Use of a single bolus of GnRH agonist triptorelin to trigger ovulation after GnRH antagonist ganirelix treatment in women undergoing ovarian stimulation for assisted reproduction, with special reference to the prevention of ovarian hyperstimulation syndrome: preliminary report

A new treatment option for patients undergoing ovarian stimulation is the gonadotrophin-releasing hormone (GnRH) antagonist protocol, with the possibility to trigger a mid-cycle LH surge using a single bolus of GnRH agonist, reducing the risk of developing ovarian hyperstimulation syndrome (OHSS) in high responders and the chance of cycle cancellation. This report describes the use of 0.2 mg triptorelin (Decapeptyl(R)) to trigger ovulation in eight patients who underwent controlled ovarian hyperstimulation with recombinant FSH (rFSH, Puregon(R)) and concomitant treatment with the GnRH antagonist ganirelix (Orgalutran(R)) for the prevention of premature LH surges. All patients were considered to have an increased risk for developing OHSS (at least 20 follicles greater than or equal to 11 mm and/or serum oestradiol at least 3000 pg/ml), On the day of triggering the LH surge, the mean number of follicles greater than or equal to 11 mm was 25.1 +/- 4.5 and the median serum oestradiol concentration was 3675 (range 2980-7670) pg/ml, After GnRH agonist injection, endogenous serum LH and FSH surges were observed with median peak values of 219 and 19 IU/1 respectively, measured 4 h after injection. The mean number of oocytes obtained was 23.4 +/- 15.4, of which 83% were mature (metaphase II). None of the patients developed any signs or symptoms of OHSS. So far, four clinical pregnancies have been achieved from the embryos obtained during these cycles, including the first birth following this approach. It is concluded that GnRH agonist effectively triggers an endogenous LH surge for final oocyte maturation after ganirelix treatment in stimulated cycles, Our preliminary results suggest that this regimen may prove effective in triggering ovulation and could be said to prevent OHSS in high responders, The efficacy and safety of such new treatment regimen needs to be established in comparative randomized studies.