title: Clinical outcomes of elective single morula embryo transfer versus elective single blastocyst embryo transfer in IVF-ET.
abstract: OBJECTIVE
  To compare the clinical outcomes of elective single morula embryo transfer (eSMET) versus elective single blastocyst embryo transfer (eSBET) in selected patients.
  
  
  METHODS
  This study was a retrospective study which analyzed for 271 cycles in women under 37 years of age who are undergoing their first or second trial of in vitro fertilization-embryo transfer (IVF-ET) from January 2008 to December 2009. The eSMET was performed on day 4 (n = 130) and the eSBET was conducted on day 5 (n = 141).
  
  
  RESULTS
  The clinical pregnancy rate (51.5% vs. 51.8%, p = 0.97), implantation rate (52.3% vs. 52.5%, p = 0.98), and live birth rate (39.2% vs. 44.7%, p = 0.36) were similar in the eSMET and eSBET groups, respectively. The miscarriage rate of the eSMET group (23.9%) was slightly higher than that of the eSBET group (13.7%) (p = 0.12), without reaching statistical significance. There was only one case of monozygotic twin pregnancy in each group.
  
  
  CONCLUSIONS
  The clinical outcomes of day 4 eSMET were comparable to those of day 5 eSBET. Therefore, day 4 eSMET is a viable option or an alternative to day 5 eSBET, with no difference in success rates.
authors.affiliation: Maria Fertility Clinic, Samsung Fire Bldg. 2-1 Beomeo-Dong 3, Suseong-Gu, Daegu, 706-743, Republic of Korea.
authors.forename: Sang Min
authors.initials: SM
authors.lastname: Kang
authors.forename: Sang Won
authors.initials: SW
authors.lastname: Lee
authors.forename: Hak Jun
authors.initials: HJ
authors.lastname: Jeong
authors.forename: San Hyun
authors.initials: SH
authors.lastname: Yoon
authors.forename: Min Whan
authors.initials: MW
authors.lastname: Koh
authors.forename: Jin Ho
authors.initials: JH
authors.lastname: Lim
authors.forename: Seong Goo
authors.initials: SG
authors.lastname: Lee
mesh_terms: D000022:Abortion, Spontaneous; D000328:Adult; D001723:Birth Rate; D001755:Blastocyst; D010064:Embryo Implantation; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D050498:Live Birth; D009028:Morula; D010062:Ovulation Induction / Q000379:methods; D011247:Pregnancy; D018873:Pregnancy Rate; D012189:Retrospective Studies; D056826:Single Embryo Transfer / Q000379:methods*