pregnancy increase the likelihood that their babies will be born with

oral clefts.

The researchers found that women who consumed an average of five or more

drinks per sitting were more than twice as likely than non-drinkers to

have an infant with either of the two major infant oral clefts: cleft

lip with or without cleft palate, or cleft palate alone. Women who drank

at this level on three or more occasions during the first trimester were

three times as likely to have infants born with oral clefts.

“These findings reinforce the fact that women should not drink alcohol

during pregnancy,” said Lisa A. DeRoo, Ph.D., an epidemiologist at NIEHS

and author on the study. “Prenatal exposure to alcohol, especially

excessive amounts at one time, can adversely affect the fetus and may

increase the risk of infant clefts.” The causes of clefts are largely

unknown, but both genetic predisposition and environmental factors are

believed to play a role in their development. The paper appears online

today as an advance access publication in the /American Journal of

Epidemiology/.

The population-based study was conducted in Norway, which has one of the

highest rates of oral clefts in Europe. The investigators contacted all

families of newborn infants born with clefts between 1996 and 2002. The

study included 573 mothers who had babies born with cleft lip with or

without cleft palate and cleft palate only; as well as 763 mothers

randomly selected from all live births in Norway. The average age of the

mostly married mothers was 29 years.

Mothers completed a self-administered mailed questionnaire focused

heavily on the mother’s lifestyle and environmental exposures during her

first three months of pregnancy when a baby’s facial development takes

place.

The researchers found increased risks of orofacial clefts among infants

whose mothers reported binge-level drinking of an average of five or

more drinks per occasion during the first-trimester compared to

non-drinkers. Risk was further increased among women who drank at this

level most frequently.

Both animal and human data suggest that it is the dose of alcohol

consumed at one time during pregnancy rather than the frequency or total

amount over time that matters most. “The greater the blood alcohol

concentration, the longer the fetus is exposed. A single binge during a

critical period of an infant’s development can be harmful,” said DeRoo.

“Fortunately, heavy maternal drinking is uncommon in many populations,

but the fact that it is happening at all tells us we need to do a better

job of letting mothers know about the effects that alcohol can have on

their baby’s development,” said Allen J. Wilcox, M.D., Ph.D., NIEHS

researcher and co-author on the paper. In Norway, a separate study found

that 25 percent of Norwegian women reported at least one binge drinking

episode early during pregnancy.

Alcohol is a recognized teratogen, or an environmental agent that can

cause malformations of an embryo or fetus. One of the most severe

outcomes of heavy maternal drinking is fetal alcohol syndrome, a

lifelong condition that causes physical and mental disabilities,

including craniofacial malformations. There has been little research to

determine if alcohol consumption is related to oral cleft risk.

The research was supported by the Intramural Research Program of the

NIH, NIEHS. Researchers at the University of Bergen, the University of

Oslo and the Medical Birth Registry of Norway also contributed to this

study.

The primary mission of the National Institute of Environmental Health

Sciences (NIEHS), one of 27 Institutes and Centers at the National

Institutes of Health, is to reduce the burden of human illness and

disability by understanding how the environment influences the

development and progression of human disease.

The National Institutes of Health (NIH) - / The Nation’s Medical

Research Agency/ - includes 27 Institutes and Centers and is a component

of the U.S. Department of Health and Human Services. It is the primary

federal agency for conducting and supporting basic, clinical and

translational medical research, and it investigates the causes,

treatments, and cures for both common and rare diseases.

*Reference:* DeRoo LA, Wilcox AJ, Drevon CA, Lie RT. First-trimester

maternal alcohol consumption and the risk of infant oral clefts in

Norway: a population-based case-control study. /American Journal of

Epidemiology /Advance Access published July 30, 2008, doi:

10.1093/aje/kwn186.

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