Exploratory study assessing the effect of three gonadotrophin protocols on Controlled Ovarian Stimulation (COS) parameters and IVF outcome in oocyte donors undergoing GnRH analogue (long protocol). 1,028 donors were randomized in three groups: Group I (n= 346) only r-FSH, Group II (n= 333) only HP-hMG and Group III (n= 349) r-FSH plus HP-hMG. IVF outcome of 1,059 oocyte recipients was compared.