title: A prospective trial of blastocyst culture and transfer.
abstract: BACKGROUND
  The aim of this study was to evaluate the effectiveness of the blastocyst culture method compared with the conventional day 3 transfer method using a prospective trial.
  
  
  METHODS
  A total of 235 patients with 273 cycles were evaluated for a period of almost 1 year. Depending upon the sequence in which the ovum retrieval was performed, patients were prospectively assigned (alternate allocation) to a culture period of 3 or 5 days duration. Embryos were transferred either on day 3 (after culture in human tubal fluid) or on day 5 (after culture in sequential media).
  
  
  RESULTS
  The pregnancy rates after embryo transfer on days 3 and 5 were similar at 26.5 and 25.9% respectively. Among the day 5 embryo transfer group, patients were divided into three groups corresponding to three sequential media. The pregnancy rates were 32.0% using Irvine blastocyst medium, 6.9% using G1.2/G2.2 and 32.4% using Cook blastocyst medium.
  
  
  CONCLUSIONS
  The results of our study were not as successful as previous studies had been. Additionally, there may have been problems in day 5 embryo transfer, such as choosing the sequential media, quality control, contamination and so on. From the results of this study, it appears that day 5 embryo transfer has no advantages for ordinary patients of assisted reproductive technology.
authors.affiliation: St Luke Clinic, 5 Tsumori-Tomioka, Oita City 870-0947, Japan. St-luke@oct-net.ne.jp
authors.forename: Takafumi
authors.initials: T
authors.lastname: Utsunomiya
authors.forename: Tae
authors.initials: T
authors.lastname: Naitou
authors.forename: Miyuki
authors.initials: M
authors.lastname: Nagaki
mesh_terms: D000328:Adult; D001755:Blastocyst / Q000502:physiology*; D003470:Culture Media; D046508:Culture Techniques / Q000379:methods*; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D015571:Follicular Fluid; D006801:Humans; D008875:Middle Aged; D011247:Pregnancy; D018873:Pregnancy Rate; D011446:Prospective Studies; D020554:Sperm Injections, Intracytoplasmic; D013997:Time Factors
chemical_list: D003470:Culture Media