title: Influence of oocytes and spermatozoa on early embryonic development.
abstract: OBJECTIVE
  To evaluate the effect of oocytes and spermatozoa on early embryonic development.
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  Infertility Clinic, the Family Federation of Finland.
  
  
  METHODS
  Fifty-nine oocyte donation cycles with oocytes shared among 118 recipient couples.
  
  
  METHODS
  Culture of all fertilized oocytes.
  
  
  METHODS
  Standard sperm (concentration, progressive motility, and morphology according to Tygerberg strict criteria) and embryo (morphology and cleavage stage) characteristics.
  
  
  RESULTS
  A marked effect of the oocyte on both embryo morphology and blastomere cleavage rate was demonstrated. In addition, a significant sperm effect on blastomere cleavage rate was found. Sperm morphology as determined according to strict criteria rather than sperm count or progressive motility was positively associated with the blastomere cleavage rate. None of the measured sperm characteristics influenced embryo morphology.
  
  
  CONCLUSIONS
  Embryo morphology, i.e., fragmentation and blastomere uniformity, are predominantly determined by oocyte quality, whereas both the oocyte and spermatozoa influence the blastomere cleavage rate.
authors.affiliation: Infertility Clinic, The Family Federation of Finland, Helsinki, Finland. salumets@vaestolitto.fi
authors.forename: Andres
authors.initials: A
authors.lastname: Salumets
authors.forename: Anne Maria
authors.initials: AM
authors.lastname: Suikkari
authors.forename: Tonu
authors.initials: T
authors.lastname: Möls
authors.forename: Viveca
authors.initials: V
authors.lastname: Söderström-Anttila
authors.forename: Timo
authors.initials: T
authors.lastname: Tuuri
mesh_terms: D000328:Adult; D001757:Blastomeres / Q000166:cytology; D002970:Cleavage Stage, Ovum; D046508:Culture Techniques; D004622:Embryo, Mammalian / Q000166:cytology; D005314:Embryonic and Fetal Development / Q000502:physiology*; D005260:Female; D005865:Gestational Age; D006801:Humans; D008297:Male; D008875:Middle Aged; D009865:Oocytes / Q000502:physiology*; D012189:Retrospective Studies; D013094:Spermatozoa / Q000166:cytology / Q000502:physiology*