Early pronuclear breakdown is a good indicator of embryo quality and viability.
OBJECTIVE
To examine whether the timing of pronuclear breakdown can be a predictor of embryo quality and viability.


METHODS
Retrospective comparison of the development and quality of early and late developing zygotes.


METHODS
Infertility and endocrinology unit in a university hospital.


METHODS
One thousand seven hundred eighty-two zygotes obtained in 383 consecutive IVF cycles.


METHODS
Culture of all fertilized embryos.


METHODS
Number of fertilized zygotes showing early pronuclear breakdown at 22-25 hours postinsemination, embryo quality, pregnancy rates (PR), implantation rates.


RESULTS
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%).


CONCLUSIONS
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.
Fancsovits
Peter
P
First Department of Obstetrics and Gynaecology, Semmelweis University School of Medicine, Budapest, Hungary. fancsi@noi1.sote.hu
Toth
Laszlone
L
Takacs
Zoltan F
ZF
Murber
Akos
A
Papp
Zoltan
Z
Urbancsek
Janos
J
D000328:Adult; D002467:Cell Nucleus / Q000502:physiology; D002470:Cell Survival / Q000502:physiology; D004624:Embryo Transfer; D004622:Embryo, Mammalian / Q000166:cytology / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D011247:Pregnancy; D018873:Pregnancy Rate; D012189:Retrospective Studies; D013997:Time Factors; D015053:Zygote / Q000166:cytology / Q000254:growth & development*