MORPHOMETRIC CHARACTERIZATION OF NORMAL AND ABNORMAL HUMAN ZYGOTES

Human zygotes (n = 278) from 96 in-vitro fertilization gonadotrophin-s timulated cycles were photographed in their pronuclear stage (16-18 h post-insemination). Normal morphological fertilization (two pronuclei) was observed in 215 zygotes, 17 showed only one pronucleus, 40 showed three pronuclei and six showed four, Area, perimeter and maximum and minimum diameters of each zygote and pronucleus were measured using an IBAS 2000 (Kontron) image analyser. When the four groups were compare d, whole zygotes did not show any morphometric difference, However, pr onuclei from these groups showed that a high number of pronuclei was d irectly related to small pronuclei. Differences in pronuclear size and a linear increase in the nucleus/cytoplasm relationship were found wh ich varied with the number of pronuclei.