Follicular phase cycle programming using estradiol in oocyte donors–a convenient and effective approach

OBJECTIVE: To study the efficacy of estradiol for cycle programming in oocyte donors when administered in the follicular phase only. DESIGN: Prospective interventional study. SETTING: Single fertility center. PATIENT(S): Ninety-three oocyte donors underwent programmed stimulation using estradiol in the follicular phase. Their previous unprogrammed cycles were used as historical controls. INTERVENTION(S): Donors received 8 mg of estradiol hemihydrate from day 2 till 1 day before the start of stimulation. MAIN OUTCOME MEASURE(S): The primary outcome measures studied were the number of oocytes retrieved, duration of stimulation, and total gonadotropin dose. The number of mature oocytes, oocyte maturation rate, fertilization rate, blastulation rate, implantation rate, and pregnancy rate were the secondary outcomes. RESULT(S): The average number of oocytes retrieved was higher in the study group (36.4 vs. 32.5). The duration of stimulation (9.22 vs. 9.21 days) and the total gonadotropin dose were similar (3,085.5 vs. 3,026 IU) between both groups. The mean number of mature oocytes retrieved was higher in the study group (30.1 vs. 26.3), but the maturation rate was similar (84.6% vs. 81.2%). The fertilization rate (77.8% vs. 78.7%), number of blastocysts, blastulation rate (32.7% vs. 33.2%), implantation rate (59.3% vs. 66.3%), and pregnancy rate (77.3% vs. 77.1%) showed no statistically significant difference. CONCLUSION(S): Estradiol usage in the follicular phase alone is an effective and convenient option for cycle programming in oocyte donors. It can yield similar mature oocytes and does not affect the clinical outcomes. Further larger sample-sized studies may be needed to validate its use which can also be extended to routine in vitro fertilization cycles. CLINICAL TRIALS REGISTRATION NUMBER: CTRI/2020/09/027815.