Eggs, sperm & embryos
The trophectoderm is the layer of cells surrounding the blastocyst cavity, which develops into the placenta and supporting membranes. It is also the layer sampled in an embryo biopsy for preimplantation genetic testing, because taking cells from here avoids removing cells destined to form the fetus.
Also known as: TE, trophoblast layer
Related South Africa guides
Sources
- ESHRE/ICMART glossary and ESHRE laboratory guidance
Last reviewed: 8 September 2026. Written by the Antega Editorial Team. General information only — always follow the advice of your own clinic, doctor or pharmacist.