Washington: Drinking alcohol during pregnancy can cause a spectrum of abnormalities referred to as Fetal Alcohol Spectrum Disorders in the offspring, experts say.
Physical features of the more serious Fetal Alcohol Syndrome (FAS) include smooth philtrum, thin vermillion border, short palpebral fissures, microcephaly, and growth deficiencies in weight and height.
A new study has specified how specific quantities of alcohol exposure, patterns of drinking, and timing of exposure can have an impact on each of these features.
Numerous specific associations were found, the most significant ones during the second half of the first trimester of pregnancy.
Haruna Sawada Feldman, a post-doctoral student in the department of pediatrics under the mentorship of professor Christina Chambers at the University of California, San Diego, and her colleagues used data gathered on 992 women and their singleton infants in California between 1978 and 2005, examining patterns of drinking and timing of alcohol exposure in relation to selected FAS features.
Structural features were assessed by a dysmorphologist who performed a blinded physical examination of all infants. Patterns of drinking were evaluated by drinks per day, number of binge episodes, and maximum number of drinks.
Timing of exposure was evaluated zero to six weeks post-conception, six to 12 weeks post-conception, and during the first, second, and third trimesters.
“Higher prenatal alcohol exposure (PAE) in every pattern we examined was significantly associated with an increased risk for having an infant born with reduced birth length or weight or having a smooth philtrum or thin vermillion border or microcephaly,” said Feldman.
“The most significant associations were seen during the second half of the first trimester; for every one drink increase in the average number of drinks consumed daily, there was a 25 percent increased risk for smooth philtrum, a 22 percent increased risk for thin vermillion border, a 12 percent increased risk for microcephaly, a 16 percent increased risk for reduced birth weight, and an 18 percent increased risk for reduced birth length,” the researcher stated.
Feldman added that the lack of associations found during first-half of the first trimester between alcohol and outcomes should not be interpreted to mean that alcohol consumption during this time period is somehow safe.
“Due to the study design, we were only able to include women who gave birth to live infants,” she said.
“Therefore, we did not include women who may have had miscarriages or stillbirths. It is important to know that alcohol-exposed infants who would have exhibited alcohol-related minor malformations might also be more likely to be lost to miscarriage following exposure during the first six-week window,” she added.
Both Feldman and Philip A. May, a research professor in the Gillings School of Global Public Health at The University of North Carolina, believe these findings reinforce the warning that there is no “safe” level of alcohol consumption during pregnancy.
The results will be published in the April 2012 issue of Alcoholism: Clinical and Experimental Research and are currently available at Early View.