title: The cytogenetic constitution of embryos derived from immature (metaphase I) oocytes obtained after ovarian hyperstimulation.
abstract: OBJECTIVE
  To examine the chromosomal content of embryos resulting from metaphase I (MI) oocytes obtained after ovarian hyperstimulation for IVF.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  University-based IVF Center, Assaf Harofeh Medical Center, Tel Aviv University, Israel.
  
  
  METHODS
  One hundred fifty women undergoing assisted reproduction technique (ART).
  
  
  METHODS
  Intracytoplasmic sperm injection (ICSI) was performed in MI oocytes that were retrieved after ovarian stimulation. A portion of these oocytes extruded their polar body (rescued in vitro-matured metaphase II [IVM-MII]) after different incubation periods and the remainder did not (arrested MI oocytes). Fluorescence in situ hybridization was performed using probes for chromosomes X, Y, 18.
  
  
  METHODS
  Fertilization rate, number of blastomeres, and embryo euploidy.
  
  
  RESULTS
  Embryos from rescued IVM-MII oocytes showed significantly higher fertilization rates and more blastomeres per embryo compared with those from arrested MI oocytes (58.5% vs. 43.9% and 5.7 vs. 5.0, respectively). The chromosomal analysis of these embryos revealed a high rate of aberrations (80.6%), mainly complex mosaics. This rate was elevated in embryos from arrested IVM oocytes (97.2%), and after longer incubation periods. No chromosomally normal embryos were found after 24 hours of incubation of their corresponding oocytes.
  
  
  CONCLUSIONS
  Embryos originating from MI oocytes have a high rate of chromosomal aneuploidy, and their replacement should be reconsidered.
authors.affiliation: Infertility and IVF Unit, Assaf Harofeh Medical Center, Zerifin, Israel. embriology@asaf.health.gov.il
authors.forename: Deborah
authors.initials: D
authors.lastname: Strassburger
authors.forename: Alexandra
authors.initials: A
authors.lastname: Goldstein
authors.forename: Shevach
authors.initials: S
authors.lastname: Friedler
authors.forename: Aryeh
authors.initials: A
authors.lastname: Raziel
authors.forename: Esti
authors.initials: E
authors.lastname: Kasterstein
authors.forename: Maya
authors.initials: M
authors.lastname: Mashevich
authors.forename: Mory
authors.initials: M
authors.lastname: Schachter
authors.forename: Raphael
authors.initials: R
authors.lastname: Ron-El
authors.forename: Orit
authors.initials: O
authors.lastname: Reish
mesh_terms: D000782:Aneuploidy; D002478:Cells, Cultured; D002869:Chromosome Aberrations / Q000196:embryology / Q000706:statistics & numerical data; D002970:Cleavage Stage, Ovum / Q000166:cytology / Q000502:physiology; D020732:Cytogenetic Analysis; D004622:Embryo, Mammalian / Q000166:cytology* / Q000378:metabolism*; D005260:Female; D005306:Fertilization / Q000502:physiology; D006801:Humans; D008297:Male; D008677:Metaphase / Q000235:genetics / Q000502:physiology; D054315:Oocyte Retrieval / Q000379:methods; D009865:Oocytes / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D009866:Oogenesis / Q000235:genetics; D010062:Ovulation Induction; D020554:Sperm Injections, Intracytoplasmic; D013997:Time Factors