Comparison of transdermal versus oral estradiol on endometrial receptivity

Abstract

Objective: To compare the effects of oral micronized E2 with transdermal E2 on endometrial receptivity in women undergoing oocyte donation.

Design: Prospective, randomized, crossover trial. Serum E2 and P concentrations were measured on cycle days 14 and 22 (luteal day +8). Endometrial biopsies were obtained on day 22 and read in a blinded fashion for histology and beta-3-integrin expression.

Setting: University-based donor oocyte program.

Patients: Twenty-seven patients presenting for donor oocytes.

Main outcome measures: Endometrial histology and beta-3-integrin expression.

Results: The endometrial glandular histology in women given oral micronized E2 was delayed by a mean of 1.6 days in comparison to that of women given transdermal E2. Seventy percent of women given oral E2 displayed a lag > or = 4 days whereas 29.6% given transdermal E2 displayed a similar lag. Serum E2 levels were 1,194 +/- 108.8 pg/mL (mean +/- SEM; conversion factor to SI unit, 3.671) in women on oral micronized E2 and 117.4 +/- 14.0 pg/mL in those on transdermal E2.

Conclusion: The supraphysiologic serum E2 levels associated with oral micronized E2 may have a deleterious impact on endometrial receptivity. The development of more physiologic hormone replacement protocols may enhance endometrial receptivity and lead to improved clinical pregnancy rates.