Follicle

Follicles are measured on ultrasound during treatment, and a mature one is typically 16 to 22 mm before the trigger. Not every follicle contains a usable egg, so follicle counts and egg numbers rarely match exactly.

Also known as: ovarian follicle

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