Structural and ultrastructural defects in preovulatory endometrium of normo-ovulating infertile women with minimal or mild endometriosis.

To investigate whether a primary endometrial factor is involved in the pathogenesis of infertility in patients with minimal or mild endometriosis, we compared light, scanning, and transmission electron microscopic studies of preovulatory endometria of 15 endometriotic patients with 12 normal controls. All the women were infertile and normo-ovulating by standard criteria. Six morphometric indexes were considered. The scanning electron microscopic analysis revealed heterogeneity of the endometrial surface epithelium in 77% of the patients with endometriosis and in 16% of the controls. Glandular and stromal mitoses, basal vacuolated cells, and the ciliated:nonciliated cell ratio was significantly reduced in the endometriosis group compared with the controls. Further studies are needed to clarify the role of the observed endometrial anomalies in the pathogenesis of infertility associated with endometriosis.