New Data Links Alcohol to Type of Birth Defect

Pregnant women who have one or two drinks a day do not put their babies at greater risk for most birth defects, but even small amounts of alcohol may be linked to one malformation, government doctors said Friday.

National Institute of Child Health and Development scientists analyzed the drinking habits and pregnancy outcomes of 32,870 women and found that women who had two drinks or less a day had the same risk of birth defects overall as women who did not drink.

When the researchers looked at defects in specific organ systems, however, they found the rate of genital or urinary systems defects in newborns increased significantly with a mother’s increasing alcohol consumption.

Direct Relationship

“We did find a direct relationship between the amount of drinking--even in light amounts--and an increased risk of urogenital malformations,” Dr. James Mills said. “This is something that will have to be confirmed, perhaps by another study.”

Mills also warned that moderate drinking as defined in the study did not include people who may not drink at all during the week but have seven or eight drinks on a Friday or Saturday night.

“If you’re pregnant, you must avoid that sort of behavior entirely,” he said. “It may be a binge drinker who is at greatest risk.”

Mills called the government’s findings, reported in the journal Pediatrics, encouraging because they showed that alcohol, at levels usually consumed during pregnancy, does not increase the risk of birth defects in general.

‘Partially Academic’

“But that’s partially academic, because my recommendation to women would still be, ‘Don’t drink when you’re pregnant,’ ” he said. “We still clearly do not know enough about this.”

The adverse effects of heavy or binge drinking during pregnancy are well known as fetal alcohol syndrome, which includes spontaneous abortions, still births, low birth weights and a higher risk of physical and mental defects.

The effects of moderate or light drinking are less clear, however.