The Centers for Disease Control and Prevention reported that as many as 15 percent of pregnant women say they consumed alcohol while they were pregnant and 6 percent reported binge drinking.

But that's not the whole story. Two studies conducted independently and published in the journal, Alcohol: Clinical and Experimental Research, show that when and how mothers drink alcohol while they're carrying a baby can make a difference in the child's health.

In one study researchers studied 281 mother-infant pairs in New Mexico and analyzed the birthing parent's drinking behaviors in the weeks that were closest to conception (before pregnancy was apparent), as well as throughout the pregnancy. Using statistical analysis, the University of New Mexico-led team were able to examine the connection between drinking patterns, fetal growth and gestational age (the period of time between conception and birth) at delivery.

Even infrequent, but binge-type drinking, contributed to the brain damage and growth problems related to Fetal Alcohol Syndrome Disorders.

Eighty-four percent of birthing parents in this group said they engaged in at least one binge drinking episode during a month around their last menstrual period, when they averaged 14 drinks a week. During their second trimester, they had approximately one drink a week; and it reduced to less than a drink a month in the third trimester. Analysis of the data showed:

  • The average amount of drinking per day during the weeks closest to conception and throughout pregnancy was related to having an infant born at an earlier gestational age.
  • The number of drinks consumed were inversely related to a reduced birth length — as drinking went up, birth length went down.
  • The total amount of alcohol consumed by the mother during pregnancy was also inversely related to a modest decline in her child's cognitive function.
  • The amount consumed per occasion had the greatest effect on children whose mothers drank at least twice a week.

The New Mexico study underscores the impact of Prenatal Alcohol Exposure (PAE) very early in pregnancy and the impact of as little as one drink a week or less later in pregnancy on preterm delivery.

The second study examined data from 2,227 pregnant parents living in four U.S. cities. The Wayne State University researchers used statistical analysis to look at the relationship between drinking frequency, as well as the amount consumed per drinking occasion, and its relationship with measures of cognitive function in childhood, adolescence and young adulthood.

The study showed that even infrequent, but binge-type drinking, was a key element contributing to Fetal Alcohol Syndrome Disorders (FASD). FASD are characterized by brain damage and growth problems. Issues related to FASD vary from child to child, but can include:

  • Trouble with learning, memory and paying attention.
  • Difficulty communicating, understanding language, decoding meaning.
  • Hyperactivity, impulsivity and other behavioral problems.

The CDC offers this advice on drinking during pregnancy: “If you used any amount of alcohol while you were pregnant, speak with your child health care provider as soon as possible and share your concerns. Make sure you get regular prenatal checkups.”