title: Modified natural cycle using GnRH antagonist can be an optional treatment in poor responders undergoing IVF.
abstract: OBJECTIVE
  To investigate the efficacy of gonadotrophin-releasing hormone (GnRH) antagonist supplementation during natural cycles in poor responders undergoing IVF-ET treatment.
  
  
  METHODS
  We retrospectively evaluated 540 cycles of 433 suitable patients who were divided by treatment protocol into modified natural, antagonist, and long agonist groups. There were 52 modified natural cycles with GnRH antagonist supplementation, 200 stimulated cycles with GnRH antagonist, and 288 long GnRH agonist cycles. Cycle characteristics and treatment outcomes were compared between the groups.
  
  
  RESULTS
  The mean number of oocytes retrieved in the modified natural group was significantly lower than in the stimulated antagonist and long agonist groups (1.4 +/- 0.5 vs. 2.3 +/- 1.1 and 2.5 +/- 1.1, respectively, p < 0.05). The respective implantation and pregnancy rates were 10% and 14.3%, 6.75% and 10.2%, and 7.4% and 10.6%. Cycle outcome and cycle properties were similar.
  
  
  CONCLUSIONS
  Modified natural IVF cycle with GnRH antagonist supplementation is a feasible alternative to ovarian stimulation protocols in poor responders.
authors.affiliation: IVF Unit - Department of Obstetrics and Gynecology, Chaim Sheba Medical Center, Tel-Hashomer, Israel. shaieliz@netvision.net.il
authors.forename: Shai E
authors.initials: SE
authors.lastname: Elizur
authors.forename: Dilek
authors.initials: D
authors.lastname: Aslan
authors.forename: Adrian
authors.initials: A
authors.lastname: Shulman
authors.forename: Boaz
authors.initials: B
authors.lastname: Weisz
authors.forename: David
authors.initials: D
authors.lastname: Bider
authors.forename: Jehoshua
authors.initials: J
authors.lastname: Dor
mesh_terms: D000328:Adult; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D006727:Hormone Antagonists / Q000627:therapeutic use*; D006801:Humans; D009865:Oocytes; D010060:Ovulation / Q000502:physiology; D010062:Ovulation Induction / Q000379:methods*; D011247:Pregnancy; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D006727:Hormone Antagonists; D007987:Gonadotropin-Releasing Hormone; C062876:cetrorelix