title: Elective single cleavage-stage embryo transfer need not result in lower pregnancy rates compared to double cleavage-stage embryo transfer.
abstract: OBJECTIVE
  To confirm whether women who choose to have one fresh embryo transferred and one frozen-and-thawed embryo when needed can dramatically reduce the possibility of a multifetal pregnancy while giving themselves a better chance of achieving pregnancy.
  
  
  METHODS
  We enrolled 685 patients who were undergoing assisted reproductive technology (ART) treatment at our clinic between January 2005 and December 2008. None of the patients had a history of ART treatment, and they received either a double-embryo transfer (DET) or single-embryo transfer (SET) during this period. The outcomes of the ART and the pregnancy rates per patient were evaluated for both groups and comparisons were made.
  
  
  RESULTS
  The mean age was 35.7 +/- 0.2 years (mean +/- standard error of the mean) for all patients (n = 583) who received a fresh embryo cycle of DET. In contrast, the mean age (34.3 +/- 0.4) of all patients (n = 102) who received a fresh- or thawed-embryo transfer cycle of SET was significantly younger than the average age in the DET group (P < 0.05). The per-patient overall pregnancy rate in the SET group was an estimated 35.3%, which was significantly higher than that in the DET group (P = 0.02). However, the multifetal pregnancy rate for the DET group was significantly higher than that for the SET group (P < 0.01).
  
  
  CONCLUSIONS
  We demonstrated that women who choose to have one fresh embryo transferred and one frozen-and-thawed embryo when needed, can dramatically reduce their possibility of a multifetal pregnancy while giving themselves a better chance of achieving pregnancy.
authors.affiliation: Division of Reproductive Medicine, Sugiyama Clinic, Setagaya, Tokyo, Japan. koji@sugiyama.or.jp
authors.forename: Koji
authors.initials: K
authors.lastname: Nakagawa
authors.forename: Yayoi
authors.initials: Y
authors.lastname: Nishi
authors.forename: Rie
authors.initials: R
authors.lastname: Sugiyama
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kuribayashi
authors.forename: Rikikazu
authors.initials: R
authors.lastname: Sugiyama
authors.forename: Masato
authors.initials: M
authors.lastname: Inoue
mesh_terms: D000328:Adult; D016009:Chi-Square Distribution; D004624:Embryo Transfer / Q000379:methods*; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D011247:Pregnancy; D018873:Pregnancy Rate; D011272:Pregnancy, Multiple; D016896:Treatment Outcome