Morphometric analysis of peri-implantation endometrium in patients having excessively high oestradiol concentrations after ovarian stimulation

The present study investigated whether high oestradiol concentrations after ovarian stimulation in infertile women affect endometrial development arou nd the time of implantation. The glandular and stromal components of the en dometrium were assessed by morphometric criteria. Endometrial biopsies were taken on day 7 (+/-1) after the ovulating dose of human chorionic gonadotr ophin in stimulation cycles and on day 7 after the LH surge in natural cycl es. Women (n = 38) undergoing assisted reproduction treatment were evaluate d: 12 women in natural cycles, 11 women in stimulation cycles with oestradi ol <20 000 pmol/l and failed fertilization after oocyte collection (moderat e responders) and 15 women with an oestradiol concentration of <greater tha n or equal to>20 000 pmol/l in stimulation cycles thigh responders). High r esponders showed delayed glandular maturation and advanced stromal morpholo gy, whereas moderate responders demonstrated synchronous development of gla ndular and stromal features. In natural cycles, the glands were in phase. T he effect of excessively high oestradiol concentrations could be explained by quantitative evaluation of the endometrial biopsies as gland-stromal dys synchrony, which indicates a;deficient secretory transformation of the endo metrium that represents a suboptimal endometrial environment for implantati on. This substantiates our previous clinical observation of significantly l ower pregnancy rates in IVF cycles of women with high oestradiol concentrat ions (greater than or equal to 20 000 pmol/l).