Method of treating or preventing infertility in a female mammal and pharmaceutical kit for use in such method

1. A method of controlled ovarian hyperstimulation in a mammalian female, said method comprising administering to said female a combination of (i) an FSH substance selected from the group consisting of uFSH and recFSH in an effective amount to stimulate follicular development and (ii) a steroid in an effective amount to inhibit or suppress the secretion of luteinising hormone, the steroid being selected from the group consisting of:

substances represented by the following formula

in which formula R 1 , R 2 , R 3 , and R 4 independently are a hydrogen atom, a hydroxyl group or an alkoxy group with 1-5 carbon atoms; each of R 5 , R 6 , and R 7 is a hydroxyl group; no more than three of R 1 , R 2 , R 3 , and R 4 are hydrogen atoms;

derivatives of the aforementioned steroid substances wherein the hydrogen atom of at least one of the hydroxyl groups has been substituted by an acyl radical of a hydrocarbon carboxylic, sulfonic or sulfamic acid of 1-25 carbon atoms; tetrahydrofuranyl; tetrahydropyranal; or a straight or branched chain glycosidic residue containing 1-20 glycosidic units per residue; and

mixtures of one or more of the aforementioned steroid substances or derivatives.

2. The method according to claim 1 , wherein R 3 represents a hydroxyl group or an alkoxy group.

3. The method according to claim 1 , wherein at least three of R 1 , R 2 , R 3 and R 4 represent hydrogen atoms.

4. The method according to claim 1 , wherein the steroid is administered in a daily dose of between 0.5 and 200 mg.

5. The method according to claim 1 , wherein the steroid is administered orally.

6. The method according to claim 1 , wherein the steroid is administered in an effective amount to prevent a premature endogenous LH-surge.

7. The method according to claim 1 , further comprising administering a meiosis and luteinisation inducing substance (ML substance) having or inducing luteinising hormone activity in an amount effective to stimulate resumption of meiosis and luteinisation.

8. The method according to claim 6 further comprising:

a. harvesting one or more ova from ovarian follicles;

b. fertilising one or more ova in vitro;

c. transferring the resulting embryo into the uterus of a mammalian female.

9. The method according to claim 7 , wherein the ML substance is selected from the group consisting of recombinant LH, urinary chorionic gonadotropin (uCG), recombinant CG, gonadotropin releasing hormone (GnRH), GnRH agonists and mixtures thereof.

10. A pharmaceutical kit for use in a method of controlled ovarian hyperstimulation in mammalian females, said kit comprising a parenteral or oral dosage unit containing a FSH substance selected from the group consisting of uFSH and recFSH and a parenteral or oral dosage unit containing a steroid selected from the group consisting of:

substances represented by the following formula

in which formula R 1 , R 2 , R 3 , and R 4 independently are a hydrogen atom, a hydroxyl group or an alkoxy group with 1-5 carbon atoms; each of R 5 , R 6 , and R 7 is a hydroxyl group; no more than three of R 1 , R 2 , R 3 , and R 4 are hydrogen atoms;

derivatives of the aforementioned steroid substances wherein the hydrogen atom of at least one of the hydroxyl groups has been substituted by an acyl radical of a hydrocarbon carboxylic, sulfonic or sulfamic acid of 1-25 carbon atoms; tetrahydrofuranyl; tetrahydropyranal; or a straight or branched chain glycosidic residue containing 1-20 glycosidic units per residue; and

mixtures of one or more of the aforementioned steroid substances or derivatives.

11. The pharmaceutical kit according to claim 10 , wherein the FSH substance is in an amount which is equivalent to a subcutaneous dose of between 50 and 1000 I.U. recFSH.