Medical disorders in pregnancyFree in the app
Thyroid disease — 2026 update
New ATA guideline (May 2026).
Source: ATA 2026 · endorsed by ACOG, EBCOG, ESHREHyperthyroidism
| First trimester | Use PTU (switch from carbimazole/methimazole before conception or very early; weeks 6–10 most sensitive). |
|---|---|
| After 16 weeks | Continuing PTU or switching back is now an individual decision. |
| Target | Free T4 at the upper end of normal. |
| Gestational thyrotoxicosis | With hyperemesis — do not treat with antithyroid drugs. |
| TRAb | Check at booking and 18–22 weeks; high levels need fetal surveillance. |
Hypothyroidism
| Overt | Treat promptly. Expect to increase levothyroxine by 25–50%. Target TSH below 2.5. |
|---|---|
| Subclinical | Confirm it persists. Start levothyroxine only in the first trimester. |
| TPO antibodies alone | Not a reason to treat. |
| Screening | Risk-based; measure free T4 with TSH. |
Thyroid storm: PTU, then iodide 1 hour later, propranolol, hydrocortisone, ICU.
A summary for trained clinicians. Always check the full guideline, the patient in front of you and your hospital's protocol. Spotted an error? Tell us.