Early pronuclear breakdown is a good indicator of embryo quality and viability

Peter Fancsovits, Laszlone Toth, Zoltan F. Takacs, Akos Murber, Zoltan Papp, Janos Urbancsek

Research output: Contribution to journalArticle

29 Citations (Scopus)


Objective: To examine whether the timing of pronuclear breakdown can be a predictor of embryo quality and viability. Design: Retrospective comparison of the development and quality of early and late developing zygotes. Setting: Infertility and endocrinology unit in a university hospital. Patient(s): One thousand seven hundred eighty-two zygotes obtained in 383 consecutive IVF cycles. Intervention(s): Culture of all fertilized embryos. Main Outcome Measure(s): Number of fertilized zygotes showing early pronuclear breakdown at 22-25 hours postinsemination, embryo quality, pregnancy rates (PR), implantation rates. Result(s): Early pronuclear breakdown embryos had a significantly higher cell number (4.4 ± 1.2) compared with the late pronuclear breakdown embryos (3.6 ± 1.4). When comparing the frequency of the early pronuclear breakdown embryos according to the method of fertilization, we failed to find any significant difference between the IVF (37.1%) and the intracytoplasmic sperm injection (ICSI) (41.1%) groups. The transfer of early pronuclear breakdown embryos resulted in a significantly higher clinical pregnancy rate than those with late pronuclear breakdown (48.3% vs. 27.3%). The implantation rate was higher in the early pronuclear breakdown group than in the late pronuclear breakdown group (26.5% vs. 15.1%). Conclusion(s): Early pronuclear breakdown is a strong indicator of embryo viability, and may be used as an additional criterion in the selection of embryos for transfer.

Original languageEnglish
Pages (from-to)881-887
Number of pages7
JournalFertility and Sterility
Issue number4
Publication statusPublished - Oct 1 2005


  • Early cleavage
  • Early pronuclear breakdown
  • Embryo quality
  • Implantation rate
  • Pregnancy rates

ASJC Scopus subject areas

  • Reproductive Medicine
  • Obstetrics and Gynaecology

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