Ovulation induction using s.c. pulsatile gonadotrophin-releasing hormone: effectiveness of different pulse...

To determine the ovarian response to a fixed dose of gonadotrophin-releasing hormone (GnRH) administered s.c. at four different pulse frequencies, 20 patients with hypothalamic amenorrhoea were treated over 41 cycles using a dose of 20 ng/kg/pulse. These patients were randomly assigned to receive GnRH at pulse frequencies of 60, 90, 120 or 180 min. GnRH was administered s.c. using portable infusion pumps. Subjects were paid volunteers with a diagnosis of hypothalamic amenorrhoea. All patients had low to less than detectable serum concentrations of luteinizing hormone and follicle stimulating hormone on 8 h serial sampling, and normal serum concentrations of prolactin and androgen, including androstenedione, testosterone and dihydroepiandrosterone sulphate. Six of the 20 patients were enrolled in the protocol to achieve a pregnancy, while 14 were volunteers using a barrier method of contraception. Highest ovulation rates were achieved using pulse frequencies of 90 and 120 min (60 and 88% of cycles respectively). Ovulation occurred significantly less often with frequencies of 60 and 180 min (12 and 38% respectively; P