Fetal malformations and abnormalities.

The prevention of fetal malformations and abnormalities has long been the hope 
of obstetricians, paediatricians, and geneticists, but since the cause of most 
human malformations and of spontaneous gene and chromosome mutations is unknown, 
this must remain a dream for the present. However, with the 
introduction of mid-trimester amniocentesis it is now possible to detect some 
abnormalities early enough for selective abortion of abnormal fetuses, though this 
should be considered a temporary expedient only. The abnormalities which are 
amenable to this approach are the chromosome aberrations such as Down's 
syndrome, the neural-tube malformations including spina bifida cystica, and some recessively 
inherited and X-linked metabolic disorders. 