title: First meiosis errors in immature oocytes generated by stimulated cycles.
abstract: OBJECTIVE
  To investigate chromosomal errors detected by first polar body (PB) biopsy in relation to the nuclear maturity of the oocytes.
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  Reproductive medicine unit.
  
  
  METHODS
  Eighty-seven cycles were examined by PB biopsy for aneuploidy. Indications were maternal age >or=38 years (49 cycles), repeated IVF failures (22 cycles), and others (16 cycles).
  
  
  METHODS
  First polar bodies were analyzed for the chromosomes 13, 16, 18, 21, and 22 in both in vivo and in vitro matured oocytes. Euploid oocytes were inseminated by intracytoplasmic sperm injection.
  
  
  METHODS
  Chromosomal status of the analyzed oocytes, development after intracytoplasmic sperm injection, pregnancy, and implantation rates.
  
  
  RESULTS
  In in vitro matured oocytes, the proportion of chromosomal abnormalities was higher than in in vivo matured oocytes (70% vs. 54%, P<.005), with complex abnormalities being the prevailing defect (62% vs. 40%, P<.001). Conversely, the presence of an extra chromatid or the lack of a chromatid was more frequent in in vivo than in in vitro matured oocytes (55% vs. 34%, P<.001).
  
  
  CONCLUSIONS
  The low viability of in vitro matured oocytes from stimulated cycles could be related to a significantly higher proportion of chromosomal abnormalities compared with in vivo matured oocytes. Complex abnormalities, involving two or more chromosomes, gave the strongest contribution to the detected increase.
authors.affiliation: Reproductive Medicine Unit, Italian Society for the Study of Reproductive Medicine, Bologna, Italy.
authors.forename: M Cristina
authors.initials: MC
authors.lastname: Magli
authors.forename: Anna P
authors.initials: AP
authors.lastname: Ferraretti
authors.forename: Andor
authors.initials: A
authors.lastname: Crippa
authors.forename: Michela
authors.initials: M
authors.lastname: Lappi
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Feliciani
authors.forename: Luca
authors.initials: L
authors.lastname: Gianaroli
mesh_terms: D000328:Adult; D002470:Cell Survival; D002869:Chromosome Aberrations; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007247:Infertility, Female / Q000235:genetics / Q000473:pathology* / Q000628:therapy; D008540:Meiosis; D008597:Menstrual Cycle; D009865:Oocytes / Q000254:growth & development* / Q000473:pathology*; D010062:Ovulation Induction; D011247:Pregnancy; D011256:Pregnancy Outcome