title: Analysis of pronuclear zygote configurations in 459 clinical pregnancies obtained with assisted reproductive technique procedures.
abstract: BACKGROUND
  Embryos selection is crucial to maintain high performance in terms of pregnancy rate, reducing the risk of multiple pregnancy during IVF. Pronuclear and nucleolar characteristics have been proposed as an indicator of embryo development and chromosomal complement in humans, providing information about embryo viability.
  
  
  METHODS
  To correlate the zygote-score with the maternal age and the outcome of pregnancy, we analyzed the pronuclear and nucleolar morphology, the polar body alignment and the zygote configuration in 459 clinical pregnancies obtained by IVF and ICSI in our public clinic in Reggio Emilia, Italy. We derived odds ratios (OR) and Corenfield's 95% confidence intervals (CI). Continuous variables were compared with Student's t-test; P lower than .05 was considered statistically significant.
  
  
  RESULTS
  We observed a significant increase of "A" pronuclear morphology configuration in 38-41 years old patients in comparison to that lower than or equal to 32 years old and a significant decrease of "B" configuration in 38-41 years old patients in comparison to that lower than or equal to 32 and in comparison to that of 33-37 years old. Related to maternal age we found no significant differences in P1 and in P2 configuration. We found no correlation between zygote-score, embryo cleavage and embryo quality.
  
  
  CONCLUSIONS
  Our results confirm the limited clinical significance of zygote-score suggesting that it can not be associated with maternal age, embryo cleavage and embryo quality. The evaluation of embryo quality based on morphological parameters is probably more predictive than zygote-score.
authors.affiliation: Sterility Centre P. Bertocchi, Department of Obstetrics and Gynecology, Arcispedale Santa Maria Nuova, Reggio Emilia, Italy. nicoli.alessia@asmn.re.it
authors.forename: Alessia
authors.initials: A
authors.lastname: Nicoli
authors.forename: Francesco
authors.initials: F
authors.lastname: Capodanno
authors.forename: Lucia
authors.initials: L
authors.lastname: Moscato
authors.forename: Ilaria
authors.initials: I
authors.lastname: Rondini
authors.forename: Maria T
authors.initials: MT
authors.lastname: Villani
authors.forename: Antonella
authors.initials: A
authors.lastname: Tuzio
authors.forename: Giovanni B
authors.initials: GB
authors.lastname: La Sala
mesh_terms: D000328:Adult; D002970:Cleavage Stage, Ovum / Q000166:cytology; D005260:Female; D006801:Humans; D008297:Male; D008423:Maternal Age; D008954:Models, Biological; D011247:Pregnancy; D018873:Pregnancy Rate; D011272:Pregnancy, Multiple / Q000706:statistics & numerical data; D027724:Reproductive Techniques, Assisted / Q000706:statistics & numerical data; D015053:Zygote / Q000166:cytology*; D017388:Zygote Intrafallopian Transfer / Q000379:methods