Glossary · Definition · v2026.3
What Is a Chromosomal Abnormality?
A chromosomal abnormality is any deviation from the normal number or structure of chromosomes. In IVF, chromosomal abnormalities in embryos are the leading cause of implantation failure, miscarriage, and failed transfers.
Clinical significance
Chromosomal abnormalities include whole-chromosome aneuploidy (extra or missing chromosomes), segmental aneuploidy (partial gains or losses), and structural rearrangements (translocations, inversions). PGT-A and PGT-SR are the primary methods for detecting these in embryos before transfer.
Common confusion
Not all chromosomal abnormalities cause the same outcomes. Some are lethal and prevent implantation entirely, while others (such as trisomy 21) are compatible with life but associated with developmental differences.
Related reference
Used in
This content defines terminology for educational orientation. It does not constitute medical advice.
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