Embryology
The trophectoderm surrounds the fluid cavity of a blastocyst and goes on to form the placenta. It is the layer sampled in a trophectoderm biopsy for PGT, because taking cells from it avoids removing cells destined to become the fetus.
Also known as: TE, outer cell layer
Sources
- European Society of Human Reproduction and Embryology (eshre.eu)
- Royal Australian and New Zealand College of Obstetricians and Gynaecologists (ranzcog.edu.au)
Last reviewed: 10 September 2026. Written by the Antega Editorial Team. General information only — always follow the advice of your own clinic, doctor or pharmacist.