During week 2 of development, the embryoblast receives its nutrients
During week 2 of development, the embryoblast receives its nutrients from endometrial blood vessels, endometrial glands, and decidual cells diffusion. Diffusion of nutrients does not pose a problem, given the small size of the blastocyst during week 2. Although the beginnings of a uteroplacental circulation are established by end of week 2, no blood vessels have yet formed in the extraembryonic mesoderm to carry nutrients directly to the embryoblast (this occurs in week 3 - day17).
Diffusion
Osmosis
Reverse osmosis
Fetal capillaries
Development period- week 1,2,3,4