Absent toes
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.