Adjective
extraembryonic (not comparable)
(medicine) Inside the womb, but outside the embryo.
But embryos fed by a placenta or extraembryonic yolk supply can grow very fast, and changes to relative growth rate between parts in these organisms help to produce the final overall anatomy. Source: Internet
After that, the epiblast and the hypoblast establish contact with the extraembryonic mesoderm until they cover the yolk sac and amnion. Source: Internet