title: Early-cleavage is a reliable predictor for embryo implantation in the GnRH agonist protocols but not in the GnRH antagonist protocols.
abstract: BACKGROUND
  To test if early-cleavage was a strong predictor of pregnancy in patients receiving either a GnRH agonist long protocol or a GnRH antagonist protocol for in-vitro fertilization treatment (IVF) and intracytoplasmic sperm injection (ICSI).
  
  
  METHODS
  This retrospective study included 534 patients undergoing a fresh cycle of oocyte retrieval and the day-3 embryo transfer (from 22 to 46 years old). Of the 534 patients treated, 331 received a GnRH agonist long stimulation protocol (GnRH agonist group) for ovarian stimulation and 203 patients received a GnRH antagonist protocol (GnRH antagonist group). In each group, patients who had at least one early-cleavage embryo transferred were designated as the 'early-cleavage' subgroup. Patients who had no early-cleavage embryos transferred were designated as the 'late-cleavage' subgroup.
  
  
  RESULTS
  The early cleavage rate was significantly lower in the GnRH antagonist group compared with that in the GnRH agonist group (IVF cycles: 34% versus 20%; ICSI cycles: 50% versus 37.8%, respectively, P < 0.0001). In the GnRH agonist group, the pregnancy rates were significantly higher in the early-cleavage subgroup than those in the late-cleavage subgroup (53.7% vs 33.9%, P < 0.0001). In the GnRH antagonist group, the pregnancy rates were not significantly different between the early-cleavage and late-cleavage subgroups (45.9% vs 43.8%, P > 0.05).
  
  
  CONCLUSIONS
  Early cleavage of zygote is not a reliable predictor for embryo implantation potential in using the GnRH antagonist protocol. Furthermore, the implantation rates between the GnRH agonist and GnRH antagonist groups were comparable.
authors.affiliation: Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan. molinda11@yahoo.com.tw
authors.forename: Wen-Jui
authors.initials: WJ
authors.lastname: Yang
authors.forename: Yuh-Ming
authors.initials: YM
authors.lastname: Hwu
authors.forename: Robert Kuo-kuang
authors.initials: RK
authors.lastname: Lee
authors.forename: Sheng-Hsiang
authors.initials: SH
authors.lastname: Li
authors.forename: Steven
authors.initials: S
authors.lastname: Fleming
mesh_terms: D000328:Adult; D001757:Blastomeres / Q000166:cytology; D002970:Cleavage Stage, Ovum / Q000166:cytology*; D002985:Clinical Protocols; D010064:Embryo Implantation / Q000502:physiology*; D005260:Female; D005300:Fertility Agents, Female / Q000008:administration & dosage / Q000627:therapeutic use; D007987:Gonadotropin-Releasing Hormone / Q000819:agonists* / Q000037:antagonists & inhibitors; D006801:Humans; D007247:Infertility, Female / Q000628:therapy; D008875:Middle Aged; D010062:Ovulation Induction; D011247:Pregnancy; D018873:Pregnancy Rate; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D005300:Fertility Agents, Female; D007987:Gonadotropin-Releasing Hormone