ObjectiveTo identify placental histopathology associated with absent and reversed end-diastolic flow demonstrated by umbilical artery (UA) Doppler velocimetry in fetal growth restriction (FGR).MethodsBetween January 1989 and June 1995, 64 consecutive, nonanomalous singletons at less than the tenth percentile for birth weight were admitted to the neonatal intensive care unit, with UA Doppler velocimetry obtained within 3 days of delivery; 54 of the 64 (84%) had placental histopathology. Umbilical artery Doppler wave forms were classified as having end-diastolic flow (n= 26), and either absent (n= 20) or reversed end-diastolic flow (n= 8). Blinded review of placental histology scored lesions in categories of intraplacental vaso-occlusion, uteroplacental vascular pathology, chronic inflammation, and coagulation.ResultsUsing cases of FGR with end-diastolic flow present as the control population, we found that absent end-diastolic flow cases had significantly more fetal stem vessels with medial hyperplasia and luminal obliteration, and cases of reversed end-diastolic flow had significantly more poorly vascularized terminal villi, villous stromal hemorrhage, “hemorrhagic endovasculitis,” and abnormally thin-walled fetal stem vessels (eachP<.005).ConclusionIn FGR, UA Doppler velocity wave forms do not demonstrate a continuum of placental lesions in which reversed end-diastolic flow reflects more severe placental histopathology than absent end-diastolic flow and enddiastolic flow present. As expected, absent end-diastolic flow cases had more occlusive lesions of the intraplacental vasculature. In reversed end-diastolic flow, lesions suggesting vascular remodeling and/or damage by pathologic conditions of intraplacental flow predominated.