Developmental prognosis for zygotes based on pronuclear pattern: usefulness of pronuclear scoring.
OBJECTIVE
To relate pronuclear patterns (PN) and zygote cytoplasmic appearance and embryo morphology.


METHODS
The usefulness of PN classification described by Tesarik et al. 1999 (patterns p0-5) and Scott et al. 2000 (Z1-4), for embryo selection is assessed.


RESULTS
Sinchrony on polarization and number of nucleolar precursor bodies (NPB) were associated with good quality embryos (p0 60.9% and p3 67.3%, and Z1 62.5% and Z2 64.7%; p<0.01). Pattern 4 zygotes were associated with small number of NPB developed into multinucleated embryos (14.3%) and poor quality embryos (61.9%). No significant differences were found in the pregnancy rate between transfer of at least one good prognosis PN pattern and transfer of poor prognosis PN patterns, although 75% of the transfers included at least one embryo derived from a pattern 0 zygote, and 55% included embryos from categories Z1 or Z2.


CONCLUSIONS
Sequential assessment involving the evaluation of oocyte quality, the classification of PN patterns and embryo morphology allows a more accurate evaluation of embryos to be selected for transfer.
Arroyo
Gemma
G
Servei Medecina de la Reproducció, Dpt Obstetrícia i Ginecologia, Institut Universitari Dexeus, Passeig Bonanova, Barcelona, Spain. gemarr@dexeus.com
Veiga
Anna
A
Santaló
Josep
J
Barri
Pere Nolasc
PN
D002467:Cell Nucleus / Q000502:physiology*; D016764:Cell Polarity; D003593:Cytoplasm / Q000648:ultrastructure; D019924:Embryo Disposition; D005260:Female; D006801:Humans; D010062:Ovulation Induction; D011247:Pregnancy; D011379:Prognosis; D014617:Vacuoles / Q000648:ultrastructure; D015053:Zygote / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure