Cordocentesis in the diagnosis of intrauterine starvation.

Glycine and valine were measured in umbilical venous blood obtained by cordocentesis from 28 small-for-gestational-age fetuses. The values were compared with those from 62 appropriate-for-gestational-age fetuses. The ratio of glycine to valine was higher in the small-for-gestational-age fetuses and correlated significantly with the degree of fetal hypoxemia. These findings indicate that placental insufficiency is associated with a biochemical disturbance in the fetus that is similar to that observed in children with protein deprivation and kwashiorkor syndrome.