 It appears that the effects of these eu-FEDS associated glycoproteins are manifested only during implantation and the very early development of the embryo.In humans, the expression of such glycoproteins greatly decreases toward the end of the first trimester.Therefore, more highly targeted mechanisms of immune suppression (such as the expression of the enzyme indoleamine dioxygenase (IDO)) are likely employed by the fetus during the subsequent stages of development.