Thyroid function testing prior to fertility treatment: will we ever agree?

Area of Science:

• Endocrinology
• Reproductive Medicine
• Women's Health

Background:

• Thyroid disorders, particularly hypothyroidism, are highly prevalent in women and impact fertility and pregnancy.
• Subclinical hypothyroidism (SCH), characterized by elevated thyroid-stimulating hormone (TSH) with normal thyroid hormone levels, often presents asymptomatically but carries risks for adverse outcomes.
• Thyroid autoimmunity (TAI) can coexist with SCH and may influence its progression, especially during pregnancy.

Purpose of the Study:

• To review the current discourse and varied recommendations regarding routine thyroid function testing in women experiencing subfertility.
• To highlight the discordance in clinical guidelines for diagnosing and managing SCH in this specific population.

Main Methods:

• Literature review and analysis of existing clinical guidelines from major international thyroid and obstetrics/gynecology associations.
• Examination of the diagnostic criteria for SCH, focusing on the lack of consensus for the upper limit of normal TSH.
• Discussion of the implications of these variations for routine screening protocols in fertility settings.

Main Results:

• Significant variation exists among prominent health organizations (e.g., ATA, ETA, RCOG vs. NICE, ASRM) regarding routine thyroid screening for subfertile women.
• Some guidelines recommend TSH screening with or without antibody testing, while others do not support routine testing.
• The lack of a unified TSH threshold contributes to diagnostic and therapeutic inconsistencies.

Conclusions:

• There is a notable lack of consensus on routine thyroid function testing for subfertile women, leading to varied clinical practice.
• An updated American Thyroid Association guideline, expected to include subfertility and gain international endorsement, is anticipated to address these discrepancies.
• Clarification of screening recommendations is crucial for optimizing fertility outcomes and managing risks associated with subclinical thyroid dysfunction.