Total cytoplasmic volume as biomarker of fragmentation in human embryos

To use computer-controlled, multilevel embryo morphology analysis to quantify the reduction in cytoplasmic volume from the zygote stage to the combined volume of the individual blastomeres as an expression for the degree of fragmentation.

Zygotes and their corresponding embryos from patients referred to ICSI treatment were analyzed. Sequences of digital images were taken focussing at 5-microm intervals through the zygotes and embryos. Assessment of cytoplasmic volumes and fragmentation were based on these sequences.

The mean cytoplasmic reduction of the embryos were significant linear increasing with increasing degree of fragmentation assessed by traditional evaluation (P < 0.001). Embryos scored to be highly fragmented had on average a cytoplasmic reduction of 63% larger than embryos assessed to have no fragmentation. In total, 68% of the embryos had a cytoplasmic reduction lying within their allocated fragmentation group.

Assessment of embryonic fragmentation based on computer-controlled, multi-level embryo analysis of the blastomere volumes expressed in relation to the volume of the preceding zygote may allow a more precise and standardized evaluation of fragmentation than the traditional fragmentation assessment.