Recombinant LH Supplementation Timing Strategies (From Day 1 or Day 6) to a Standard GnRH Agonist Long Protocol in Subsequent COS Cycle of Older Patients With Unexpected Poor or Suboptimal Ovarian Response

A randomized, controlled, pilot study, for Patients ≥ 35 years and \< 40 years old with sufficient ovarian reserve parameters (AFC≥ 5), but showed an unexpected poor or suboptimal ovarian response(defined as ≤ 9 retrieved oocytes in previous full-stimulation cycle, but not get live birth after all embryos were used ). In order to get better oocyte number and quality in the new COS cycle, we will compare LH supplementation from beginning with from middle of stimulation in GnRH-a long protocol.