A new study has found that pregnant women who smoke during pregnancy put their unborn children at significantly greater risk of being born with serious physical abnormalities such as excess, missing, or webbed fingers and toes.
Even a smoking habit of half a pack per day boosts the risk of such birth defects by 29% according to the study that is published in the January issue of Plastic and Reconstructive Surgery.
According to Dr. Benjamin Chang, one of the study’s authors, stated: "Reconstructive surgery to repair limb, toe and finger abnormalities in children represents a large portion of my practice – it is the most common issue I treat. Parents would ask why this happened to their child, but I didn’t have an answer. This study shows that even minimal smoking during pregnancy can significantly increase the risk of having a child with various toe and finger defects."
The researchers analyzed records from over 6.8 million live births in the United States during 2001 and 2002. Digital abnormalities occurred in 5,171 children of mothers who smoked during their pregnancies but who did not suffer from health problems like heart disease, diabetes, or high blood pressure.
The data revealed that children of pregnant women who smoked one to 10 cigarettes per day were 29% more likely to have a child with a toe or finger deformity. This risk increased the more a woman smoked.
Women who smoked 11 to 20 cigarettes daily increased the risk 38%, while women who smoked 21 or more cigarettes per day raised the risk 78%.
These deformities, known as polydactyly, syndactyly and adactyly, are the most common congenital limb abnormalities. Polydactyly is the presence of extra digits on the hands or feet. Syndactyly is having webbed fingers or toes. Adactyly is the absence of fingers or toes.
Syndactyly occurs about once in every 2,000 to 2,500 live births, while polydactyly occurs approximately once in every 600 live births.
Webbed fingers or toes occur twice as often in boys and are more common in Caucasians than African Americans, while Excess digits, are 10 times more common in African Americans and are slightly more common in boys.
Since the causes of these defects are, for the most part, unknown, and most often occur without any family history, researchers have turned to environmental causes, such as smoking, as possible explanations.
Dr. Chang observed that: "The results of this study were interesting. We suspected that smoking was a cause of digital anomalies but didn’t expect the results to be so dramatic. Smoking is so addictive that pregnant women often can’t stop the habit, no matter what the consequences. Our hope is this study will show expectant mothers another danger of lighting up."