Effect of reduced dose of triptorelin at the start of ovarian stimulation on the outcome of IVF: a randomized study

BACKGROUND: Partial pituitary desensitization using gonadotrophin-releasing hormone (GnRH) agonists may be sufficient in women undergoing controlled o varian hyperstimulation for assisted reproduction. However, the minimal eff ective agonist dose remains to be determined. The aim of the study was to i nvestigate the effect of a reduced daily dose of triptorelin, administered at the start of ovarian stimulation, on the results of IVF and intracytopla smic sperm injection. METHODS: A total of 132 patients was randomized in tw o groups. Pituitary desensitization was obtained in group 1 (66 patients) w ith a single 3.75 mg injection (i.m.) of triptorelin. In group 2, 66 patien ts received 100 mug triptorelin daily, which was then reduced to 50 mug at the start of follicle-stimulating hormone (FSH) stimulation. RESULTS: No si gnificant differences were found in terms of pregnancy rate per transfer (3 8% in group 1 versus 34.9% in group 2), implantation rate (20.2 versus 18%) and abortion rate (8.3 versus 9.1%), The number of FSH ampoules used, as w ell as the number of days stimulation required, was significantly reduced i n group 2 (41 +/- 26 versus 46.6 +/- 25.3, P < 0.03 and 11 +/- 1.3 versus 1 1.8 +/- 1.5, P < 0.002 respectively), No significant differences were seen in oestradiol concentrations and in follicle number, in the quantity of ooc ytes collected and fertilized, or in the number of embryos obtained or tran sferred. CONCLUSION: A reduced dose of triptorelin is enough for pituitary suppression during ovarian stimulation but provides no significant improvem ent in IVF cycle outcome when compared with depot formulation. The possibil ity of a shorter treatment protocol requiring lower amounts of gonadotrophi ns should be considered in view of its economic advantage.