Dynamics of pituitary down-regulation and ovarian response to controlled stimulation in in vitro fertilization cycles.

The effect of the daily GnRH agonist administration on LH levels and ovarian response after down-regulation was investigated in 2 groups of women who received recombinant FSH versus hMG. The results showed that the pituitary gland remained responsive to the daily buserelin by producing pulses of LH, despite down-regulation in both groups; however, the patients whose condition is profoundly down-regulated may need exogenous LH to improve their response.