Serum inhibin levels in gonadotrophin stimulated in-vitro fertilization/gamete intra-fallopian transfer cycles.

Serum inhibin concentrations of 64 cycles of in-vitro fertilization--embryo transfer (IVF-ET) or gamete intra-Fallopian transfer (GIFT) have been analysed retrospectively. No significant difference was observed in serum inhibin levels of cycles stimulated with buserelin and human menopausal gonadotrophin (HMG) or HMG alone. During the late follicular phase, serum inhibin was higher in cycles resulting in pregnancy than in cycles without a pregnancy (peak values on day +1: 8.3 versus 6.4 IU/ml, respectively). The same difference was found between stimulation cycles resulting in a viable or a non-viable pregnancy (peak values on day +1: 8.3 versus 7.5 IU/ml). However, these differences were not significant. During the early luteal phase, serum inhibin values were similar in these groups of patients. Our results indicate that the use of the gonadotrophin-releasing hormone (GnRH) analogue buserelin, in combination with HMG, for ovarian stimulation does not affect inhibin production by granulosa cells in vivo. The late follicular and early luteal concentrations of serum inhibin have to be considered unsuitable as predictors in IVF/GIFT cycles with respect to pregnancy and pregnancy outcome.