Endometrial receptivities after leuprolide suppression and gonadotropin stimulation: histology, steroid receptor concentrations, and implantation rates.

The effect of markedly supraphysiologic levels of E2 and P4 on the endometrium was assessed by examining endometrial histology, E2 and P4 receptor concentrations, and embryo implantation rates in IVF cycles with and without leuprolide use. Results suggest that 1) the high ovarian response common in leuprolide pretreated cycles can advance endometrial histology, but only up to a certain limit, 2) P4 greater than 25ng/ml or E2 greater than 200pg/ml on the day of transfer was associated with non-lagging endometria, 3) implantation rate in high response cycles is not impaired and may be increased, 4) earlier P4 supplementation in low response cycles may be beneficial, 5) extraordinarily high response (E2 greater than 5000pg/ml) may be detrimental to implantation, and 6) the optimal histology for implantation appears to be at least day 16.