Lip or palate: secondhand smoke linked to increase in fetal cleft risk.(Obstetrics)

KISSIMMEE, FLA. -- Women exposed to secondhand smoke have a 1.3 times risk of delivering a child with cleft palate and a 1.2 times risk for cleft lip, according to preliminary data from the National Birth Defects Prevention Study, Dr. Sonja Rasmussen reported at a meeting sponsored by the American College of Medical Genetics.

"This is the first study that has shown women who are exposed to tobacco have an increased risk of borderline significance of cleft lip or palate," said Dr. Rasmussen of the Centers for Disease Control and Prevention, Atlanta. "This is important because even a small increased risk with an exposure as common as environmental tobacco smoke can have a significant public health effect. If the numbers are right, then you have the power to eliminate these problems."

The National Birth Defects Prevention Study is a large case-control study of infants born with 40 different major congenital anomalies. It includes 10 sites, and enrolled participants through a surveillance system. Researchers interview mothers of study infants and obtain buccal cells from the infants and parents for DNA analysis. Since its inception in 1997, 18,824 infants with defects have been enrolled as have 6,696 controls. Investigators have completed 16,000 interviews.

Investigators decided to test the old hypothesis about smoking and clefts, using data from infants born between Oct. 1, 1997, and Dec. 31, 2000. This portion of the study ...