title: Early embryo development in a sequential versus single medium: a randomized study.
abstract: BACKGROUND
  The success of in vitro fertilization techniques is defined by multiple factors including embryo culture conditions, related to the composition of the culture medium. In view of the lack of solid scientific data and in view of the current general belief that sequential media are superior to single media, the aim of this randomized study was to compare the embryo quality in two types of culture media.
  
  
  METHODS
  In this study, the embryo quality on day 3 was measured as primary outcome. In total, 147 patients younger than 36 years treated with IVF/ICSI during the first or second cycle were included in this study. Embryos were randomly cultured in a sequential (group A) or a single medium (group B) to compare the embryo quality on day 1, day 2 and day 3. The embryo quality was compared in both groups using a Chi-square test with a significance level of 0.05.
  
  
  RESULTS
  At day 1, the percentage of embryos with a cytoplasmic halo was higher in group B (46%) than in group A (32%). At day 2, number of blastomeres, degree of fragmentation and the percentage of unequally sized blastomeres were higher in group B than in group A. At day 3, a higher percentage of embryos had a higher number of blastomeres and unequally sized blastomeres in group B. The number of good quality embryos (GQE) was comparable in both groups. The embryo utilization rate was higher in group B (56%) compared to group A (49%).
  
  
  CONCLUSIONS
  Although, no significant difference in the number of GQE was found in both media, the utilization rate was significantly higher when the embryos were cultured in the single medium compared to the sequential medium. The results of this study have a possible positive effect on the cumulative cryo-augmented pregnancy rate.
  
  
  BACKGROUND
  NCT01094314.
authors.affiliation: Leuven University Fertility Centre, UZ Gasthuisberg, Campus Gasthuisberg, Herestraat 49, 3000 Leuven, Belgium. goedele.paternot@uzleuven.be
authors.forename: Goedele
authors.initials: G
authors.lastname: Paternot
authors.forename: Sophie
authors.initials: S
authors.lastname: Debrock
authors.forename: Thomas M
authors.initials: TM
authors.lastname: D'Hooghe
authors.forename: Carl
authors.initials: C
authors.lastname: Spiessens
mesh_terms: D000328:Adult; D003470:Culture Media / Q000494:pharmacology*; D046149:Embryo Culture Techniques / Q000379:methods*; D004624:Embryo Transfer; D004622:Embryo, Mammalian / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D047108:Embryonic Development / Q000187:drug effects / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008297:Male; D011247:Pregnancy; D018873:Pregnancy Rate; D011786:Quality Control; D020554:Sperm Injections, Intracytoplasmic
chemical_list: D003470:Culture Media