screening, the women who may be at highest risk for harmful outcomes for themselves and their infants, and stop those potentially risky behaviors,” says Flynn. “But first, we need to better understand the relationships between drinking, tobacco use, and other mental health issues in pregnancy.”

In addition to Flynn, the research team includes U-M associate professor of psychiatry Sheila Marcus, M.D.; Kristen Barry, Ph.D., senior associate research scientist at UMARC; and Frederic Blow, Ph.D., associate professor of psychiatry and senior associate research scientist at UMARC. The survey was carried out by U-M psychology students, with cooperation from the U-M Department of Obstetrics and Gynecology, chaired by Timothy R. B. Johnson, M.D.