Effects of short-term GnRH agonist--human menopausal gonadotrophin stimulation in patients pre-treated with progestogen.

The recent use of gonadotrophin-releasing hormone agonist in a short-term regimen has allowed the effectiveness of human menopausal gonadotrophin (HMG) stimulation to be markedly improved. It seems to be related to the flare-up effect of the agonist in the early follicular phase of the cycle. However, individual hormonal responses to the agonist are quite variable and four patterns of oestradiol secretion have been described. The present study indicates that in women pre-treated with progestogen, only two patterns of serum oestradiol are observed in the flare-up period, with a significant increase in 57% of patients. Significant correlations are observed between oestradiol values and the endogenous gonadotrophin surge (positively with luteinizing hormone, r = 0.38; P less than 0.05 and negatively with follicle stimulating hormone, r = 0.48; P less than 0.005). Furthermore, there was a significant relationship between the hormonal flare-up and the ovarian parameters following HMG stimulation. In conclusion, in progestogen-pre-treated women, the serum oestradiol level during the flare-up period is a reliable index to predict subsequent effectiveness of ovarian stimulation with HMG.