Is gonadotropin-releasing hormone agonist usage really leading to thyroid dysfunction?

Area of Science:

• Endocrinology
• Reproductive Medicine
• In Vitro Fertilization (IVF)

Background:

• Gonadotropin-releasing hormone agonists (GnRHa) are utilized in assisted reproductive technologies.
• GnRHa can potentially affect both sex and thyroid hormone levels.
• Understanding the impact of GnRHa on thyroid function is crucial for optimizing IVF protocols.

Purpose of the Study:

• To investigate the effect of GnRHa administration on thyroid hormone levels.
• To assess changes in serum TSH, free T3, and free T4 following GnRHa treatment in women undergoing IVF.

Main Methods:

• A cross-sectional study involving 41 women undergoing a single IVF cycle.
• Serum T3, T4, and TSH levels were measured before and two weeks after GnRHa administration.
• Patients were grouped based on their thyroid hormone levels pre- and post-treatment.

Main Results:

• A statistically significant decrease in mean TSH levels was observed after GnRHa administration (p < 0.05).
• Serum-free T3 and T4 levels did not show a statistically significant change.
• The observed changes were evaluated two weeks post-GnRHa administration.

Conclusions:

• GnRHa treatment leads to a reduction in serum TSH levels.
• Serum-free T3 and T4 levels remain stable in the early period after GnRHa administration.
• The early measurement (two weeks) might explain the lack of significant change in free thyroid hormones.