title: Cumulative live birth rate after two single frozen embryo transfers (eSFET) versus a double frozen embryo transfer (DFET) with cleavage stage embryos: a retrospective cohort study.
abstract: OBJECTIVE
  According to the latest ART report for Europe, about 13% of pregnancies after frozen embryo transfer are multiple. Our objective was to analyse the impact on the multiple pregnancy rate of two eSFET (elective single frozen embryo transfers) versus a DFET (double frozen embryo transfer) in women aged under 38 years, who had not achieved pregnancy in their fresh transfer and who had at least two vitrified embryos of A/B quality.
  
  
  METHODS
  This study was conducted from January 2010 to June 2013 at a public hospital. The couples were divided into three groups. Group DFET: the first cryotransfer of two embryos (105 women); cSFET group: the only cryotransfer of a single vitrified embryo (60 women); eSFET group, individually vitrified embryos: 20 patients included in a clinical trial of single-embryo fresh and frozen transfer and 21 patients who chose to receive eSFET.
  
  
  RESULTS
  The clinical pregnancy rate was 38.1% in the DET group and the cumulative clinical pregnancy rate was 43.3% in the eSFET group. There were no significant differences between the DFET and eSFET groups (30.0 vs 34.1%) in cumulative live birth delivery rate. The rate of multiple pregnancies varied significantly between the DFET and eSFET groups (32.5 vs 0%, p < 0.05).
  
  
  CONCLUSIONS
  For good-prognosis women aged under 38 years, taking embryo quality as a criterion for inclusion, an eSFET policy can be applied, achieving acceptable cumulative clinical pregnancy and live birth rates and reducing multiple pregnancy rates.
authors.affiliation: U. Reproducción, UGC de Obstetricia y Ginecología, Hospital Universitario Virgen de las Nieves, Instituto de Investigación Biosanitaria de Granada, Granada, Spain, marisalopezregalado@gmail.com.
authors.forename: Ma Luisa
authors.initials: ML
authors.lastname: López Regalado
authors.forename: Ana
authors.initials: A
authors.lastname: Clavero
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Gonzalvo
authors.forename: María
authors.initials: M
authors.lastname: Serrano
authors.forename: Luis
authors.initials: L
authors.lastname: Martínez
authors.forename: Juan
authors.initials: J
authors.lastname: Mozas
authors.forename: Fernando
authors.initials: F
authors.lastname: Rodríguez-Serrano
authors.forename: Juan
authors.initials: J
authors.lastname: Fontes
authors.forename: Bárbara
authors.initials: B
authors.lastname: Romero
authors.forename: Jose A
authors.initials: JA
authors.lastname: Castilla
mesh_terms: D000328:Adult; D001723:Birth Rate; D002970:Cleavage Stage, Ovum; D015331:Cohort Studies; D015925:Cryopreservation; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D011247:Pregnancy; D018873:Pregnancy Rate; D011272:Pregnancy, Multiple / Q000502:physiology; D056826:Single Embryo Transfer; D058989:Vitrification