title: Analysis of compaction initiation in human embryos by using time-lapse cinematography.
abstract: OBJECTIVE
  To analyze the initiation of compaction in human embryos in vitro by using time-lapse cinematography (TLC), with the goal of determining the precise timing of compaction and clarifying the morphological changes underlying the compaction process.
  
  
  METHODS
  One hundred and fifteen embryos donated by couples with no further need for embryo-transfer were used in this study. Donated embryos were thawed and processed, and then their morphological behavior during the initiation of compaction was dynamically observed via time-lapse cinematography (TLC) for 5 days.
  
  
  RESULTS
  Although the initiation of compaction occurred throughout the period from the 4-cell to 16-cell stage, 99 (86.1 %) embryos initiated compaction at the 8-cell stage or later, with initiation at the 8-cell stage being most frequent (22.6 %). Of these 99 embryos, 49.5 % developed into good-quality blastocysts. In contrast, of the 16 (13.9 %) embryos that initiated compaction prior to the 8-cell stage, only 18.8 % developed into good-quality blastocysts. Embryos that initiated compaction before the 8-cell stage showed significantly higher numbers of multinucleated blastomeres, due to asynchronism in nuclear division at the third mitotic division resulting from cytokinetic failure.
  
  
  CONCLUSIONS
  The initiation of compaction primarily occurs at the third mitotic division or later in human embryos. Embryos that initiate compaction before the 8-cell stage are usually associated with aberrant embryonic development (i.e., cytokinetic failure accompanied by karyokinesis).
authors.affiliation: Reproductive Centre, Mio Fertility Clinic, 2-1-1 Kuzumo-minami, Yonago, Japan, mfc-rep@mfc.or.jp.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Iwata
authors.forename: Keitaro
authors.initials: K
authors.lastname: Yumoto
authors.forename: Minako
authors.initials: M
authors.lastname: Sugishima
authors.forename: Chizuru
authors.initials: C
authors.lastname: Mizoguchi
authors.forename: Yoshiteru
authors.initials: Y
authors.lastname: Kai
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Iba
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Mio
mesh_terms: D004622:Embryo, Mammalian / Q000166:cytology* / Q000648:ultrastructure; D047108:Embryonic Development; D006801:Humans; D013045:Species Specificity; D059008:Time-Lapse Imaging