Relativity of the concept 'high responder to gonadotrophins'

Regression analysis of the proportion of unfertilized oocytes on the number of oocytes retrieved per patient was applied to three different ovarian stimulation protocols in order to establish the relativity of the concept 'high responder to gonadotrophins' for in-vitro fertilization (IVF) patients. After fitting the data to the model: probit(proportion of unfertilized oocytes) + 5 = intercept + B Log10(oocytes retrieved per patient), women with a number of oocytes retrieved greater than or equal to the value necessary to obtain 50% fertilization were defined as high responders. Exogenous gonadotrophin stimulation which was commenced after complete suppression of ovarian activity by a gonadotrophin-releasing hormone analogue (GnRHa) (long protocol) resulted in a significantly higher number of oocytes retrieved (10.15) to obtain 50% fertilization compared to a short protocol (6.84) (exogenous stimulation began 2 days after the GnRHa administration). Women stimulated without use of a GnRHa showed an intermediate response. Implantation, pregnancy and miscarriage rates showed no difference between low-moderate and high responders. These results demonstrate the relativity of the concept 'high responder to gonadotrophins' and indicate that the drawback of low fertilization in high responders could be balanced by the high number of oocytes retrieved per patient (and available embryos for transfer) and the selection of the best embryos for transfer.