Therefore the aim of this study is to prove that both drugs are comparable in the treatment of these patients. The test substances are marketed in Spain (Fostipur and Meriofert, respectively) with an indication for use in these patients. In this study both medicines will be administered in a randomized way under the usual conditions in which it is used in routine clinical practice to compare the quantity of mature oocytes respect to the total oocytes obtained, as a primary outcome measure.