The increasing practice of preterm delivery in the fetal interest for conditions such as pre-
eclampsia or intrauterine growth restriction (IUGR) has provided an opportunity to study
placental structure in pregnancies with prenatal evidence of fetal compromise. These data
suggest that the origin of fetal hypoxia in IUGR with absent end-diastolic flow in the umbilical
arteries is due to a failure of oxygen transport from intervillous space to umbilical vein.
Failure of the fetoplacental circulation to extract oxygen from the intervillous space under …