Objective: The number of children with polydactyly is increasing. In addition to genetic factors, an influence of maternal behavior or environmental effects during pregnancy is becoming increasingly apparent. However, epidemiological data on these effects are lacking. Methods: This hospital-based, case-control study enrolled 143 infants with polydactyly and 286 controls without genetic diseases to evaluate the association between active and passive maternal smoking during pregnancy and the likelihood of giving birth to a child with polydactyly. Results: Active and passive maternal smoking during pregnancy was associated with an increased risk of giving birth to a child with polydactyly (active smoking: OR=4.74, 95%CI: 1.43-15.65, P=0.011; passive smoking: OR=2.42, 95%CI: 1.32-4.44, P=0.004). After adjusting for confounders, smoking during pregnancy remained significant influence on polydactyly (active smoking: aOR=7.27, 95%CI: 1.72-30.72, P=0.007; passive smoking: aOR=2.41, 95%CI: 1.11-5.23, P=0.026). Conclusion: Active and passive maternal smoking during pregnancy appears to be a risk factor for polydactyly in newborns.
Case-Control Studies ; Child ; Female ; Fingers/abnormalities* ; Humans ; Infant ; Infant, Newborn ; Inhalation Exposure/statistics & numerical data* ; Maternal Exposure/statistics & numerical data* ; Polydactyly/epidemiology* ; Pregnancy ; Pregnancy Complications/etiology* ; Risk Factors ; Smoking/adverse effects* ; Tobacco Smoke Pollution/statistics & numerical data*