Anatomy
In a natural cycle several follicles begin to grow, but usually only one becomes dominant, reaching about 18–24 mm before releasing its egg. The rest stop growing and break down. Fertility medicines used in IVF override this selection so that many follicles develop together.
Also known as: lead follicle
Sources
- Healthdirect Australia (healthdirect.gov.au)
- Pregnancy, Birth and Baby (pregnancybirthbaby.org.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.