Vasculature/CD34 and decidualization/prolactin immunostaining.

Blood vessels within the endometria of fertile women at LH+2 were generally small and compact (A). Examination of endometria from fertile women stimulated with the GnRH agonist protocol for ovum donation at hCG+2 revealed a mixture of small blood vessels and grossly enlarged blood vessels (B, arrow). Endometria from infertile women stimulated with the GnRH antagonist protocol at hCG+2 revealed a mixed picture of vascular development, with some endometria presenting grossly enlarged blood vessels (C, arrow) whereas some presented with small compact blood vessels (D). Women stimulated with the GnRH agonist protocol at hCG+2 who did not subsequently become pregnant presented with large endometrial blood vessels (E), whereas women stimulated with this protocol who did become pregnant generally presented with smaller more compact blood vessels (F). Fertile women at LH+2 had little to no immunostaining for prolactin within the endometrial stromal compartment (G). Some areas within the endometria of fertile women stimulated with the GnRH protocol for ovum donation (H), infertile women stimulated with the GnRH antagonist protocol (I) and infertile women stimulated with the GnRH agonist protocol who did not become pregnant (J) at hCG+2 demonstrated intense stromal prolactin immunostaining indicative of decidual changes. Endometria from infertile women stimulated with the GnRH agonist protocol at hCG+2 who subsequently became pregnant (K) demonstrated little stromal prolactin immunostaining, but did demonstrate glandular prolactin immunostaining indicative of secretory changes (K, arrows).