Improvement of IVF outcome in poor responders by discontinuation of GnRH analogue during the gonadotropin stimulation phase--a function of improved embryo quality.

PURPOSE: To assess the efficacy of a protocol involving the discontinuation of the GnRH analogue at the mid-phase of ovarian stimulation for IVF in patients with a previous poor response.

METHODS: Prospective case-control evaluation compared with same patient's previous performance. Thirty-six patients enrolled in an IVF program were treated in two consecutive cycles. The first with a standardized protocol utilizing midluteal administration of Nafarelin (N) 600 mcg/d continued throughout the stimulation phase with human menopausal gonadotropin (hMG) until follicles of 20 mm were identified by transvaginal ultrasound (Standard group). Patients with a poor response in the Standard cycle were treated in the subsequent cycle with N and hMG initially in a similar manner, then N was stopped after 5 days of hMG stimulation (N-stop group). All clinical and laboratory aspects of treatment were done in a similar fashion in both cycles, each patient acting as her own control.

RESULTS: Results were analyzed by paired t test. The change in each parameter in the N-stop cycle was expressed as the percent change as compared with the standard protocol cycle for each patient. Peak estradiol (E2) and number of aspirated oocytes were increased in the N-stop cycle (+16.9% and +28%, respectively), but insignificantly so. The percent of cleaving embryos was significantly increased by 27.9% (p = 0.03) in the N-stop cycle, as embryo morphology was improved by 22% (p = 0.02). The efficacy of gonadotropin treatment was enhanced in the N-stop cycle, as expressed by a 32.5% increase in oocytes retrieved per hMG ampoule administered (p = 0.04). Three cycles of 36 were cancelled during the N-stop cycle, whereas only one was cancelled in the standard protocol cycle. Of the 36 patients, 7 conceived in the N-stop protocol and 5 are ongoing pregnancies.

CONCLUSION: Discontinuation of GnRH-a during ovarian stimulation for IVF has a beneficial, but not statistically significant, effect on both E2 and oocyte production. Embryo cleavage rates and morphology were significantly improved, this may be due to improved oocyte quality, which may have been responsible for achieving pregnancies. The efficacy of gonadotropin treatment was enhanced when GnRH-a was discontinued. These results hint that GnRH-a may have a direct negative effect on folliculogenesis and oocytes, which is apparent especially in poor responder patients.