Subclinical Thyroid Disease & Pregnancy: New Guidelines
- Treating subclinical thyroid disease during pregnancy involves several key considerations, according to Caroline T.
- Nguyen, assistant professor at USC Keck School of Medicine, noted that much has been learned sence the American Thyroid Association's 2017 guideline.
- The discussion addressed thyroid-stimulating hormone (TSH) cutoffs and which patients shoudl be considered for treatment regarding subclinical hypothyroidism.
New guidelines impact how to treat subclinical hypothyroidism during pregnancy. Dr. Caroline T. Nguyen sheds light on recent data, including thyroid-stimulating hormone (TSH) cutoffs and treatment strategies. Discover the key considerations for pregnant women with subclinical thyroid disease, notably regarding fertility. Shared decision-making is crucial for persistent cases, addressing the complexities of thyroid hormone demand during pregnancy. Explore the differing viewpoints from the American Society for reproductive Medicine and the American Thyroid Association, offering clarity on when to treat. This expert analysis, featured on News Directory 3, simplifies thes vital updates.What’s next in the ongoing discussion?
Treating Subclinical Hypothyroidism During Pregnancy: Key Considerations
Updated May 28, 2025
Treating subclinical thyroid disease during pregnancy involves several key considerations, according to Caroline T. Nguyen, MD. In an interview with Trevor Angell, MD, Nguyen discussed recent data impacting treatment decisions for subclinical hypothyroidism in pregnant women.
Nguyen, assistant professor at USC Keck School of Medicine, noted that much has been learned sence the American Thyroid Association’s 2017 guideline. She and Angell, associate professor at USC, are course directors for the 2025 USC Peter A. Singer Thyroid Symposium.
The discussion addressed thyroid-stimulating hormone (TSH) cutoffs and which patients shoudl be considered for treatment regarding subclinical hypothyroidism.
Q&A Highlights
Defining Subclinical Hypothyroidism: Nguyen explained that subclinical hypothyroidism is defined by an abnormal TSH but normal thyroxine (T4) levels. She noted the confusion surrounding different cutoffs for fertility and pregnancy.
TSH Levels: nguyen suggested using 4 mU/L as the upper limit of normal when lab-specific ranges are unavailable. Subclinical hypothyroidism is typically a TSH between 4 and 10 mU/L with normal T4. A TSH over 10 mU/L is generally considered overt hypothyroidism.
New Data As 2017: High-quality randomized controlled trials have provided more data. Treating patients with TSH between 2.5 and 4 mU/L who are trying to conceive has not shown meaningful outcome differences, even in those with thyroid peroxidase antibodies.
Who to Treat: Nguyen emphasized that guidelines vary. The American Society for Reproductive Medicine does not recommend treating anyone with subclinical hypothyroidism,even when planning for fertility treatments. The ATA will advocate repeating tests to confirm persistent subclinical hypothyroidism before considering treatment.
Shared Decision-Making: If subclinical hypothyroidism is persistent, Nguyen advises a shared decision-making approach, discussing the pros and cons of treatment. Pregnancy increases the demand for thyroid hormone, and ovarian stimulation treatments can effect thyroid function.
What’s next
nguyen will further discuss subclinical thyroid disease in pregnancy at the USC Peter A. singer Thyroid Symposium on May 31.