Endometrial histology of IVF stimulated and non-stimulated endometria.

In the fertile non-stimulated endometrium at LH+2 (A) the glands are small and straight with only very early signs of secretory changes. The stroma is compact with minor signs of oedema (open arrow), and blood vessels are small (open arrow head). At hCG+2 in the fertile donor endometrium stimulated with GnRH agonist, (B & C) the glandular epithelial cells show secretory changes as evidenced by sub-nuclear vacuoles (C, closed arrows), some evidence of secretory activity can also be observed within the lumen of some endometrial glands (B, closed arrowhead). The stroma is expanded and oedematous (B, open arrow). At hCG+2 in the infertile endometrium stimulated with the GnRH antagonist protocol (D & E) a range of different endometrial cycle stage appearances presented. In some endometria (D) the endometrial glandular epithelial cells have lost their sub-nuclear vacuoles and are highly secretory (D, closed arrowheads) with glands becoming tortuous (D, arrow). The stroma is also highly oedematous and large open blood vessels are present (D, open arrowhead). Other infertile GnRH antagonist stimulated endometria (E) present with sub-nuclear vacuoles evident in the endometrial glands (E, arrows) and expanded stroma. In the endometria at hCG+2 of infertile women stimulated with the GnRH agonist protocol who did not subsequently become pregnant (F & G) a mixed picture of endometrial histology is observed. Sub-nuclear vacuoles are present in the endometrial glandular epithelial cells (F, closed arrow) with the presence of expanded oedematous stroma and large expanded blood vessels close to the luminal epithelium (F, open arrowheads). In other endometria from this group (G) the tissue histology is disturbed with highly developed, tortuous, secretory endometrial glands and highly oedematous stroma, with the tissue as a whole presenting a fragile appearance. In infertile women stimulated with the GnRH agonist protocol who subsequently became pregnant (H & I) fairly small compact endometrial glands with only early signs of secretory transformation (I, arrows) were observed at hCG+2. The stroma, while expanded in some areas is generally compact and the blood vessels are not highly developed. Endometrial histology was scored by means of a ‘normality score’ (J) with tissues of normal histology for LH+2 allocated a score of 2, tissues with somewhat changed histology allocated a score of 1 and tissues with highly altered histology allocated a score of 0. Data for fertile women are presented in black (?), data for fertile donors are presented in white (□), data for infertile GnRH antagonist are presented in horizontal lines (≡), data for infertile GnRH agonist not pregnant are presented in dark grey (?), data for infertile GnRH agonist pregnant are presented in light grey (?). Data are presented as mean ± SEM. a is significantly different from b, p<0.01; b is significantly different from c, p<0.05.