title: The relationship of pronuclear stage morphology and chromosome status at cleavage stage.
abstract: OBJECTIVE
  Infertile couples undergoing in vitro fertilization-embryo transfer (IVF-ET) program were included to study the relationship of pronuclear stage morphology and chromosome status at cleavage stage.
  
  
  METHODS
  Eighteen to twenty-one hours after fertilization, zygotes were checked for pronuclear morphology with modified Scott Z-score system. After embryo transfer on day 3, arrested or non-transferred 2 PN embryos were spread for fluorescence in situ hybridization (FISH) staining of probes to chromosomes 18, X and Y.
  
  
  RESULTS
  Ninety-eight embryos were successfully fixed and stained. The chromosome status were recorded in each 2 PN score group: 7 (54%) of 13 embryos in Z2 group, 14 (35%) of 40 in Z3 group and 10 (36%) of 28 in Z4 group being normal diploid. Z1 group has 12 (71%) of 17 embryos being normal diploid, which is significantly more than Z3 (p = 0.020) and Z4 group (p = 0.033).
  
  
  CONCLUSIONS
  Our results demonstrated a high probability to get normal diploid embryos if good morphology at pronuclear stage was used as selection criteria, especially for Z1 score embryos.
authors.affiliation: Department of Obstetrics and Gynecology, Lin-Kou Medical Center, Chang Gung Memorial Hospital and Medical College, 5, Fu-Hsing Street, Kwei-Shan, Tao-Yuan 333, Taiwan. ckchen@cgmh.org.tw
authors.forename: Chun-Kai
authors.initials: CK
authors.lastname: Chen
authors.forename: Guan-Yi
authors.initials: GY
authors.lastname: Shen
authors.forename: Shang-Gwo
authors.initials: SG
authors.lastname: Horng
authors.forename: Chia-Woei
authors.initials: CW
authors.lastname: Wang
authors.forename: Hong-Yuan
authors.initials: HY
authors.lastname: Huang
authors.forename: Hsin-Shin
authors.initials: HS
authors.lastname: Wang
authors.forename: Yung-Kuei
authors.initials: YK
authors.lastname: Soong
mesh_terms: D001757:Blastomeres / Q000166:cytology / Q000502:physiology; D002877:Chromosomes, Human; D041321:Chromosomes, Human, X; D041322:Chromosomes, Human, Y; D004171:Diploidy; D010064:Embryo Implantation; D004624:Embryo Transfer; D005314:Embryonic and Fetal Development / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008297:Male; D009865:Oocytes / Q000166:cytology* / Q000502:physiology; D010062:Ovulation Induction; D018579:Patient Selection; D011247:Pregnancy; D011336:Probability; D015053:Zygote / Q000648:ultrastructure