Relationships between the characteristics of endogenous luteinizing hormone surge and the degree of ovarian hyperstimulation during superovulation induction in women.

Ovarian hyperstimulation was induced in 17 normally cycling women undergoing in-vitro fertilization (IVF) and embryo transfer with clomiphene (9 cycles), clomiphene followed by pulsatile hMG (12 cycles) or clomiphene followed by pulsatile FSH (11 cycles). Hyperstimulation was greater with the combined treatments than with clomiphene alone. In all 32 cycles an endogenous LH surge occurred. The peak values and the duration of the LH surge showed significant negative correlations with the plasma oestradiol levels, the number of the follicles and the total follicular fluid volume aspirated at laparoscopy. We suggest that during superovulation induction for IVF, the endogenous LH surge is attenuated by factors which are related to the degree of ovarian hyperstimulation.