We received this excellent question from a woman whose email address seemed to have a typo in it, so we were unable to respond directly to her — we hope she’s reading this!
The most common reason for a low TSH is taking too much thyroid medication. If you aren’t taking medication of that kind, it could be a naturally low TSH — which, if chronic, is most often because of Graves’ disease.
You can confirm or refute this with:
- A blood test for “thyroid receptor antibody”
- A thyroid ultrasound
Now, if your doctor doesn’t think your low TSH is anything to worry about, should you get a second opinion?
Perhaps yes, if you have symptoms of hyperthyroidism now (like a racing resting heartbeat) — or, if a repeat TSH in 4-8 weeks is still low. Sometimes your TSH just rebalances itself, so no deeper testing is necessary.
I hope that’s helpful — sometimes just watching and waiting really is appropriate, even when trying to get pregnant.