title: Validity for assisted hatching on pregnancy rate in assisted reproductive technology: analysis based on results of Japan Assisted Reproductive Technology Registry System 2010.
abstract: OBJECTIVE
  The aim of this study was to assess the efficacy of assisted hatching (AH) in assisted reproductive technology (ART) treatment.
  
  
  METHODS
  In this retrospective observational study, the data of patients who were registered in the National ART Registry System of Japan between January and December 2010 were analyzed. The descriptive statistics and validity of AH in fresh embryo transfer (ET) and frozen-thawed ET were assessed by using multiple logistic regression analyses.
  
  
  RESULTS
  From a total of 105,450 single ET, 46,029 (43.7%) cycles underwent AH. A total of 9737 (21.3%) and 36,292 (60.9%) cycles underwent AH from 45,818 fresh single ET and 59,632 frozen-thawed single ET, respectively. In the fresh ET patients that underwent AH, the clinical pregnancy and live birth rate were significantly decreased in patients of all ages compared with that of the non-AH group. In the frozen-thawed ET patients, there was no significant difference in pregnancy and live birth rate between the AH group and the non-AH group.
  
  
  CONCLUSIONS
  AH treatment was more frequently performed in frozen-thawed ET patients than in fresh ET patients, and in the blastocyst stage than in the early cleavage stage. A significantly decreased pregnancy and live birth rate was observed in the fresh ET patients who underwent AH. In the frozen-thawed ET patients who underwent AH, improvement in the clinical pregnancy and live birth rate was not observed. Further studies on the indication and application of AH in ART treatment are required.
authors.affiliation: Division of Reproductive Medicine, National Center for Child Health and Development.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakasuji
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Saito
authors.forename: Ryuichiro
authors.initials: R
authors.lastname: Araki
authors.forename: Aritoshi
authors.initials: A
authors.lastname: Nakaza
authors.forename: Akira
authors.initials: A
authors.lastname: Kuwahara
authors.forename: Osamu
authors.initials: O
authors.lastname: Ishihara
authors.forename: Minoru
authors.initials: M
authors.lastname: Irahara
authors.forename: Toshiro
authors.initials: T
authors.lastname: Kubota
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Yoshimura
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Sakumoto
mesh_terms: D000328:Adult; D004624:Embryo Transfer; D005260:Female; D006801:Humans; D007564:Japan; D050498:Live Birth; D011247:Pregnancy; D018873:Pregnancy Rate; D012042:Registries; D012189:Retrospective Studies; D015044:Zona Pellucida
keywords: National Assisted Reproductive Technology Registry System; assisted hatching; clinical pregnancy rate; fresh embryo transfer; frozen-thawed embryo transfer