Background:The number of children with polydactyly seen in our clinic is increasing. In addition to genetic factors, an influence of 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 patients with polydactyly and 286 control patients with no genetic diseases, to evaluate the association between maternal exposure to a textile factory environment during pregnancy and the likelihood of giving birth to a child with polydactyly. Results:Maternal exposure to a textile factory environment during pregnancy was associated with an increased risk of giving birth to a child with polydactyly (exposure to textile factory environment: unadjusted odds ratio (OR) = 3.31, 95% confidence interval (CI) = 1.75-6.27,p = .0002; work seniority of exposed occupation: unadjusted OR 1.28, 95% CI = 1.13-1.47,p = .0002). Covariate screening indicated that certain risk factors (family monthly incomeper capita, mother's emotional state during pregnancy, colporrhagia, passive smoking, smoking, and history of consanguineous marriage) were potential confounding factors. After adjusting for these variables, the OR of exposure to a textile factory environment remained significant (exposure to textile factory environment: adjusted OR = 3.08, 95% CI = 1.32-7.19,p = .0094; work seniority of exposed occupation: adjusted OR = 1.58, 95% CI = 1.20-2.08,p = .0010). The risk of polydactyly increased with the number of years of employment. Conclusions:Maternal exposure to a textile factory environment appears to be a risk factor for polydactyly in newborns.