Embryo fragmentation refers to small fragments of cellular material that can appear alongside the main cells of a developing embryo, particularly at the cleavage stage. Embryologists record the extent of fragmentation as part of describing an embryo's appearance, usually as a rough proportion of the embryo's volume. Multinucleation describes a related appearance, in which one cell of an early embryo seems to contain more than one nucleus rather than the usual single nucleus. Some degree of fragmentation, and occasional multinucleation, are common and do not mean an embryo cannot develop further or cannot result in a pregnancy; they are appearance-based observations used alongside cell number and other features when embryos are graded.
Also known as: fragmented embryo, multinucleated blastomere, multinucleation
Sources
- ICMR Standard Treatment Workflows (icmr.gov.in/standard-treatment-workflows-stws)
- European Society of Human Reproduction and Embryology (eshre.eu)
Last reviewed: 9 September 2026. Written by the Antega Editorial Team. General information only — always follow the advice of your own clinic, doctor or pharmacist.