Vast majority of congenital malformations are related to aneuploidy or abnormal embryonic development in the first 8 weeks following conception.
Incidence of congenital deformities in newborns is approximately 2%, and 10% of these deformities involve the upper extremity.
Among humans, about five percent of live-born offspring have a genetic disorder, and of these, about 20% are due to newly arisen germline mutations.
Risk of preterm delivery and low birth infants is increased 2-3 fold among fetuses in the lowest quartile of first trimester growth.
The majority of congenital anomalies occur during the 4-week embryologic period of rapid limb development.
Accounts for 22% of all infant deaths.
The risk of major structural birth defects among live births is approximately 3%.
Major structural birth defects are associated with inherited or de novo genetic rearrangements and mutations as well as maternal factors such as advanced age, certain clinical diseases, and exposure to catch agenic factors.
Approximately one in 2000 prenatal cases analyzed with conventional karyotyping has a de novo balanced reciprocal translocation that carries a 6.1% risk of congenital malformation.
Ultrasound in utero between 18 and 20 weeks of gestation allows detection of major malformations and is routine.
90% of infants with congenital abnormalities are born to women without predisposing risk factors.