Estradiol (E2)
Also written as oestradiol
A form of oestrogen produced by growing follicles, measured by blood test to track response during ovarian stimulation.
In plain English
It's a hormone level checked during your scans and bloods to see how your follicles are growing.
Why it matters
Rising levels alongside follicle growth help your clinic time your trigger shot and watch for signs of overstimulation.
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.