Controlled ovarian hyperstimulation does not adversely affect endometrial receptivity in in vitro fertilization cycles

OBJECTIVE: To determine whether exposure of developing endometrium to supraphysiologic E2 levels during controlled ovarian hyperstimulation (COH) in IVF cycles inhibits endometrial receptivity. DESIGN: Retrospective analysis of IVF-ET and ovum donation data. SETTING: Tertiary-care teaching hospital. PATIENT(S): Four hundred ten patients <33 years of age undergoing IVF-ET and 181 anonymous ovum donors (<33 years of age) and their associated ovum recipients. MAIN OUTCOME MEASURE(S): Implantation, pregnancy, and delivery rates. RESULT(S): Ovarian response to COH (duration of stimulation, peak E2 level, area under the curve for E2 exposure, and number of oocytes retrieved) was similar for IVF-ET patients and ovum donors. Donors were younger than IVF-ET patients (mean age, 27.5 +/- 0.2 years vs. 30.4 +/- 0.1 years). A similar number of embryos with similar number of blastomeres were transferred in IVF-ET patients and ovum recipients. The fragmentation rate at time of transfer differed slightly between groups (5.2 +/- 0.2% vs. 4.3 +/- 0.3%). Implantation, pregnancy, and delivery rates did not differ between IVF-ET patients and recipients of donor oocytes. CONCLUSION(S): Exposure of the developing endometrium to controlled ovarian hyperstimulation during IVF cycles does not inhibit embryo implantation or affect pregnancy and delivery rates.