Follicle
A small fluid-filled sac in the ovary that contains a developing egg.
In plain English
It's a tiny fluid-filled sac in your ovary that holds and grows an egg.
Why it matters
The number and size of follicles seen on scans during stimulation guides dosing decisions and the timing of your trigger shot.
Related terms
Guides that cover this
Written by patients, not clinicians. This page has not yet been reviewed by a named fertility professional, so it explains published guidance and points you to the original source instead of giving medical advice. It is not medical advice. Decisions about your treatment belong with your own clinic. Read our editorial policy and corrections policy.