Fertility Glossary

Agonist trigger

Using a GnRH agonist instead of hCG for final egg maturation.

Medicines & protocols

An agonist trigger uses a GnRH agonist to release the body's own LH surge, maturing the eggs while substantially lowering the risk of OHSS compared with an hCG trigger. It can only be used in antagonist protocols, and because it shortens luteal support from the body, clinics usually freeze the embryos or adjust hormone support carefully.

Also known as: Lucrin trigger, GnRH agonist trigger, dual trigger

Related South Africa guides

The IVF trigger injection: timing and why it matters

Sources

ESHRE guidelines and patient information

Last reviewed: 8 September 2026. Written by the Antega Editorial Team. General information only — always follow the advice of your own clinic, doctor or pharmacist.

Related terms

Trigger injection

The final injection that matures the eggs before collection.

hCG trigger

Using hCG to mature the eggs before collection.

Ovarian hyperstimulation syndrome (OHSS)

An over-response to fertility medication causing swollen, painful ovaries.

Freeze-all cycle

An IVF cycle where every suitable embryo is frozen and transfer happens later.

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