In IVF, which pharmacological protocol is used to prevent a premature LH surge during controlled ovarian hyperstimulation using a GnRH antagonist?

• A GnRH agonist given from Day 21 of the previous cycle (long protocol)
• B Oral combined pill pre-treatment to synchronize follicles
• C Letrozole from Day 2–6 to inhibit LH
• D GnRH antagonist (cetrorelix or ganirelix) given from Day 6 of stimulation or when lead follicle reaches 14 mm ✓

Explanation

In the GnRH antagonist protocol for IVF, the antagonist (cetrorelix or ganirelix) is started on Day 5–6 of gonadotropin stimulation or when the lead follicle reaches 14 mm in diameter. GnRH antagonists immediately suppress LH within hours, preventing a premature LH surge. The long GnRH agonist protocol uses daily agonist from the mid-luteal phase of the preceding cycle to achieve pituitary downregulation before starting gonadotropins.

Reference: Shaw's Textbook of Gynaecology, 17th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.