Study Finds No Birth Problems after Drinking

September 10, 2013

News Review From Harvard Medical School -- Study Finds No Birth Problems after Drinking

A new study suggests that moderate alcohol use in early pregnancy may not cause early birth or low birth weight for babies. But the authors say it's still unclear whether any level of drinking during pregnancy can be defined as safe. The study included more than 5,600 women. They were interviewed between the 14th and 16th weeks of pregnancy. About 60% said they drank some amount of alcohol during pregnancy. This included only 5% who drank heavily. This was defined as more than 14 drinks a week. About 20% had 1 or 2 drinks a week. About 25% had 3 to 7 drinks and 10% had 8 to 14 drinks per week. More than one-third of all the women had 6 or more drinks in a single session before becoming pregnant. In this study, that was defined as binge drinking. Nearly one-quarter of the same women also binged during pregnancy. The authors compared drinking levels with the status of the women's babies at birth. Drinking any amount before or during pregnancy did not appear to affect the risk of early birth or very small babies. The journal Obstetrics & Gynecology published the study online. HealthDay News wrote about it September 9. 

By Howard LeWine, M.D.
Harvard Medical School

What Is the Doctor's Reaction?

Women should not drink any alcohol during pregnancy. That is the advice of two of the most respected medical societies. They are the American College of Obstetricians and Gynecologists and the United Kingdom's Royal College of Obstetricians and Gynecologists.

Despite this clear advice, up to half of women drink alcohol during pregnancy. So it's important to examine the medical evidence. In fact, the evidence to support absolutely no alcohol use in pregnancy does not exist. And recent studies suggest that pregnant women who have an occasional drink don't harm themselves or their fetus.

This study surveyed women during their first pregnancy. They were asked about alcohol use during the first trimester (the 3 months right after conception). Almost 60% drank some alcohol.

These women did not have a higher risk of harmful events during pregnancy. Their babies were not born early. And the babies' weight and size at birth were normal.

This study did not look at what happened to the children after delivery. But other recent studies have looked at what happens to children of mothers who drank small amounts during pregnancy. In studies of children at ages 5 and 10, those whose mothers had moderate alcohol use during pregnancy did not appear to have any difference in brain development. Moderate drinking means no more than an average of one drink per day and NO binge drinking.

Heavy use of alcohol at any time, but especially during pregnancy, is clearly linked with problems. The one of greatest concern is fetal alcohol syndrome. This causes long-term harmful effects on the unborn child. These effects cannot be reversed.  

Babies with fetal alcohol syndrome may be born early. They are often underweight and do not grow well. They may have certain characteristic facial features, such as a thin upper lip and small eye openings. The little vertical groove between the upper lip and the nose can be flattened. Other physical signs include a small head, short nose and problems with the way the heart or the joints are formed.

Fetal alcohol syndrome is also one of the leading preventable causes of mental retardation in the United States. Young children with this disorder are slower to learn language skills than other kids.

When they reach school age, they often have learning disabilities and difficulty with attention, memory and problem solving. They may be hyperactive and have poor coordination. They are often not as good at making friends and relating to other kids. All of this can make school a really difficult time.

What Changes Can I Make Now?

Since it's not clear how much alcohol it takes to cause problems, the best advice remains the same. Women should avoid alcohol if they are pregnant or might become pregnant. 

However, a woman who happened to drink alcohol early in pregnancy, before she realized she was pregnant, should not feel guilty. She almost surely did no harm to herself or her unborn child.

If you are having trouble stopping alcohol use, notify your doctor, nurse or midwife. You want to get help right away.

What Can I Expect Looking to the Future? 

Not everyone agrees that you should avoid all alcohol if you are trying to get pregnant. Some respected health agencies state that having one alcoholic beverage a couple times per week during pregnancy is okay. But you should never get drunk.

Looking at the evidence, the strict advice to have zero alcohol during pregnancy seems extreme. But will there be consensus about the safety of a glass of wine or a beer once or twice a week? I don't think we will see this any time soon.