ENDOMETRIAL RESPONSES TO VARIOUS HORMONE REPLACEMENT REGIMENS IN OVARIAN FAILURE PATIENTS PREPARING FOR EMBRYO DONATION

Various regimens are recommended for replacing sex steroids in ovarian failure patients attempting donor embryo transfer. We histologically assessed endometrial biopsies obtained on simulated cycle day 26 from functionally agonadal patients (n = 19) receiving hormone replacement according to three different regimens: Regimen 1, oral micronized estradiol (E2) 2 mg days 1-5, 4 mg days 6-9, 6 mg days 10-13, 4 mg days 14-28, with progesterone vaginal suppositories, 100 mg day 15 followed by 200 mg days 16-28; Regimen 2, oral micronized E2 1 mg days 1-5, 2 mg days 6-9, 6 mg days 10-13, 2 mg days 14-28, with progesterone vaginal suppositories, 100 mg day 15 followed by 200 mg days 16-28; Regimen 3: oral micronized E2 1 mg days 1-5, 2 mg days 6-9, 6 mg days 10-13, 2 mg days 14-28, progesterone 50 mg intramuscularly delivered day 15 followed by 100 mg intramuscularly days 16-28. Biopsies were interpreted according to Noyes criteria. While all regimens resulted in variable degrees of stromal pseudodecidualization, Regimen 1 biopsies uniformly demonstrated glandular abnormalities consistent with excessive estrogen stimulation. This included aberrant maturation, intraluminal papillary excrescences and variations in epithelium size and stratification. Regimen 2 biopsies were morphologically normal in most patients, yet many manifested minor variations in gland maturity. Only Regimen 3 biopsies were consistently normal on day 26 or slightly advanced in maturation. We conclude that endometrial morphology differs according to the hormone replacement preparation and route of administration. A combination of oral E2 and intramuscular progesterone, given according to Regimen 3 design, reliably produces in-phase secretory endometrium morphologically indistinguishable from a natural spontaneous cycle.