title: Effect of oxygen concentration on human embryo development evaluated by time-lapse monitoring.
abstract: OBJECTIVE
  To evaluate, using time-lapse monitoring, the temporal influence of culture in 5% O2 or 20% O2 on human embryonic development.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  University-based fertility clinic.
  
  
  METHODS
  In vitro fertilized embryos from women aged <38 years with no endometriosis and ≥8 oocytes retrieved.
  
  
  METHODS
  Culture in 20% O2 exclusively (group 1), 20% and 5% O2 combined (group 2), or 5% O2 exclusively (group 3).
  
  
  METHODS
  Developmental rates and timing of developmental stages.
  
  
  RESULTS
  The timing of the third cleavage cycle was delayed for embryos cultured in 20% O2 (group 1) compared with embryos cultured in 5% O2 (groups 2 and 3). No difference was observed in timing of the early and full blastocyst stages. More embryos in groups 2 and 3 reached the 8-cell, early blastocyst, and full blastocyst stages than in group 1. We found that embryos in group 3 (5% O2) reached the 8-cell stage faster than embryos in group 2 (5% + 20% O2), but none of the other parameters (i.e., other time points, cumulative development, and embryo score) differed between the two groups.
  
  
  CONCLUSIONS
  Culture in 20% O2 reduces developmental rates and delays completion of the third cell cycle. The delayed development after culture in atmospheric oxygen was seen in the precompaction embryo only and therefore appears to be stage specific.
  
  
  BACKGROUND
  NCT01139268.
authors.affiliation: The Fertility Clinic, Aarhus University Hospital, Aarhus, Denmark. kirstine.kirkegaard@ki.au.dk
authors.forename: Kirstine
authors.initials: K
authors.lastname: Kirkegaard
authors.forename: Johnny Juhl
authors.initials: JJ
authors.lastname: Hindkjaer
authors.forename: Hans Jakob
authors.initials: HJ
authors.lastname: Ingerslev
mesh_terms: D000328:Adult; D001755:Blastocyst / Q000166:cytology / Q000187:drug effects; D002970:Cleavage Stage, Ovum / Q000166:cytology / Q000187:drug effects*; D046149:Embryo Culture Techniques / Q000379:methods*; D047108:Embryonic Development / Q000187:drug effects*; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D007223:Infant; D009865:Oocytes / Q000187:drug effects; D010100:Oxygen / Q000494:pharmacology*; D011247:Pregnancy; D012189:Retrospective Studies; D013997:Time Factors; D059008:Time-Lapse Imaging
chemical_list: D010100:Oxygen