title: The value of pronuclear scoring for the success of IVF and ICSI-cycles.
abstract: BACKGROUND
  Pronuclear scoring helps to identify good quality embryos already at the pronuclear stage. There are no data available, however, to demonstrate whether patients benefit from a higher pregnancy rate after pronuclear scoring.
  
  
  METHODS
  In a retrospective, matched cohort study 338 cycles in which patients chose to score their oocytes at the pronuclear stage (scoring group) were compared with 338 cycles without scoring (control group). The cycles were matched for maternal age, number of previous IVF and ICSI cycles, cryopreservation (yes/no) and diagnosis of primary infertility.
  
  
  RESULTS
  The pregnancy rate was not significantly different between the scoring group and the control group (24.0 vs. 21.0%, NS) in spite of more cycles with grade A embryos and a higher number of embryos transferred. The presence of a Z1 pronuclear oocyte was found to be associated with the retrieval of more oocytes, a higher fertilization rate and more grade A embryos, as well as a non-significant increase in pregnancy rates (25.1 vs. 18.8%).
  
  
  CONCLUSIONS
  Benefit from pronuclear scoring seems to be small. Apparently, experienced biologists are able to select "good-quality" pronuclear oocytes in the same way they would do after scoring. However, the results might be biased by differences between the groups.
authors.affiliation: Department of Gynecology and Obstetrics, University Clinic Schleswig-Holstein , Campus Lübeck, Ratzeburger Allee 160, 23538 Lubeck, Germany. A.K.Ludwig@web.de
authors.forename: A K
authors.initials: AK
authors.lastname: Ludwig
authors.forename: S
authors.initials: S
authors.lastname: Werner
authors.forename: K
authors.initials: K
authors.lastname: Diedrich
authors.forename: B
authors.initials: B
authors.lastname: Nitz
authors.forename: M
authors.initials: M
authors.lastname: Ludwig
mesh_terms: D000328:Adult; D048750:Cell Nucleus Division; D002470:Cell Survival; D015331:Cohort Studies; D005260:Female; D005306:Fertilization; D005307:Fertilization in Vitro; D006801:Humans; D008423:Maternal Age; D009865:Oocytes / Q000502:physiology*; D011237:Predictive Value of Tests; D011247:Pregnancy; D018873:Pregnancy Rate; D012189:Retrospective Studies