title: Birth weight and sex ratio after transfer at the blastocyst stage in humans.
abstract: OBJECTIVE
  To analyze the birth weights and sex ratio of infants born after blastocyst transfer.
  
  
  METHODS
  Retrospective analysis.
  
  
  METHODS
  Three infertility clinics.
  
  
  METHODS
  Patients admitted for IVF with blastocyst transfer.
  
  
  METHODS
  None.
  
  
  METHODS
  Birth weights and sex ratio of infants born after blastocyst transfer.
  
  
  RESULTS
  Statistically significantly more male infants were born after transfer of fresh blastocysts, either cocultured or cultured in sequential media. No specific differences in birth weight were observed between infants born after blastocyst transfer and those born after spontaneous conception.
  
  
  CONCLUSIONS
  More male infants than female infants were born after blastocyst transfer when transfers were performed as soon as the blastocyst stage was reached and male embryos had a faster cleavage rate.
authors.affiliation: Institut Rhonalpin, Fondation Marcel Mérieux, Bron, France.
authors.forename: Y J
authors.initials: YJ
authors.lastname: Ménézo
authors.forename: J
authors.initials: J
authors.lastname: Chouteau
authors.forename: J
authors.initials: J
authors.lastname: Torelló
authors.forename: A
authors.initials: A
authors.lastname: Girard
authors.forename: A
authors.initials: A
authors.lastname: Veiga
mesh_terms: D001724:Birth Weight; D001755:Blastocyst; D018920:Coculture Techniques; D003470:Culture Media; D004624:Embryo Transfer / Q000379:methods; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D011272:Pregnancy, Multiple / Q000706:statistics & numerical data; D012744:Sex Ratio
chemical_list: D003470:Culture Media