Morphometric categorization of the human oocyte and early conceptus

Hum Reprod. 1990 Jul;5(5):613-8. doi: 10.1093/oxfordjournals.humrep.a137155.

Abstract

Morphometrical procedures were used to quantitatively evaluate human oocytes and embryos in an IVF programme. The metaphase II oocyte was an irregular 3.5 x 10(6) microns 3 sphere of 1.05 coefficient of form. The ooplasmic volume of 1.4 x 10(6) microns 3 was reduced by 10% by fertilization. The zona pellucida behaved as a stable and almost spherical envelope of 1.8 x 10(6) microns 3 volume and 17 microns thickness. Through the first three cleavages, mean blastomere reduces 28.5% volume per division, evolving from an irregular spherical shape with 0.9 coefficient of form to an ellipsoid (0.8) at the 8-cell stage. The coefficient of diversity between sister blastomeres progressively moved from 1.4 to 1.6 during the first two (2n) cleavages. The coefficient of diversity also increased at 3-cell (2.2) and 6-cell (2.6) asynchronous divisions. Morphologically abnormal embryos showed some morphometrical differences. Embryos which successfully implanted and progressed to birth showed a higher coefficient of diversity between sister blastomeres.

MeSH terms

  • Blastomeres / ultrastructure*
  • Cell Nucleus / ultrastructure
  • Cleavage Stage, Ovum / ultrastructure*
  • Cytoplasm / ultrastructure
  • Female
  • Fertilization in Vitro*
  • Humans
  • Oocytes / ultrastructure*
  • Vitelline Membrane / ultrastructure
  • Zona Pellucida / ultrastructure