In the fourth week the embryo has the aspect and size of a bean. It already has the three main tissue layers from which the rest of organs will be produced.
Read the full article on: 4 Weeks Pregnant: Embryo Implantation in the Uterus. ( 53).
By Paloma de la Fuente Vaquero M.D., Ph.D., M.Sc. (gynecologist), Zaira Salvador B.Sc., M.Sc. (embryologist) and Marie Tusseau (invitra staff).
Last Update: 11/05/2018
