Not used in USA
Decapeptyl is a gnrh agonist which is used in ivf, in europe / other countries.
It can be a monthly depot injection, or daily subcutaneous injections. The daily version can be used to prevent you from ovulating before an egg retrieval, or in a microdose flare protocol for 'poor responders'. The depot version can be used before frozen embryo or donor egg cycles. Hard to get pregnant after this med.