GnRH Agonists

Gonadotropin-releasing hormone (GnRH) agonists can cause temporary infertility because they suppress the hypothalamic-pituitary-gonadal (HPG) axis, leading to a significant reduction in gonadotropins (LH and FSH) and, consequently, sex hormone production. This suppression prevents ovulation in women and spermatogenesis in men.

Examples: Lupron (Leuprolide), Synarel, Zoladex

Mechanism of Action:

• Initially, GnRH agonists cause a flare effect, temporarily increasing LH and FSH secretion.

• With continuous use, they desensitize the GnRH receptors in the pituitary gland, leading to decreased secretion of LH and FSH.

• In women, this results in estrogen suppression, preventing ovulation.

• In men, testosterone levels drop, leading to a cessation of sperm production.

  
  

Who It’s For:

-Women undergoing IVF to prevent premature LH surges.
-Women with endometriosis (Lupron helps reduce symptoms).
-Women with PCOS to improve ovarian response in IVF.

How It’s Taken:

• Typically started in the luteal phase (mid-cycle) or before ovarian stimulation.

• Can be used as a "trigger shot" in IVF instead of hCG to reduce OHSS risk.

Uses Related to Infertility Treatment:

• Controlled Ovarian Stimulation (COS): GnRH agonists are used in assisted reproductive technologies (ART), like IVF, to prevent premature LH surges that could cause early ovulation.

• Endometriosis & Uterine Fibroids: They are used to reduce estrogen levels and shrink lesions, which may improve fertility after stopping treatment.

• Polycystic Ovary Syndrome (PCOS): Sometimes used in fertility protocols to help regulate ovulation.Success Rates:

• Reduces the risk of premature ovulation and cycle cancellation.

• Improves egg retrieval rates in IVF.

Benefits:

- Better control over ovulation timing.
- Helps thin the uterine lining in women with endometriosis.
- Lowers the risk of Ovarian Hyperstimulation Syndrome (OHSS).

Side Effects:

• Hot flashes, headaches

• Mood swings

• Temporary menopause-like symptoms

Reversibility:

• The infertility caused by GnRH agonists is usually temporary.

• Once the medication is discontinued, the HPG axis resumes normal function, and fertility typically returns within a few months.

• In some cases, prolonged use may lead to delayed recovery, but this is uncommon.