What Is the Trophectoderm?

The trophectoderm is the outer layer of cells in a blastocyst-stage embryo that will eventually develop into the placenta and other supporting tissues required for fetal development.

Clinical significance

During IVF, embryologists evaluate the trophectoderm as part of blastocyst grading and may biopsy these cells during preimplantation genetic testing.

Common confusion

Some people believe the trophectoderm becomes the fetus itself, but it actually forms extraembryonic structures such as the placenta.

Related reference

/glossary/blastocyst →/glossary/inner-cell-mass →/glossary/embryo-grading →/glossary/pgta →/glossary/embryo-culture →← Back to Glossary Index

Used in

Blastocyst →Inner Cell Mass →Embryo Grading →PGT-A →Embryo Culture →

This content defines terminology for educational orientation. It does not constitute medical advice.

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