Effects of variations in serum estradiol concentrations on secretory endometrial development and function in experimentally induced cycles in normal women

Eighteen normal women underwent pituitary down-regulation with leuprolide, followed by a 10-day treatment with 0.2 mg/d transdermal estradiol (E2) with subsequent allocation to one of two 10-day estradiol regimens plus 40 mg daily intramuscular P: supraphysiologic (0.2 mg/d transdermal E2 mg/d vaginal micronized E2) or subphysiologic (no exogenous E2 treatment). Average E2 and P in the supraphysiologic, physiologic, and subphysiologic groups were 1,175.9 pg/mL and 17.5 ng/mL, 136.9 pg/mL and 21.2 pg/mL, and 23.8 ng/mL and 22.0 ng/mL, respectively, and there were no differences between groups in endometrial histology or expression of biomarkers of receptivity.