title: [Clinical application of a modified pronuclear stage scoring system following conventional in-vitro fertilization].
abstract: OBJECTIVE
  To assess the clinical value of pronuclear stage scoring system in human conventional in vitro fertilization-embryo transfer (IVF-ET) program.
  
  
  METHODS
  A modified pronuclear scoring system was used to score zygotes 16 - 18 hours after insemination during conventional IVF.
  
  
  RESULTS
  A total of 178 IVF cycles were recruited in this study. Cycles with mean pronuclear score (sum of pronuclear scores of all transferred embryos divided by total number of transferred embryos) > or = 13 had significant high pregnancy and implantation rate, as compared to those with less than 13 (49.1% and 26.5% Vs 29.4% and 15.0% respectively). Although the pregnancy, implantation rate and multiple pregnancy rate tend to increase with the increasing number of zygotes with full pronuclear score (= 15) among transferred embryos, no significant difference could be found (P > 0.05). When all embryos were analyzed, 77.2% zygotes with pronuclear score > or = 11 could be transferred or cryopreserved, while those with pronuclear score less than 11 decreased to 46.1%.
  
  
  CONCLUSIONS
  Pronuclear stage scoring system provides additional parameter for embryo selection. However, pronuclear morphology could only partly represent embryonic viability. Combination with the scoring of both pronuclear stage and cleavage stage embryos for selecting transferred embryos is indispensable.
authors.affiliation: Reproductive Medical Research Center, the First Affiliated Hospital of Sun Yan-sen University, Guangzhou 510080, China.
authors.forename: Yan-wen
authors.initials: YW
authors.lastname: Xu
authors.forename: Guang-lun
authors.initials: GL
authors.lastname: Zhuang
authors.forename: Cong
authors.initials: C
authors.lastname: Fang
authors.forename: Yi-min
authors.initials: YM
authors.lastname: Shu
authors.forename: Min-fang
authors.initials: MF
authors.lastname: Zhang
authors.forename: Wen-lin
authors.initials: WL
authors.lastname: Peng
mesh_terms: D000328:Adult; D002970:Cleavage Stage, Ovum; D010064:Embryo Implantation; D004624:Embryo Transfer; D004622:Embryo, Mammalian / Q000648:ultrastructure; D005307:Fertilization in Vitro; D006801:Humans; D011237:Predictive Value of Tests; D015053:Zygote / Q000648:ultrastructure