title: Pronuclear morphology evaluation with subsequent evaluation of embryo morphology significantly increases implantation rates.
abstract: OBJECTIVE
  To elucidate the relative predictive value of implantation markers at different stages of preimplantation development.
  
  
  METHODS
  Correlation of pronuclear morphology with embryo morphology and implantation rates in retrospective and prospective analysis of in vitro fertilization/intracytoplasmic sperm injection (IVF-ICSI) treatment cycles.
  
  
  METHODS
  Private infertility center.
  
  
  METHODS
  A total of 441 couples undergoing infertility treatment.
  
  
  METHODS
  None.
  
  
  METHODS
  Size of pronuclei and distance between them, the number and polarization of nucleolus precursor bodies (NPB) at the one-cell stage, embryo cleavage and fragmentation rates on days 2 and 3, and pregnancy and implantation rates.
  
  
  RESULTS
  Polarization of the NPB in both pronuclei had a statistically significant correlation with normal membrane breakage during ICSI (40%, compared with 33% easy, and 31% difficult membrane breakage) and also with faster cleavage and lower fragmentation rates of embryos. Sixty-one percent of implanting embryos had polarization of the NPB in both pronuclei compared with 37% for all embryos. Larger distance between pronuclei and their unequal size had a statistically significant correlation with slower cleavage and inferior embryo quality. Embryo selection based on only pronuclear morphology or on only day-3 embryo morphology yielded implantation rates of 15.1% and 12.1%, respectively. Embryo selection based on sequential evaluation of both pronuclear morphology and embryo morphology on day 3 resulted in a 21.1% implantation rate.
  
  
  CONCLUSIONS
  Polarization of NPB in both pronuclei is as reliable marker of implantation as embryo morphology on day 3. However, pronuclear morphology assessment improves embryo selection only when it is combined with embryo morphology evaluation on day 3.
authors.affiliation: Clinica e Centro de Pesquisa em Reproducao Humana Dr. Roger Abdelmassih, São Paulo, Brazil. nagy.zsolt.peter@iol.it
authors.forename: Zsolt P
authors.initials: ZP
authors.lastname: Nagy
authors.forename: Dmitri
authors.initials: D
authors.lastname: Dozortsev
authors.forename: Michael
authors.initials: M
authors.lastname: Diamond
authors.forename: Laura
authors.initials: L
authors.lastname: Rienzi
authors.forename: Filippo
authors.initials: F
authors.lastname: Ubaldi
authors.forename: Roger
authors.initials: R
authors.lastname: Abdelmassih
authors.forename: Ermanno
authors.initials: E
authors.lastname: Greco
mesh_terms: D000328:Adult; D002466:Cell Nucleolus / Q000648:ultrastructure; D002970:Cleavage Stage, Ovum / Q000502:physiology*; D010064:Embryo Implantation / Q000502:physiology*; D004624:Embryo Transfer; D005260:Female; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D011247:Pregnancy; D011446:Prospective Studies; D012189:Retrospective Studies; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods*; D018709:Statistics, Nonparametric