Medicines & protocols
GnRH antagonists block the pituitary immediately rather than after a period of suppression, so they are usually started once follicles reach a certain size. Antagonist protocols are shorter and lower the risk of OHSS because an agonist trigger can then be used. They are given as daily subcutaneous injections.
Also known as: antagonist, cetrorelix, ganirelix, antagonist injection
Related South Africa guides
Sources
- SAHPRA (South African Health Products Regulatory Authority)
- 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.