Vascular response of the fetal placenta to local occlusion of the maternal placental vasculature.
Local regulation of fetal placental blood flow was studied in 6 near-term sheep. Maternal blood flow was reduced or eliminated to 6-17% of the placenta by ligation or embolization with non-radioactive microspheres. Maternal and fetal placental blood flows were measured, using radioactively-labelled microspheres, before and after vascular occlusion. The change in fetal placental blood flow was significantly different in the occluded as compared to the non-occluded cotyledons. Occlusion of the maternal placental vasculature was associated with a 40% decline in the adjacent fetal placental flow after 24 h. These data support the concept of a local regulatory interaction between fetal and maternal placental circulations wherein fetal placental blood flow is dependent upon the adjacent maternal flow.
D000818:Animals; D005260:Female; D005333:Fetus / Q000502:physiology*; D008863:Microspheres; D010920:Placenta / Q000098:blood supply*; D010922:Placenta Diseases / Q000503:physiopathology*; D011247:Pregnancy; D012039:Regional Blood Flow; D012756:Sheep; D014599:Uterus / Q000502:physiology