title: Increasing the probability of selecting chromosomally normal embryos by time-lapse morphokinetics analysis.
abstract: OBJECTIVE
  To study the differences in the cleavage time between chromosomally normal and abnormal embryos and to elaborate an algorithm to increase the probability of noninvasively selecting chromosomally normal embryos.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  University-affiliated infertility center.
  
  
  METHODS
  Preimplantation genetic screening patients (n = 125; n = 77 with ET), including cases of repeated implantation failure or recurrent miscarriage. A total of 504 embryos were analyzed.
  
  
  METHODS
  Embryo culture within a time-lapse system.
  
  
  METHODS
  Kinetic variables included the time to 2 (t2), 3 (t3), 4 (t4), and 5 (t5) cells as well as the length of the second (cc2 = t3 - t2) and third (cc3 = t5 - t3) cell cycle, the synchrony in the division from 2 to 4 cells (s2 = t4 - t3), and the interval t5 - t2. Implantation and clinical pregnancy rates were also analyzed.
  
  
  RESULTS
  A logistic regression analysis identified t5 - t2 (odds ratio [OR] = 2.853; 95% confidence interval [CI], 1.763-4.616), followed by cc3 (OR = 2.095; 95% CI, 1.356-3.238) as the most relevant variables related to normal chromosomal content. On the basis of these results, an algorithm for embryo selection is proposed to classify embryos from A to D. Each category exhibited significant differences in the percentage of normal embryos (A, 35.9%; B, 26.4%; C, 12.1%; D, 9.8%).
  
  
  CONCLUSIONS
  Chromosomally normal and abnormal embryos have different kinetic behavior. On the basis of these differences, the proposed algorithm serves as a tool to classify embryos and to increase the probability of noninvasively selecting normal embryos.
authors.affiliation: IVI Madrid, Madrid, Spain. Electronic address: natalia.basile@ivi.es.
authors.forename: Natalia
authors.initials: N
authors.lastname: Basile
authors.affiliation: IVI Madrid, Madrid, Spain.
authors.forename: Maria del Carmen
authors.initials: Mdel C
authors.lastname: Nogales
authors.affiliation: IVI Madrid, Madrid, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Bronet
authors.affiliation: IVI Barcelona, Barcelona, Spain.
authors.forename: Mireia
authors.initials: M
authors.lastname: Florensa
authors.affiliation: IVI Barcelona, Barcelona, Spain.
authors.forename: Marissa
authors.initials: M
authors.lastname: Riqueiros
authors.affiliation: IVIOMICS, Valencia, Spain.
authors.forename: Lorena
authors.initials: L
authors.lastname: Rodrigo
authors.affiliation: IVI Madrid, Madrid, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: García-Velasco
authors.affiliation: Instituto Valenciano de Infertilidad, Universidad de Valencia, Valencia, Spain.
authors.forename: Marcos
authors.initials: M
authors.lastname: Meseguer
mesh_terms: D000328:Adult; D002869:Chromosome Aberrations / Q000196:embryology*; D015331:Cohort Studies; D010064:Embryo Implantation; D004624:Embryo Transfer / Q000379:methods; D005260:Female; D006801:Humans; D011247:Pregnancy; D019836:Preimplantation Diagnosis / Q000379:methods*; D011336:Probability; D012189:Retrospective Studies; D059008:Time-Lapse Imaging / Q000379:methods*
keywords: Embryo kinetics; arrayCGH; chromosome; time lapse