Medicines & protocols
In an antagonist protocol, stimulation starts early in the period and a GnRH antagonist is added once follicles reach a certain size to prevent an early LH surge. It is the most widely used protocol because it is shorter, involves fewer injections and allows an agonist trigger where OHSS risk is high.
Also known as: short protocol, antagonist cycle
Related South Africa guides
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.