Endometrium in in-vitro fertilization cycles: morphological and functional differentiation in the implantation phase.

Secretory differentiation of endometrium after multiple follicular stimulation using gonadotrophin releasing hormone and human menopausal gonadotrophin has been studied both histologically and immunohistochemically in 30 women undergoing in-vitro fertilization treatment. None had embryo transfer. Patients were randomly allocated to receive luteal phase support with a single dose of human chorionic gonadotrophin. The latter failed to produce any significant enhancement of endometrial structure or secretions. Appropriate glandular morphology was present in a greater proportion of those who were successfully stimulated than those who responded poorly. However, defective secretion of the cycle-dependent component studied, using monoclonal antibody D9B1, was demonstrated in two-thirds of cases regardless of the ovarian response. Early vascular maturation in the stroma was a common finding, and was thus considered as a feature of structural modulation of these endometria.