[Hyperstimulation for in vitro fertilization with the "step-down" technique. Preliminary results from a prospective...

Twenty six normo-ovulatory patients < 38 years with tubal or idiopathic infertility and normal sperm were treated for IVF by FSH +/- hMG and randomized into four groups: with and without LHRH agonist, "step-up" or "step-down" stimulation. In the step down protocol, after 4 days with 4 amps plasmatic FSH reached its top level, then decreased. Despite reduction to only two amps, estradiol continued to increase in all the 5 women without agonist, whereas 3/7 with the long protocol were considered as low responders and stopped. The fertilization/cleavage rate was 69.2% in step-down and 45.7% in step-up (p < 0.04) with the short protocol, and respectively 65.6% and 41.9% (p < 0.03) with the long one. The pregnancy rate was equivalent in all groups.