Alcohol Consumption Most Dangerous in Early Pregnancy

Drinking and pregnancy don’t mix, but when are babies most vulnerable to the effects of alcohol?

The end of the first trimester appears to be the period when alcohol can wreak the most havoc on fetal development, causing physical deformities as well as behavioral and cognitive symptoms, according to research in the journal Alcoholism: Clinical & Experimental Research.

According to the March of Dimes, about 1 in 12 women admit to drinking during pregnancy, and 1 in 30 say they binge-drink, or consume five or more drinks at one sitting. Exposure to alcohol in utero leads to fetal alcohol spectrum disorders in about 40,000 newborns every year in the U.S. While adults can break down alcohol relatively safely, still-developing fetuses tend to keep more alcohol in their blood, which can hinder the development of brain and body.

Deformities associated with fetal alcohol syndrome include small head, small upper jaw, smooth and thin upper lip and small, narrow eyes.

When women consumed alcohol between the seventh and 12th weeks of their pregnancies, the risk of problems with their newborn's lips increased by 25 percent per drink, the chance of a shorter length of the baby climbed 18 percent, the possibility of reduced birth weight rose 16 percent, and the chance of having a smaller head size went up 12 percent, according to the study.

"These findings show that drinking alcohol between week seven and 12 of pregnancy are clearly associated with a risk for (fetal alcohol syndrome) facial features, as well as a decrease in birth weight and length," said Christina Chambers, a professor of pediatrics at UC San Diego and CTIS program director.

Chambers said the results do not mean it is safe to drink in the first seven weeks of pregnancy, since the study only looked at live births and does not include miscarriages or stillbirths caused by alcohol exposure.

"If anything, this further supports the idea that there is no designated safe period for drinking alcohol in pregnancy, and that discontinuing alcohol consumption as soon as possible, and, ideally, prior to pregnancy is the best approach to preventing FAS," Chambers said.

According to the U.S. National Library of Medicine, children with FAS could face brain developmental problems that affect coordination, movement, thinking, speech and social skills. There is also a risk of have heart defects.