Efficiency and feasability of estradiol programming in GnRH antagonist IVF cycles

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OBJECTIVE: The GnRH antagonist (GnRH-ant) IVF cycles are convenient but the stimulation begins usually with the menses, prevents the organization of the oocyte pick-up and are thought to be less efficient than the GnRH agonist long protocol (GnRH-a). We have compared an estradiol (E2) programming GnRH-ant protocol and a GnRH-a long protocol. DESIGN: Prospective randomized study. MATERIALS AND METHODS: Patients with regular cycles were randomized in 2 arms: A = E2 GnRH-ant (n: 426) and B = GnRH-a (n: 415). The E2 GnRH-ant protocol included a pre-treatment by E2 micronized 4mg/d begun the 25th day of the previous cycle and continued until the 1st day of the stimulation (S1 which was only on Thursday in order to avoid the pick up during the week end). At S1 a transvaginal ultrasound examination was done to confirm that the follicle growing was suppressed (no follicles greater than 10mm) and to determine the antral follicle count (AFC). The antagonist (0.25mg) was introduced at D6. The ovulation triggering was completed when at least 3 follicles had reached 17mm. In the GnRH-a protocol the GnRH-a (0.1mg) started the 20th day of the previous cycle until the down regulation was confirmed; then half dose of GnRH-a 0.1mg was used from S1. In each protocol the starting dose of gonadotropins was decided according to the AFC contained between 100 to 400 IU. The triggering of ovulation is achieved by a 5,000 IU injection of HCG. RESULTS: The 2 groups are similar for the age and the range of attempt. The cancellation rate is similar in both groups. In the Group A, the follicle growing is observed in less than 2% of cases. The number of embryo transferred is similar (1.6 ± 1.03 Group A vs 1.6 ± 0.9 Group B). The number of oocytes and embryos is significantly lower in the Group A (respectively 6.8 ± 5.3 vs 7.6 ± 5.7 for the oocytes, and 3.7 ± 3.2 vs 4.1 ± 3.6 for the embryos). The pregnancy rate is similar in the groups (global pregnancy rate: 28.6% vs 27.9%) even if we compare the transfert of one top embryo (37% vs 34.8%). The number of cycles with at least one top embryo is similar between the 2 groups. CONCLUSIONS: In this study, the number of oocytes and embryos is lower in the E2 GnRH-ant arm than in the GnRH-a arm, but the pregnancy rate is similar possibly due to the use of E2 pre-treatment which improve follicle cohort harmonization as already suggested. Moreover, the E2 pre-treatment allows a IVF programming as already shown for the natural cycle.