Ovarian hyperstimulation following the sole administration of agonistic analogues of gonadotrophin releasing hormone

Ovarian hyperstimulation following the sole administration of gonadotrophin -releasing hormone agonists (GnRHa) is exceedingly rare. We hereby report o n two infertile patients undergoing in-vitro fertilization-embryo transfer who developed ovarian hyperstimulation under such circumstances. In both pa tients, GnRHa were administered using the 'long protocol' regimen. The firs t patient developed ovarian hyperstimulation on two occasions, with mid-lut eal depot administration of triptorelin and with early follicular triptorel in, administered as daily subcutaneous injections. In both cycles, within 2 weeks of triptorelin therapy, massive ovarian multifollicular enlargement occurred, concomitant with high serum oestradiol concentrations, which reso lved spontaneously following expectant management. The second patient devel oped ovarian hyperstimulation following daily injections of leuprolide acet ate starting at the mid-luteal phase. The final stage of ovulation was trig gered by human chorionic gonadotrophin (HCG) and 11 oocytes were retrieved. In-vitro fertilization resulted in embryo formation, but failed to result in pregnancy. The same phenomenon recurred in a subsequent cycle despite pr eventive pretreatment with an oral contraceptive. A negative GnRH test, per formed just before HCG administration, suggested than an ongoing 'flare-up effect' was unlikely to cause ovarian stimulation, Ovarian hyperstimulation can occur following the sole administration of GnRHa irrespective of the p reparation used and the administration protocol. Although spontaneous resol ution is the rule, once this condition has developed, HCG administration an d oocyte retrieval are feasible. This rare entity probably represents an ex aggerated form of ovarian cyst formation following GnRHa administration, th e underlying pathophysiology of which remains unresolved.