Analysis of hormonal changes during combined buserelin/HMG treatment.

Changes of serum oestradiol, LH and progesterone have been analysed in view of the effect of the GnRH analogue buserelin on the late follicular and early luteal phase of cycles stimulated with combined buserelin/HMG (n = 31) in an IVF-ET/GIFT programme. Patients undergoing cycles with HMG only (n = 57) served as the control group. With the use of the GnRH analogue buserelin, a significantly higher amount of HMG (25 versus 20 ampoules; P less than 0.001) for a significantly longer stimulation period (10 versus 8 days; P less than 0.001) was necessary to achieve the same oestradiol response as seen in HMG cycles. Serum progesterone levels during a three day period before ovulation induction tended to be lower in the combined buserelin/HMG cycles than in cycles with HMG stimulation only. We did not observe any significant difference in the luteal phase progesterone levels of the buserelin/HMG and the HMG group. On the other hand, we found that an inadequate luteal phase in buserelin/HMG cycles could be avoided by HCG administration during the luteal phase. Both the elevation of basal serum LH and a premature LH rise could also be avoided by the use of buserelin.