title: Prevalence, consequence, and significance of reverse cleavage by human embryos viewed with the use of the Embryoscope time-lapse video system.
abstract: OBJECTIVE
  To investigate the prevalence and potential causes of reverse cleavage (RC) by human early-cleavage embryos and its associations with embryonic development and implantation after transfer.
  
  
  METHODS
  Clinical retrospective cohort study.
  
  
  METHODS
  Private fertility treatment center.
  
  
  METHODS
  A total of 126 consecutive in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) treatment cycles, with 353 IVF and 436 ICSI embryos cultured in the Embryoscope until day 3.
  
  
  METHODS
  None.
  
  
  METHODS
  Embryo assessment on day 3, incidence of abnormal division, embryo morphokinetic parameters, and fetal heart beat.
  
  
  RESULTS
  RC, referring to either blastomere fusion or failed cytokinesis, occurred up to three times per individual embryo in 27.4% of embryos during the first three cleavage cycles. A higher incidence was associated with GnRH antagonist cycles compared with agonist cycles (odds ratio [OR] 1.683), or with ICSI compared with IVF (OR 1.600). After ICSI, sperm progressive motility was associated with RC (area under the receiver operating characteristic curve: 0.573). Compared with RC-negative embryos, a lower proportion of RC-positive embryos reached 6-cell stage or beyond by day 3 (47.7% vs. 71.7%), and were more likely to have multinucleation at the 4-cell stage (10.1% vs. 5.0%). Embryos showing RC had significantly poorer performance in both conventional grading and morphokinetic parameters, and they implanted less (0/22 vs. 29/131) than those not showing RC.
  
  
  CONCLUSIONS
  RC significantly compromised embryo development, culminating in poor implantation potential. For each embryo, it can occur on more than one occasion at any stage during the first 3 days of culture. It is associated with factors affecting both oocyte and sperm.
authors.affiliation: Fertility North, Joondalup Health Campus, Joondalup, Western Australia, Australia; School of Medical Sciences, Edith Cowan University, Joondalup, Western Australia, Australia. Electronic address: yanhe@fertilitynorth.com.au.
authors.forename: Yanhe
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Fertility North, Joondalup Health Campus, Joondalup, Western Australia, Australia.
authors.forename: Vincent
authors.initials: V
authors.lastname: Chapple
authors.affiliation: School of Medical Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Roberts
authors.affiliation: Fertility North, Joondalup Health Campus, Joondalup, Western Australia, Australia; School of Medical Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.
authors.forename: Phillip
authors.initials: P
authors.lastname: Matson
mesh_terms: D000328:Adult; D002970:Cleavage Stage, Ovum / Q000473:pathology*; D015331:Cohort Studies; D046149:Embryo Culture Techniques / Q000295:instrumentation; D004624:Embryo Transfer / Q000295:instrumentation*; D004622:Embryo, Mammalian / Q000473:pathology*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D020669:Fetoscopes; D006801:Humans; D007247:Infertility, Female / Q000453:epidemiology / Q000473:pathology* / Q000628:therapy*; D018715:Microscopy, Video / Q000295:instrumentation / Q000379:methods; D011247:Pregnancy; D011256:Pregnancy Outcome; D015995:Prevalence; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D059008:Time-Lapse Imaging / Q000295:instrumentation* / Q000379:methods; D016896:Treatment Outcome; D014904:Western Australia / Q000453:epidemiology
keywords: Reverse cleavage; abnormal cleavage pattern; embryo development; implantation; time lapse