title: Reduced blastocyst formation in reduced culture volume.
abstract: OBJECTIVE
  The aim of this prospective sibling oocyte study was to evaluate whether reduced culture volume improves blastocyst formation.
  
  
  METHODS
  Twenty-three patients with extended embryo culture until day 5 were selected for the study. After injection, 345 sibling oocytes were individually cultured in either 25 or 7 μl droplets of Origio cleavage medium under oil. On day 3 of development, embryos were transferred to droplets with the corresponding volume of Origio blastocyst culture medium. Fertilization and embryo quality on day 3 and day 5/6 were evaluated.
  
  
  RESULTS
  No statistically significant difference (p = 0.326) in fertilization rate was observed (81.3 versus 83.0 %). There was no significant difference in terms of the number of excellent and good-quality embryos obtained on day 3 between both groups (p = 0.655). Embryo culture in 25 μl droplets led to more embryos with a higher cell number when compared to 7 μl culture (p = 0.024). On day 3, 132 and 131 embryos were considered for further culture until day 5/6. Blastulation rates were significantly higher in the 25 μl group (75.0 versus 61.6 %; p = 0.017) and significantly more day 5 embryos with excellent and good quality were found in this group (54.5 versus 40.5 %; p = 0.026). Finally, the utilization rates expressed per mature oocyte (41.4 versus 29.8 %; p = 0.043), per fertilized oocyte (50.7 versus 36.6 %; p = 0.023), and per day 3 embryo undergoing extended culture to day 5/6 (54.5 versus 39.7 %; p = 0.019) were all significantly higher in the 25 μl group.
  
  
  CONCLUSIONS
  Reduced culture volume (7 μl) negatively impacts early development by reducing the cell number on day 3 and both blastocyst formation and quality.
authors: Centre for Reproductive Medicine, UZ Brussel, Laarbeeklaan 101, Brussels, Belgium. Neelke.DeMunck@uzbrussel.be.
authors: N
authors: N
authors: De Munck
authors: Centre for Reproductive Medicine, UZ Brussel, Laarbeeklaan 101, Brussels, Belgium.|Department of Obstetrics, Gynaecology and Reproductive Medicine, Hospital Universitário de Santa Maria, Avenida Professor Egas Moniz, Lisbon, 1649-035, Portugal.
authors: S
authors: S
authors: Santos-Ribeiro
authors: Centre for Reproductive Medicine, UZ Brussel, Laarbeeklaan 101, Brussels, Belgium.
authors: I
authors: I
authors: Mateizel
authors: Centre for Reproductive Medicine, UZ Brussel, Laarbeeklaan 101, Brussels, Belgium.
authors: G
authors: G
authors: Verheyen
mesh_terms: D000328:Adult; D001755:Blastocyst / Q000166:cytology* / Q000502:physiology; D003470:Culture Media; D046149:Embryo Culture Techniques / Q000379:methods*; D004622:Embryo, Mammalian / Q000166:cytology* / Q000502:physiology; D047108:Embryonic Development; D005260:Female; D005306:Fertilization / Q000502:physiology*; D005307:Fertilization in Vitro / Q000379:methods*; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009865:Oocytes / Q000166:cytology* / Q000502:physiology; D011247:Pregnancy; D011446:Prospective Studies; D013094:Spermatozoa / Q000166:cytology* / Q000502:physiology; D055815:Young Adult
chemical_list: D003470:Culture Media
keywords: Blastocyst formation; Blastocyst quality; Embryo culture; Embryo quality; Media volume