Smoking during pregnancy might raise the risk of having a baby with extra, missing or webbed fingers and toes. Researchers from the University of Pennsylvania in Philadelphia used the information from a national database on U.S. births and found that babies born to women who smoked during pregnancy were 31 percent more likely to have such birth anomalies as babies of non-smokers. And the more a woman smoked, the greater was the risk. It's estimated that about 1 in 600 infants are born with an extra finger or toe - an anomaly known as polydactyly. Webbed fingers or toes, called syndactyly, are less common, occurring in one in every 2,000 to 2,500 births. While it's well known that prenatal smoking can have serious consequences such as miscarriage, premature delivery and low birth weight, studies have yielded conflicting results on whether smoking can cause birth defects of the fingers and toes. In the current study, the researchers analysed information from a national database covering nearly all live births in the U.S. between 2001 and 2002. Of more than 8.0 million births, maternal smoking information was available for 6.8 million. It was found that a total of 6,522 infants had polydactyly, syndactyly or adactyly (the absence of fingers or toes). Of these infants, 1,121 had other abnormalities, and were excluded from the analysis. Overall, 5,171 infants were included in the final analysis. The risk was not only greater among babies born to smokers, but it rose as the number of cigarettes a mother smoked during pregnancy increased. Babies whose mothers smoked at least 21 cigarettes a day were most at risk, being 78 percent more likely than infants of non-smokers to have a finger or toe anomaly. But even relatively light smoking - 10 or fewer cigarettes a day - boosted the risk by 29 percent. The extent to which smoking raised the odds of these birth anomalies was surprising. Hopefully this study will show expectant mothers another danger of smoking.
Plastic and Reconstructive Surgery,
January 2006