OBJECTIVE: Determine the most useful COH protocol in normoresponder women following gonadotropin suppression with GnRH-ant. DESIGN: Open, observational, unicenter, prospective, parallel-controlled study. MATERIALS AND METHODS: 305 normoresponder women (aged 25-40 years) undergoing first cycle of COH were assigned into four protocols with hp-hMG (Menopur, Ferring) and/or r-FSH (Gonal-f, Merck-Serono): [Group I: r-FSH from day S1 to S6 and hp-hMG after day S6; Group II: hp-hMG; Group III: r-FSH fixed-dose beetwen 150-300 IU; Group IV: r-FSH non fixed-dose. The GnRH antagonist (Ganirelix, Orgalutran, Organon) was used when a leading follicle was 14 mm in diameter until the day of ovulation induction. RESULTS: Group IV needed more stimulation days than group II [8.09 (1.25) vs 7.62 (1.17); p<0,05], however in this group the number of retrieved oocytes was higher [Group I: 9.43 (4.99) vs Group II: 8.96 (4.82) vs Group III: 8.78 (3.72) vs Group IV: 11.62 (5.80); p<0.05]. No differences were found in terms of clinical or ongoing pregnancy, however, in those patients in which two embryos were transferred, group II obtained a statistically significant higher clinical pregnancy rate than all the other groups.TablePregnancy outcomes.Group I (n=51)Group II (n=61)Group III (n=118)Group IV (n=75)r-FSH + hp-hMGhp-hMGr-FSH fixedr-FSH non fixedp-valueClinical pregnancy rate13/51 (25,5%)25/61 (41.0%)29/118 (24.6%)20/75 (26.7%)nsOngoing pregnancy rate12/51 (23.5%)22/61 (36.1%)27/118 (22.9%)20/75 (26.7%)nsClinical pregnancy rate∗Two embryos transferred.12/38 (31.6%)22/39 (56.4%)27/94 (28.7%)17/52 (32.7%)<0.05 aData are expressed as frecuency (percentage) a=Group II vs Group I,III and IV. Chi-Square Test.∗ Two embryos transferred. Open table in a new tab Data are expressed as frecuency (percentage) a=Group II vs Group I,III and IV. Chi-Square Test. CONCLUSIONS: In our study, those patients treated with hp-hMG following suppression with GnRH antagonist obtained higher clinical pregnancy rates than patients assigned to all the other groups only when two embryos were transferred.