title: Developmental stage on day-5 and fragmentation rate on day-3 can influence the implantation potential of top-quality blastocysts in IVF cycles with single embryo transfer.
abstract: BACKGROUND
  In IVF-ICSI cycles with single embryo transfer (SET), embryo selection for transfer is of crucial importance. The present study aimed to define which embryo parameters might be related to the implantation potential of advanced blastocysts.
  
  
  METHODS
  Overall, in 203 cycles with SET, developmental characteristics of 93 implanted (group A) and 110 non-implanted (group B) advanced blastocysts of good quality were compared. The following developmental parameters were assessed in the two groups: normal fertilization, developmental stage on day 5, number of blastomeres on day 2 and on day 3, fragmentation rate on day 3, compaction on day 4 and cleavage pattern on day 2 and day 3.
  
  
  RESULTS
  Expanded blastocysts compared to full blastocysts have higher implantation potential (56.5% vs. 29.3%, p < 0.05). In group B, a higher proportion of advanced blastocysts showed between 10% and 50% anucleated fragments on day 3 than in group A (23.6 vs 11.8, P = 0.03). Advanced blastocysts with >10-50% fragments on day 3 showed a significant lower implantation (29.7%) than those with < or = 10%fragments (49.4%, P = 0.03). All the other parameters analysed were comparable for the two groups.
  
  
  CONCLUSIONS
  Developmental stage on day 5 and fragmentation rate on day 3 were related to the implantation potential of advanced blastocysts and should also be taken into account in the selection of the best advanced blastocyst for transfer.
authors.affiliation: Centre for Reproductive Medicine, University Hospital, Vrije Universiteit Brussel, Laarbeeklaan 101, B-1090 Brussels, Belgium. tidellar@yahoo.it
authors.forename: Tiziana
authors.initials: T
authors.lastname: della Ragione
authors.forename: Greta
authors.initials: G
authors.lastname: Verheyen
authors.forename: Evangelos G
authors.initials: EG
authors.lastname: Papanikolaou
authors.forename: Lisbet
authors.initials: L
authors.lastname: Van Landuyt
authors.forename: Paul
authors.initials: P
authors.lastname: Devroey
authors.forename: Andre
authors.initials: A
authors.lastname: Van Steirteghem
mesh_terms: D000328:Adult; D001755:Blastocyst / Q000166:cytology*; D046149:Embryo Culture Techniques; D010064:Embryo Implantation; D004624:Embryo Transfer; D047108:Embryonic Development; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D016015:Logistic Models; D015999:Multivariate Analysis; D010062:Ovulation Induction; D011247:Pregnancy; D018873:Pregnancy Rate