title: Predicting aneuploidy in human oocytes: key factors which affect the meiotic process.
abstract: BACKGROUND
  To estimate the incidence of aneuploidy in relation to patients' characteristics, the type of hormonal stimulation and their response to induction of multiple follicular growth, 4163 first polar bodies (PB1s) were analyzed.
  
  
  METHODS
  Five hundred and forty four infertile couples underwent 706 assisted conception cycles (640 with poor prognosis indications and 66 controls) in which chromosomal analysis of PB1 for the chromosomes 13, 15, 16, 18, 21 and 22 was performed. Results were evaluated in a multivariate analysis.
  
  
  RESULTS
  The proportion of normal oocytes was directly correlated (P < 0.01) with (i) the number of mature oocytes and (ii) the establishment of a clinical pregnancy; and inversely correlated (P < 0.01) with (i) female age, (ii) causes of female infertility (endometriosis, abortions, ovulatory factor), (iii) poor prognosis indications (female age, number of previous cycles, multiple poor prognosis indications), (iv) number of FSH units per oocyte and (v) number of FSH units per metaphase II oocyte. There was a weak significance of frequency (P < 0.05) between type of abnormality (originated by chromatid predivision, chromosome non-disjunction or combined mechanisms in the same oocyte) and groups of the studied variables, rather than to a specific abnormality or a specific chromosome.
  
  
  CONCLUSIONS
  The type of infertility had a significant effect on errors derived from the first meiotic division, whose incidence was significantly higher in the presence of endometriosis or of an ovulatory factor, and in women that experienced repeated abortions. Each aneuploidy event was found to be dependent not on a specific variable, but on groups of variables. In addition, the tendency of chromosomal abnormalities to occur simultaneously implies that the deriving aneuploidies can be of any type.
authors.affiliation: S.I.S.Me.R., Reproductive Medicine Unit, Via Mazzini, 12, 40138 Bologna, Italy. luca.gianaroli@sismer.it
authors.forename: L
authors.initials: L
authors.lastname: Gianaroli
authors.forename: M C
authors.initials: MC
authors.lastname: Magli
authors.forename: G
authors.initials: G
authors.lastname: Cavallini
authors.forename: A
authors.initials: A
authors.lastname: Crippa
authors.forename: A
authors.initials: A
authors.lastname: Capoti
authors.forename: S
authors.initials: S
authors.lastname: Resta
authors.forename: F
authors.initials: F
authors.lastname: Robles
authors.forename: A P
authors.initials: AP
authors.lastname: Ferraretti
mesh_terms: D000328:Adult; D000782:Aneuploidy; D002869:Chromosome Aberrations; D025063:Chromosome Disorders / Q000150:complications / Q000453:epidemiology*; D020223:Chromosome Painting; D004715:Endometriosis / Q000150:complications; D005260:Female; D006801:Humans; D015994:Incidence; D007247:Infertility, Female / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology*; D008423:Maternal Age; D008540:Meiosis; D009865:Oocytes / Q000737:chemistry*; D010062:Ovulation Induction / Q000009:adverse effects; D011247:Pregnancy; D011256:Pregnancy Outcome; D011379:Prognosis; D017584:Reproductive History; D012307:Risk Factors; D020554:Sperm Injections, Intracytoplasmic