Recombinant follicle stimulating hormone (rFSH; Puregon) in assisted reproduction: more oocytes, more pregnancies. Results from five comparative studies.

The clinical assessment of recombinant follicle stimulating hormone (rFSH; Puregon) in assisted reproduction technologies such as in-vitro fertilization (IVF) has probably been the most extensive clinical trial programme ever performed for the evaluation of a new fertility drug. It started with a pilot study to evaluate the potential of rFSH to stimulate the ovaries in the absence of luteinizing hormone (LH) using various gonadotrophin-releasing hormone (GnRH) agonists. After it became clear that FSH-induced steroidogenesis was not jeopardized even after severe pituitary suppression, comparisons between rFSH and urinary FSH or human menopausal gonadotrophins were made using different GnRH agonists or no agonists at all. In addition, the effects of the route of administration (s.c. or i.m.) were assessed. The study with the strongest statistical power to truly assess clinically relevant differences between rFSH and urinary FSH included approximately 1000 patient cycles. It indicated that after rFSH treatment, significantly more oocytes were retrieved, more embryos obtained and, as a result, more pregnancies achieved when the results of the cryoprogramme were included.