Alcohol and pregnancy don’t mix.
That’s the sobering conclusion of a new study that has found no level of alcohol is safe during pregnancy.
Researchers at the University of California, San Diego, determined women who drink during pregnancy put their babies at risk for “fetal alcohol syndrome.” The study, published in the journal Alcoholism: Clinical & Experimental Research, also found alcohol consumption during the latter half of the first trimester is especially harmful and contributes to the syndrome.
The condition strikes about 1 percent of infants, who may suffer physical, behavioral and learning problems, abnormal facial features and small head size.
Lead Researcher Haruna Sawada Feldman and her colleagues tracked 992 California women and their infants between 1978 and 2005, examining patterns of drinking and timing of alcohol exposure to their unborn children.
"Higher [prenatal alcohol exposure] in every pattern we examined was significantly associated with an increased risk for having an infant born with reduced birth length or weight” or other problems, said Feldman. "The most significant associations were seen during the second half of the first trimester.”
Feldman said the findings reinforce previous research that has concluded there is no "safe" level of alcohol consumption during pregnancy.
"Clinicians should continue to follow the recommendations to encourage women who are planning a pregnancy or have the potential to become pregnant to avoid alcohol, and to advise women who become pregnant to stop alcohol consumption," she added. "These new findings can also help clinicians quantify the importance of discontinuing alcohol as early as possible."
The 992 women in the study were enrolled in the California Teratogen Information Service and Clinical Research Program between 1978 and 2005, which provided confidential risk assessments for any potential toxin exposures during pregnancy. Every three months during the remainder of their pregnancies, they were asked about their use of alcohol and other substances, including specific dates of use, drinks per day, number of binge episodes and maximum number of drinks.
Information about their babies' development was collected after birth, and each newborn was then examined by a dysmorphologist, a specialist in structural birth defects, to look for evidence of fetal alcohol syndrome as well as other conditions.
While higher levels of alcohol exposure were strongly linked to a greater risk of infants born smaller and lighter, with small heads and a smooth ridge between the nose and upper lip, the most significant associations were observed during the second half of the first trimester of pregnancy -- defined as 43 to 84 days after conception.
For every one-drink increase in the daily average number of drinks consumed during this stage of pregnancy, there was a 25 percent higher risk for having a smooth ridge between the nose and upper lip; a 22 percent higher chance of having an abnormally thin upper lip; a 12 percent elevated risk of having a smaller-than-normal head; a 16 percent greater risk of reduced birth weight; and an 18 percent higher chance of reduced birth length.
In addition, the likelihood of shorter birth length was associated with drinking in any trimester, the study found.
"There is almost 40 years of research [on fetal alcohol syndrome], but one of the challenges has been determining what are the windows of risk and the patterns in timing and quantity of alcohol use, and this [study] addresses that," said Tom Donaldson, president of the National Organization on Fetal Alcohol Syndrome in Washington, D.C. "This article very clearly demonstrates that risk begins with any use."
Chambers and her colleagues theorized that alcohol exposure in the first six weeks of pregnancy -- when many women don't yet know they're pregnant -- may result in higher miscarriage rates, although the study did not include women who had miscarriages or stillbirths.