TUESDAY, Jan. 17 (HealthDay News) – It is known that drinking during pregnancy causes babies are vulnerable to a variety of abnormalities known as fetal alcohol syndrome. Now, a recent study suggests that the second half of the first trimester is a critical time for the development of some of the strongest physical characteristics of the syndrome.
The study’s authors said their research also shows that no amount of alcohol is safe during pregnancy, since the amount of drink that produced these characteristics in infants varied from woman to woman.
“The fact that we found a safe threshold is important,” stressed study author Christina Chambers, associate professor of pediatrics and family and preventive medicine at the University of California at San Diego. “Not all the children of women who drink even much have all the features, but there are certain factors of susceptibility to know.”
The study appears online Jan. 16 in advance of its publication in the April print issue of the journal Alcoholism: Clinical & Experimental Research. The authors say it is the first to examine the impact of the amount, frequency and timing of alcohol exposure on the condition.
It is believed that fetal alcohol syndrome affects about 1 percent of the U.S. population. It can result in physical, behavioral and learning. People who suffer from the syndrome may have abnormal facial features, such as a flat groove between the nose and upper lip, small head, eyes unusually close and below average height.
The 992 women in the study were enrolled in the Program Information Service and Clinical Research Reproductive California between 1978 and 2005. It provides confidential assessments of risk for potential exposure to toxins during pregnancy. Every three months during the remainder of the pregnancy, they were asked about their use of alcohol and other substances, including the specific dates of use, drinks per day, the number of binges and the maximum number of drinks.
Information on the development of babies after birth was collected, and each infant was examined by a dismorfólogo, a specialist in structural birth defects, for evidence of fetal alcohol syndrome among other conditions.
While higher levels of alcohol exposure is strongly associated with an increased risk of smaller babies and weight, with small heads and a flat groove between the nose and upper lip, the most significant associations were observed during the second half of first trimester of pregnancy, defined as 43 to 84 days after conception.
For every increase of one drink in the average daily number of drinks consumed during that stage of pregnancy, there was a 25 percent increase in the risk of having a flat groove between the nose and upper lip, an increase of 22 percent in the odds of having an abnormally thin upper lip, a 12 percent increase in the risk of having a smaller head than normal, a 16 percent increased risk of low birth weight, and 18 percent more likely a small stature at birth.
And the likelihood of a lower height at birth were associated with drinking in any trimester, the study found.
“There are almost 40 years of research [on fetal alcohol syndrome], but one of the difficulties has been to determine which are the windows of risk and patterns due to the timing and the amount of alcohol, and this [study] it addresses” said Tom Donaldson, chairman of the National Organization on Fetal Alcohol Syndrome (National Organization on Fetal Alcohol Syndrome) in Washington, DC “This article clearly demonstrates that the risk starts from any use.”
Chambers and colleagues theorized that exposure to alcohol in the first six weeks of pregnancy, when many women still do not know they are pregnant, could result in higher rates of spontaneous abortion, although the study did not include women who had suffered spontaneous abortions or stillbirths.