Anatomy & hormones
An ovarian follicle is a small fluid-filled structure that houses and nurtures a developing oocyte. Each cycle, a group of follicles begins to grow, and usually one becomes dominant and releases its egg at ovulation. In IVF, ovarian stimulation medicines encourage several follicles to grow together, which are monitored by ultrasound and used to time the trigger injection and egg retrieval. The antral follicle count, seen on early-cycle ultrasound, is used to estimate ovarian reserve.
Also known as: ovarian follicle, follicles
Sources
- Indian Council of Medical Research (icmr.gov.in)
- ICMR Standard Treatment Workflows (icmr.gov.in/standard-treatment-workflows-stws)
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.