hemoendothelial placenta

[hē′mō-ĕn′dō-thēlē-əl]
n.
  1. A placenta in which the trophoblast becomes so attenuated that maternal blood is separated from fetal blood only by the endothelium of the chorionic capillaries.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.