Birth defects or congenital malformations are inborn structural abnormalities of organs or body parts. The frequency is by definition measured as prevalence at the time of birth and occurs in 3.5% of all live births. Since the thalidomide disaster in the 1950s and 1960s there has been a focus pertaining to limb defects among newborns. Nearly 70% of all birth defects have no known risk factors. The prevalence of congenital limb defects is 0.5–1 per 1000 births. Several studies reported that maternal smoking during pregnancy might increase the risk of limb defects. Limb reduction defects in general are caused by developmental defects causing vascular disruption or exposure in utero to teratogens. There are reports of limb disruption defects associated with chorionic villus sampling, amniotic band syndrome, and mesoprostol exposure in first trimestra.