Ganirelix for luteolysis in poor responder patients undergoing IVF treatment: a Scandinavian multicenter 'extended pilot study'.

To enhance oocyte yield and pregnancy outcome in poor responder women undergoing IVF treatment, daily low dose GnRH antagonist administration was given during the late luteal phase to induce luteolysis and possibly secure a more synchronous cohort of recruitable follicles. An open extended pilot study in four Scandinavian fertility centers was done including 60 patients. Poor response was defined as when < or = 5 follicles developed in a preceding cycle following a long agonist protocol with the use of > 2000 IU FSH. GnRH antagonist (ganirelix) was given, 0.25 mg s.c. daily, from days 3 to 5 before expected start of menstruation and continued for 4-7 days. On cycle day 2-3 a starting dose of rFSH (300-400 IU/day) was given. At a leading follicle diameter of 14 mm, ganirelix administration was resumed until final oocyte maturation was induced with 10,000 IU hCG. GnRH antagonist only marginally affected the intercycle FSH rise; basal levels of FSH remained similar to those seen after 4 days of antagonist administration. The protocol effectively induced low LH levels and luteolysis, but daily administration of 350 IU rFSH (median) for 11 days only led to the collection of 3 oocytes in 49 oocyte retrievals resulting in 5 pregnancies (4 delivered). Despite GnRH antagonist administration in the late luteal phase and menstrual bleeding, FSH was not sufficiently reduced to secure a more synchronic cohort of recruitable follicles. Novel GnRH antagonists more specifically targeting FSH release may improve the stimulation results in poor responders.