Endocrine profiles and luteal function during GnRH-analogue/HMG therapy.

We have found a significant improvement of pregnancy rates after pretreatment with an agonist of gonadotrophin releasing hormone (GnRH-a). The pregnancy rate in patients treated with HMG/HCG was 17% per patient and 5.5% per cycle, in patients treated with buserelin, 25% per patient and 15% per cycle and in the triptorelin group 25% per patient and 22% per cycle. From 740 HMG/HCG cycles without GnRH-a only 66% were sufficient according to the analytical data. In 16% we found a premature LH discharge and in 18% an irregular LH fluctuation during stimulation. It is clear that gonadotrophin stimulation during pituitary suppression provokes a more intense ovarian reaction with respect to the number of follicles, as well as the endocrine activity. There are also some important practical advantages: ovarian stimulation can be started without any respect to a definite time of menstruation or of the cycle. Of further importance is the much greater flexibility in the timing of HCG administration. Finally, it will be favourable for all patients who need ovulation induction, especially for oocyte retrieval for IVF or GIFT, because no cycle has to be cancelled.