Women who smoke during pregnancy run a higher risk of having a baby with a cleft palate or lip, and babies born to smokers are twice as likely to be born with the conditions as opposed to babies of nonsmokers, according to a new study from the March of Dimes California Research Division.

A unique feature of the study is that it did not rely on women's self-reported smoking habits during pregnancy. Instead, researchers used the method of measuring the levels of cotinine, a metabolite of nicotine, in the blood from about 500 pregnant women.

"This research is the first time we've been able to measure something -- in this case cotinine -- and determine the risk of smoking during pregnancy for oral-facial birth defects," stated Gary M. Shaw, Ph.D., research director and senior epidemiologist of the March of Dimes California Research Division, in a press release.

"The message to women is simple and clear: Don't smoke during pregnancy or even if you are considering becoming pregnant," said Dr. Jennifer L. Howse, president of the March of Dimes.

The study -- "Mid-Pregnancy Cotinine and Risks of Orofacial Clefts and Neural Tube Defects" -- will soon be published in the Journal of Pediatrics.

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