Thyroid disorders are 5–8x more common in women than men, and they get worse around the same hormonal pivots — postpartum, perimenopause. A 'normal TSH' is one of the most over-trusted lab results in women's health.
Why TSH alone misses the diagnosis
Standard labs accept a TSH up to 4.0–4.5 as normal, but most women feel best below 2.5. And TSH only measures the brain's signal to the thyroid — it tells you nothing about whether T4 is converting to active T3, or whether autoimmune antibodies are quietly destroying thyroid tissue.
The full panel that finds the problem
For any woman with symptoms, this is the minimum:
- •TSH
- •Free T4 (raw material)
- •Free T3 (active hormone)
- •TPO antibodies (autoimmunity)
How thyroid drives 'hormonal' symptoms
Hypothyroidism causes heavy periods, anovulation, low progesterone, miscarriage risk and infertility. Hyperthyroidism causes shorter cycles and anxiety. Subclinical disease often looks like perimenopause. Treating sex hormones without checking thyroid is a common dead-end.
Nutrients that drive thyroid function
Even a perfectly functioning thyroid can't convert T4 to T3 without these:
- •Iron (ferritin >50)
- •Selenium
- •Zinc
- •Iodine (carefully — too much worsens autoimmunity)
- •Vitamin D
Frequently asked
Yes — both hyper- and hypothyroidism reduce fertility and increase miscarriage risk. We test thyroid in every fertility consult.