Ovarian response and pregnancy outcome related to mid-follicular LH levels in women undergoing assisted reproduction with GnRH agonist down-regulation and recombinant FSH stimulation

BACKGROUND: The effect of LH levels on stimulation day 8 on ovarian response and pregnancy outcome were evaluated in women receiving pituitary down-regulation with GnRH agonists (0.8 mg Suprefact(R) s.c. daily until pituitary down-regulation and 0.4 mg/day during ovarian stimulation) and ovarian stimulation with recombinant FSH. METHODS: Blood samples were prospectively collected from a total of 207 normal women undergoing assisted reproduction and analysed retrospectively. Based on LH levels on stimulation day 8 patients were divided into four groups: <0.5, 0.51-1.0, 1.01-1.5, >1.51 IU/l. RESULTS: Estradiol levels on day 8 and estradiol per oocyte retrieved showed a highly significant correlation with LH concentrations on day 8. The total consumption of exogenous FSH and duration of gonadotrophin stimulation was inversely related to LH levels on day 8 (P < 0.002). The frequencies of fertilization and clinical pregnancies were superior in the two middle groups. Only 12% of the patients showed LH levels <0.5 IU/l, which, however, may be explained by the particular mode and doses of GnRH agonist used. CONCLUSIONS: Circulating levels of LH on day 8 have a significant impact on ovarian response and pregnancy outcome. LH should neither be too high nor too low. The mode of administration and the dose of the GnRH agonist used may determine the number of women who experience LH levels below 0.5 IU/l.