GnRH antagonist
Medication that blocks gonadotropin-releasing hormone to prevent premature ovulation during fertility treatment cycles.
Full Definition
A GnRH (gonadotropin-releasing hormone) antagonist is a class of fertility medication used in assisted reproductive technology protocols to suppress the natural luteinizing hormone surge and prevent premature ovulation. Unlike GnRH agonists, antagonists provide immediate suppression without an initial stimulatory phase, allowing for more precise timing of egg retrieval procedures. Common GnRH antagonists include cetrorelix and ganirelix, typically administered as daily subcutaneous injections during the latter part of ovarian stimulation cycles. This medication class has become standard in many IVF protocols due to reduced treatment time and lower risk of ovarian hyperstimulation syndrome.
Usage
Usage note: Distinguish carefully from GnRH agonist, which has opposite initial effect.
In Context
- "The GnRH antagonist was started on stimulation day 6 to prevent premature LH surge." — Treatment protocol
- "Cetrorelix, a GnRH antagonist, was administered subcutaneously for cycle control." — Medication record