title: Evidence of a high proportion of premature unbalanced separation of sister chromatids in the first polar bodies of women of advanced age.
abstract: BACKGROUND
  Maternal ageing is the only aetiological factor unequivocally linked to aneuploidy. Two mechanisms seem to explain these abnormalities in oocytes: non-disjunction and premature unbalanced separation of sister chromatids (PSSC). Previous studies of unfertilized oocytes argue for a major role of PSSC in the aetiology of aneuploidy for women of advanced age, but in vitro ageing of the oocytes could influence the results.
  
  
  METHODS
  Owing to the high prevalence of aneuploidy in women of advanced age, chromosomal screening of the first polar body just before ICSI was offered to women (from 38 years of age) included in an assisted reproduction programme.
  
  
  RESULTS
  Among 141 oocytes from 29 women (mean age 40 years and 2 months), 43 (30.5%) were abnormal. Sixty-five abnormalities were found and PSSC was involved in 80% of cases.
  
  
  CONCLUSIONS
  These results are in accordance with previous studies and confirm, in 'fresh' oocytes, the major role of PSSC in the aetiology of aneuploidy in women of advanced age.
authors.affiliation: Department of reproductive biology, cytogenetics, gynaecology and obstetrics, CHI Poissy-Saint Germain, Poissy, France. fvialard@hotmail.com
authors.forename: F
authors.initials: F
authors.lastname: Vialard
authors.forename: C
authors.initials: C
authors.lastname: Petit
authors.forename: M
authors.initials: M
authors.lastname: Bergere
authors.forename: D Molina
authors.initials: DM
authors.lastname: Gomes
authors.forename: V
authors.initials: V
authors.lastname: Martel-Petit
authors.forename: R
authors.initials: R
authors.lastname: Lombroso
authors.forename: Y
authors.initials: Y
authors.lastname: Ville
authors.forename: H
authors.initials: H
authors.lastname: Gerard
authors.forename: J
authors.initials: J
authors.lastname: Selva
mesh_terms: D000328:Adult; D000375:Aging; D000782:Aneuploidy; D002842:Chromatids / Q000235:genetics*; D020090:Chromosome Segregation; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D009865:Oocytes / Q000166:cytology; D019836:Preimplantation Diagnosis; D020554:Sperm Injections, Intracytoplasmic