title: Cryopreserved blastocyst transfer: impact of gonadotropin-releasing hormone agonist versus antagonist in the previous oocyte retrieval cycles.
abstract: OBJECTIVE
  To assess any detrimental effect of gonadotropin-releasing hormone (GnRH) antagonists on oocyte quality and embryo development by comparing the outcome of cryopreserved-thawed blastocyst transfers for cycles using a GnRH agonist or GnRH antagonist protocol for the controlled ovarian stimulation in the oocyte retrieval cycle.
  
  
  METHODS
  Retrospective comparative study.
  
  
  METHODS
  Private IVF center.
  
  
  METHODS
  Seventy-seven women who underwent cryopreserved-thawed blastocyst transfer.
  
  
  METHODS
  The patients were divided into two groups based on whether they had been treated using a GnRH agonist long protocol (n = 44) or a GnRH antagonist multiple-dose protocol (n = 33) during the previous oocyte retrieval cycle. Cryopreserved-thawed blastocysts were transferred after endometrial preparation without pituitary suppression using a GnRH agonist.
  
  
  METHODS
  Implantation and clinical pregnancy rates.
  
  
  RESULTS
  The postthaw survival rate and numbers of good quality blastocysts transferred were similar for the GnRH agonist and GnRH antagonist groups. Implantation and pregnancy rates for cryopreserved-thawed blastocyst transfer for the GnRH agonist group versus the GnRH antagonist group were 21.0% (25 of 119) versus 29.0% (27 of 93) and 38.6% (17 of 44) versus 51.5% (17 of 33), respectively, which was not statistically significantly different.
  
  
  CONCLUSIONS
  No difference was found in terms of implantation and pregnancy rates when a GnRH agonist or GnRH antagonist was used in the previous oocyte retrieval cycle. Our results suggest that GnRH antagonists do not have a detrimental effect on oocyte quality or embryo development.
authors.affiliation: Department of Obstetrics and Gynecology, College of Medicine, Seoul National University, Seoul, Korea.
authors.forename: Jung Ryeol
authors.initials: JR
authors.lastname: Lee
authors.forename: Young Sik
authors.initials: YS
authors.lastname: Choi
authors.forename: Byung Chul
authors.initials: BC
authors.lastname: Jee
authors.forename: Seung-Yup
authors.initials: SY
authors.lastname: Ku
authors.forename: Chang Suk
authors.initials: CS
authors.lastname: Suh
authors.forename: Ki Chul
authors.initials: KC
authors.lastname: Kim
authors.forename: Won Don
authors.initials: WD
authors.lastname: Lee
authors.forename: Seok Hyun
authors.initials: SH
authors.lastname: Kim
mesh_terms: D000328:Adult; D015925:Cryopreservation / Q000379:methods*; D004624:Embryo Transfer / Q000379:methods*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000819:agonists* / Q000037:antagonists & inhibitors* / Q000502:physiology; D006801:Humans; D054315:Oocyte Retrieval / Q000379:methods*; D011247:Pregnancy; D018873:Pregnancy Rate; D012189:Retrospective Studies
chemical_list: D007987:Gonadotropin-Releasing Hormone