Just a small amount of info about pregnancy at 4 weeks.
-Your baby is about the size of a poppy seed.
-This week marks the beginning of the embryonic period.
-Right now your embryo consists of two layers (no longer three) the epiblast and the hypoblast, which all of his/her organs and body parts will develop from.
-By the end of the week the primitive placenta should be formed but will not be fully functioning yet. Until the placenta takes over your little embryo will get it’s nourishment from the yolk sac.
-The sac of amniotic fluids is already fully formed around your little embryo keeping it safe and snug.