Gonadotropin therapy for the treatment of anovulation and for ovarian hyperstimulation for IVF.

Knowledge of the mechanisms of single dominant follicle selection has led to the development of a novel and effective ovulation induction regimen for anovulatory women; the step down protocol. This commences with a fixed high gonadotropin dose followed by several decremental steps. For some patients the initial dose is too high, risking ovarian hyperstimulation syndrome. A major improvement to this approach would, therefore, be the ability to use initial screening characteristics to assess the individual FSH threshold beforehand. For IVF treatment, interfering in the process of single dominant follicle selection in ovulatory women by late follicular phase administration of low doses of FSH may result in a significantly reduced duration of stimulation and amounts of exogenous FSH preparations used. Less monitoring would be required and chances for short-term complications or long term risks may be reduced.