title: Low blastocyst formation rates in day-2 fertilized oocytes.
abstract: OBJECTIVE
  To examine the blastocyst formation rates of day-2 fertilized oocytes.
  
  
  METHODS
  A retrospective study of the outcomes/blastocyst formation of day-2 fertilized oocytes was undertaken.
  
  
  RESULTS
  Fertilization rates of day-1 and -2 oocytes by intra-cytoplasmic sperm injection were similar. The development frequencies to four cells were similar. However, the blastulation rates were significantly lower from the day-2 fertilized eggs. The fertilization rates from day-2 conventional in vitro fertilization reinsemination were lower than the fertilization rates of day-1 oocytes. The blastulation rates from day-2 fertilized eggs were also lower than the rates from day-1 fertilized eggs in the in vitro fertilization group.
  
  
  CONCLUSIONS
  Fertilization is not a good indicator to predict the viability of fertilized oocytes. Day-2 fertilized oocytes had significantly lower blastocyst formation rates than the rates from day-1 fertilized oocytes.
authors.affiliation: Obstetrical and Gynecological Associates, Houston, Texas 77504-1989, USA.
authors.forename: J
authors.initials: J
authors.lastname: Gullett
authors.forename: G M
authors.initials: GM
authors.lastname: Grunert
authors.forename: C T
authors.initials: CT
authors.lastname: Valdes
authors.forename: R C
authors.initials: RC
authors.lastname: Dunn
authors.forename: W S
authors.initials: WS
authors.lastname: Wun
mesh_terms: D000328:Adult; D001755:Blastocyst; D004624:Embryo Transfer; D005314:Embryonic and Fetal Development; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D008845:Microinjections; D018873:Pregnancy Rate; D012099:Reproductive Techniques; D012189:Retrospective Studies; D013997:Time Factors; D015053:Zygote / Q000166:cytology*