title: [Outcome of embryo vitrification compared to slow freezing process at early cleavage stages. Report of the first French birth].
abstract: OBJECTIVE
  Since the end of 2010, France by "l'Agence de Biomédecine" has validated the embryo vitrification procedure as an improvement of the slow freezing method. We presented here data concerning biological and clinical outcomes from a prospective observational study where early cleavage stage good quality embryos were vitrified and warmed. We compared these results to those of a retrospective series where embryos were thawed after a slow freezing procedure (SF). We report also the first French live birth following embryo vitrification.
  
  
  METHODS
  In all, 58 cycles of frozen-thawed embryo transfers (FET) following vitrification were prospectively included and compared with 189 FET from SF method. Primary end points were the (i) survival rate (SR) (% of embryos with ≥50% post-thaw intact blastomeres), (ii) intact survival rate (ISR) (% of embryos with 100% post-thaw intact blastomeres) and (iii) survival blastomeres index (SBI) (% of post thaw intact blastomeres per survival embryo). Secondary end point was the clinical pregnancy rate (CPR) defined as the presence of an intra-uterine gestational sac with positive foetal heart beat. We report here the first French live birth following embryo vitrification.
  
  
  RESULTS
  In all, 87 and 412 embryos have been thawed following vitrification and SF, respectively. We observed a highly significant increase of SR, ISR et SBI respectively when thawing concerned vitrified embryos rather than those from SF method (98.3±13.1% vs. 77.3±32.0%, P<10(-4); 88.2±28.3% vs. 47.7±41.4%, P<10(-4); 97.7±6.1% vs. 87.3±14.4%, P<10(-4)). Furthermore, CPR were of 32.7% (19/58) and of 18.5% (35/189) following FET performed after vitrification or SF and thawing (P=0.03), respectively. The live birth of two healthy girls occurred following a caesarean section after 38 weeks of amenorrhea the 8th of August 2011.
  
  
  CONCLUSIONS
  We experienced in our study that the post-thaw survival of vitrified embryos was significantly better than those of embryos resulting from SF. Then, a better CPR per thawed embryo cycle was observed following vitrification.
authors.affiliation: Service d'histologie-embryologie-cytogénétique, pôle femme-et-enfant, CHU Jean-Verdier, Assistance Publique-Hôpitaux de Paris, avenue du 14-juillet, Bondy, France. christophe.sifer@jvr.aphp.fr
authors.forename: C
authors.initials: C
authors.lastname: Sifer
authors.forename: N
authors.initials: N
authors.lastname: Sermondade
authors.forename: C
authors.initials: C
authors.lastname: Dupont
authors.forename: C
authors.initials: C
authors.lastname: Poncelet
authors.forename: I
authors.initials: I
authors.lastname: Cédrin-Durnerin
authors.forename: J-N
authors.initials: JN
authors.lastname: Hugues
authors.forename: B
authors.initials: B
authors.lastname: Benzacken
authors.forename: R
authors.initials: R
authors.lastname: Levy
mesh_terms: D000328:Adult; D001757:Blastomeres / Q000502:physiology*; D002970:Cleavage Stage, Ovum / Q000502:physiology*; D015925:Cryopreservation / Q000379:methods*; D004624:Embryo Transfer; D005260:Female; D005602:France; D005615:Freezing; D006801:Humans; D007231:Infant, Newborn; D050498:Live Birth; D011247:Pregnancy; D018873:Pregnancy Rate; D011446:Prospective Studies; D012189:Retrospective Studies; D015996:Survival Rate; D058989:Vitrification