One aspect of the present invention relates to a method of controlled ovarian hyperstimulation in a mammalian female, said method comprising administration to said female of a substance having follicle stimulating hormone activity (FSH substance) in an amount effective to stimulate follicular development and of anti-P in an effective amount to prevent a premature endogenous LH-surge, followed by the administration of a meiosis and luteinisation inducing substance (ML substance) in an amount effective to stimulate resumption of meiosis and luteinisation, and of a progestogen and/or a precursor thereof in an amount effective to prevent or suppress symptoms of progesterone antagonism and/or deficiency, wherein the progestogen and/or the precursor thereof is administered within 24 hours of the first administration of the ML substance.
Another aspect of the present invention relates to a pharmaceutical kit for use in a method of controlled ovarian hyperstimulation in mammalian females, said kit comprising a parenteral dosage unit containing a FSH substance, a parenteral or oral dosage unit containing an anti-P and a parenteral or oral dosage unit containing a progestogen and/or a precursor thereof.