Trigger shot

Written by Zayn Miah & R KhanomLast updated 17 September 2026Not clinically reviewed

A single injection given near the end of stimulation to complete the final maturation of eggs before collection.

In plain English

It's the final injection of your stimulation phase, timed precisely to ripen your eggs ready for collection about 36 hours later.

Why it matters

Its timing has to be exact, since egg collection is scheduled around it, so it's usually the one injection with a very specific time attached.

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.