Mothers’ Smoking Doubles Risk of Cleft Palates

Babies born to mothers who smoke have double the risk of developing cleft lips and palates, according to a new study from the California Birth Defects Monitoring Program.

The risk is even higher for babies who carry a particular variant of a gene called TGFa, about one in every seven infants. Their risk is increased eightfold above the normal risk if their mothers smoke, according to a report in today’s issue of the American Journal of Human Genetics.

The study has important implications for the one in every four California women who smoke during pregnancy, according to state health Director Kim Belshe.

“This is the strongest link to date between smoking and a structural birth defect,” Belshe said. “Cutting out cigarettes could save 2,000 babies nationwide each year from the physical and emotional scars of oral clefts.”

Every year, about 7,000 U.S. babies are born with oral clefts, 1,000 of them in California. A cleft is an opening in the upper lip, the roof of the mouth (palate) or both. Children born with oral clefts require significant medical care, often four surgeries by age 2. The average lifetime costs for medical care and related expenses are estimated at about $100,000 per child.

Epidemiologist Gary M. Shaw and his colleagues at the program interviewed almost 1,500 women regarding their smoking habits during the month before conception through the third month of pregnancy. The study is the first to look at the influence of both smoking and genetics on this birth defect.

The team found that women who smoked 20 cigarettes per day or more were more than twice as likely to have a baby with a cleft lip or cleft palate, while those who smoked fewer than 20 cigarettes per day were 1.5 times as likely as women who don’t smoke. A father’s smoking increased the risk for oral clefts only if the mother smoked also, the researchers found.

The researchers also performed DNA typing to determine whether the infants had one particular form of TGFa, formally known as transforming growth factor-alpha--which plays a role in the development of the palate and mouth. They do not yet know how smoking interacts with this gene to cause the increased risk of oral clefts.

The team also found that the mother’s age, ethnicity or education did not significantly alter the effects of smoking.

* FOLIC ACID IN FOOD: Folic acid will be put into most grain products to cut birth defect risks. A10