A randomised, crossover, multicentre, national, clinical trial comparing the efficacy of corifollitropin alfa versus daily recombinant FSH and HMG in the controlled ovarian stimulation of women with a poor ovarian response undergoing IVF treatments. The main objective of this study is comparing the number of oocytes obtained after the follicle puncture when using each of these two stimulation protocols. Only poor responders according to the Bologna criteria will be recruited for this trial. All participants will undergo two stimulation cycles to obtain and accumulate oocytes by vitrification. One of the cycles will be done with the corifollitropin alfa protocol and the other with daily rFSH and HMG, the order of application of these protocols will be randomised (crossover clinical trial) in each patient.