Eggs, sperm & embryos
Normal fertilisation is confirmed when the embryologist sees two pronuclei — one from the egg and one from the sperm — roughly 16 to 18 hours after IVF insemination or ICSI. Eggs with one, three or more pronuclei have not fertilised normally and are not usually used. Typically around two thirds to three quarters of mature eggs fertilise normally.
Also known as: fertilisation rate, normally fertilised
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.