title: ART results with frozen oocytes: data from the Italian ART registry (2005-2013).
abstract: OBJECTIVE
  This study is a retrospective collection of aggregated data from all the Italian ART centers reporting to the Italian National Register from cycles started between January 2005 and December 2013.
  
  
  METHODS
  Data from both slow freezing (SF) and vitrification (V) were assessed for the period 2007-2013, while during the years 2005-2006 cryopreservation was exclusively performed by SF.
  
  
  RESULTS
  In the study period, a total of 2,526,024 oocytes were retrieved (from 378,543 retrievals), of which 1,346,061 (53.3 %) were inseminated in fresh cycles and 214,481 (8.5 %) were cryopreserved. Cryopreserved oocytes were used in 24,173 cycles yielding 19,453 transfer cycles (80.5 % of the thawing/warming cycles) and 3043 clinical pregnancies (15.6 % per transfer). A significant difference in implantation (8.7 vs 12.9 % OR 1.30 CI 1.20-1.40) and pregnancy rates per transfer (12.2 vs 14.9 % OR 1.34 CI 1.23-1.46) was found between SF and V. Complete outcome data was available for 2708 pregnancies (89.8 %), leading to 1882 deliveries and 2152 live births. Neonatal major congenital anomalies were 0.9 % (20/2152).
  
  
  CONCLUSIONS
  A wide variation in pregnancy rates were found among different centers and lower rates were reported in donor cycles and in centers with more experience.
authors.affiliation: Department of Gynaecology, Division of Gynaecology and Reproductive Medicine, Humanitas Fertility Center, Humanitas Research Hospital, Rozzano, Milan, Italy. paolo.levi_setti@humanitas.it.
authors.forename: Paolo Emanuele P E
authors.initials: PE
authors.lastname: Levi-Setti
authors.affiliation: Tecnobios Procreazione, Bologna, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Borini
authors.affiliation: Department of Obstetrics, Gynaecology and Reproductive Sciences, Yale University, School of Medicine, New Haven, CT, USA.
authors.forename: Pasquale
authors.initials: P
authors.lastname: Patrizio
authors.affiliation: ART Italian National Register, National Centre for Epidemiology, Surveillance and Health Promotion, National Health Institute, Rome, Italy.
authors.forename: Simone
authors.initials: S
authors.lastname: Bolli
authors.affiliation: ART Italian National Register, National Centre for Epidemiology, Surveillance and Health Promotion, National Health Institute, Rome, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Vigiliano
authors.affiliation: ART Italian National Register, National Centre for Epidemiology, Surveillance and Health Promotion, National Health Institute, Rome, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: De Luca
authors.affiliation: ART Italian National Register, National Centre for Epidemiology, Surveillance and Health Promotion, National Health Institute, Rome, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Scaravelli
mesh_terms: D000328:Adult; D015925:Cryopreservation; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007558:Italy; D050498:Live Birth; D009865:Oocytes / Q000254:growth & development* / Q000637:transplantation; D011247:Pregnancy; D027724:Reproductive Techniques, Assisted / Q000639:trends*; D012189:Retrospective Studies; D058989:Vitrification
keywords: ART registry; Congenital anomalies; Cumulative ART pregnancy rate; Oocyte freezing; Safety in ART