A flexible protocol for artificial preparation of the endometrium without prior gonadotropin-releasing hormone agonist suppression in women with functioning ovaries undergoing frozen-thawed embryo transfer cycles

Objective: To present our experience with a flexible and convenient protocol for artificial endometrial preparation without prior GnRH agonist suppression in patients with functioning ovaries undergoing frozen ET. Design: Case series. Setting: An IVF unit in a university hospital. Patient(s): All patients who underwent IVF with embryo cryopreservation from December 1997 to June 1998 and requested transfer of their frozen-thawed embryos. Intervention(s): Controlled endometrial preparation for ET entailed the use of a fixed dose of 6 mg/d of micronized E 2 started on day 1 of the cycle, followed by concomitant administration of micronized P placed in the vagina. Main Outcome Measure(s): Hormonal and endometrial profiles throughout the cycle, pregnancy rate per ET, implantation rate, and pregnancy outcome. Result(s): Of 185 treatment cycles in 140 patients, 8 cycles (4.3%) were canceled. In another 2 cycles, no embryos were suitable for transfer. For the remaining 175 ET cycles, the calculated pregnancy rate and implantation rate were 21.7% and 9%, respectively. The proliferative phase could be extended up to 20 days but was a mean (±SD) of 15 ± 1.9 days. Conclusion(s): For patients with functioning ovaries, controlled endometrial preparation for the transfer of frozen-thawed embryos can be done successfully by using oral E 2 from day 1 of the cycle followed by P preparation. Prior suppression with GnRH agonist is not necessary.