title: Evidence for maternal predisposition to chromosome aneuploidy in multiple oocytes of some in vitro fertilization patients.
abstract: OBJECTIVE
  To assess the rate of chromosome aneuploidy (e.g., extra or missing chromosomes) in oocytes remaining unfertilized in our in vitro fertilization (IVF) program. To determine whether two parameters of the IVF technique, advanced maternal age and hormonal follicle stimulation, affect this rate.
  
  
  METHODS
  Data on oocyte retrieval, fertilization, and aneuploidy rates are analyzed to test for possible relations with maternal age and two hormonal stimulation regimens.
  
  
  METHODS
  Patients of our IVF program from 119 stimulated cycles over 8 months.
  
  
  METHODS
  In vitro fertilization patients selected for having oocytes (1 to 18) remaining unfertilized after insemination in vitro.
  
  
  RESULTS
  Advanced maternal age decreases both the number of retrieved oocytes and the fertilization rate, but hormonal treatments have no effect. Aneuploidy (rate 27%), involving group G most frequently, appears associated with advanced age. Patients who were previously parous produced significantly reduced numbers of aneuploid oocytes compared with the nonparous group. A significant excess (P = 0.01) of patients had multiple oocytes all alike (all haploid or all aneuploid), showing correlation among multiple oocytes of a patient in chromosome status.
  
  
  CONCLUSIONS
  Maternal age affects reproductive performance and is related to specific chromosomal aneuploidy. Women who were previously parous are more likely to produce normal oocytes than nonparous women; oocyte normality therefore may improve the chance for a future successive pregnancy. Nonrandomness in chromosome abnormality of some patients' multiple oocytes is evidence for maternal predisposition to meiotic nondisjunction. Consequently, these patients are at risk for failed IVF cycles.
authors.affiliation: Department of Obstetrics and Gynaecology, University of Toronto, Ontario, Canada.
authors.forename: M T
authors.initials: MT
authors.lastname: Zenzes
authors.forename: P
authors.initials: P
authors.lastname: Wang
authors.forename: R F
authors.initials: RF
authors.lastname: Casper
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000782:Aneuploidy; D002478:Cells, Cultured; D002877:Chromosomes, Human / Q000648:ultrastructure*; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007621:Karyotyping; D008423:Maternal Age; D009865:Oocytes / Q000166:cytology* / Q000502:physiology; D012044:Regression Analysis; D016896:Treatment Outcome