Embryology
By day two an embryo typically has around four cells and by day three around eight. Transfer at this stage is still used in some situations, particularly where only one or two embryos are available and the laboratory judges that the body may be a better environment than extended culture.
Also known as: day 3 embryo, cleavage stage
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.