Embryo culture

Embryo culture is the period during which embryos are kept in specialised laboratory incubators, in fluid designed to support their development, between fertilisation and the point of transfer or freezing. Extended embryo culture refers to keeping embryos in culture through to the blastocyst stage, on Day 5 or Day 6, rather than transferring or freezing them earlier at the cleavage stage. The decision to culture embryos to blastocyst rather than an earlier day depends on how many embryos are available, laboratory practice and clinical judgement, and is usually discussed with you during your cycle.

Also known as: extended embryo culture, embryo incubation

Last reviewed: 9 September 2026. Written by the Antega Editorial Team. General information only — always follow the advice of your own clinic, doctor or pharmacist.