Endometrial Preparation for Frozen-thawed Embryo Transfer with or Without Pretreatment with Gonadotropin-releasing Hormone Agonist

Objective: To test the efficacy of endometrial preparation with exogenous steroids, without pretreatment with gonadotropin-releasing hormone (GnRH) agonist, in women with normal ovarian function.

Design: Prospective randomized study.

Setting: Private outpatient infertility clinic.

Patient(s): Two hundred ninety-six women undergoing frozen-thawed embryo transfer.

Intervention(s): In group 1 (146 patients), depot GnRH agonist was administered in the luteal phase; treatment with 17beta-estradiol transdermal patches at steadily increasing dosage from 100 to 300 microg was then given for at least 12 days. In group 2 (150 patients), endometrial preparation began on day 1 of menstrual cycle. The starting dose was 200 microg; this was increased to 300 microg after 7 days.

Main Outcome Measure(s): Pregnancy, abortion, implantation and cancellation rates.

Result(s): In group 2, six cycles (4%) were cancelled due to evidence of ovulation. Groups were similar in the percentage of embryos that survived freezing-thawing (77.1% in group 1 and 76.6% in group 2) and in the number of embryos transferred per patient (2.1 +/- 0.6 and 2.1 +/- 0.7, respectively). Groups 1 and 2 did not differ significantly in rates of pregnancy (19.7% and 24.1%), abortion (17.8% and 11.7%), and implantation (10.4% and 11.9%).

Conclusion(s): Endometrial preparation for frozen-thawed embryo transfer based exclusively on steroid administration appears to be as effective as the more conventional protocol involving preliminary desensitization with a GnRH agonist. This simplified protocol reduces costs, minimizes pharmacologic treatment, and increases patient compliance.