What Are the Causes of Fluctuating Thyroid Levels?

TSH, which is also called thyroid stimulating hormone or thyrotropin, is the primary hormone that is tested for thyroid disorders. However, the level of this hormone in your body can fluctuate for a number of reasons, thereby disrupting the testing process.

Timing

• If you take a hormone replacement pill for hypothyroidism, the timing of when you take your pill can affect the efficacy of the test. You should always take your medication at the same time of day, according to Thyroid-Info.com, as this will ensure that you have a steady dose of the hormone in your system.

Food

• Taking your medication with food can also reduce your body's ability to absorb the hormone properly. Take your medication either one hour before, or two hours after eating. Eating too many soy products, according to Thyroid-Info, can also cause fluctuation in TSH levels in patients with autoimmune thyroid disease.

Calcium and Iron Supplements

• Calcium and iron supplements should be taken 12 hours after your thyroid medication, according to Thyroid-Info.com. Both of these supplements, though very important parts of your diet, interfere with your body's absorption of hormone replacement medications.

Seasonal Changes

• The seasons can affect thyroid levels in some patients. Cold weather induces higher TSH levels, and hot weather induces lower levels. This means that you may be more hypothyroidic in the winter months, while experiencing a hyperthyroid state in the summer months.

Other Hormonal Fluctuations

• Other hormone levels can have an impact on your thyroid levels. Estrogen and progesterone, in particular, are often used in hormone replacement therapy and in birth control measures. These can impact thyroid levels and should be accounted for.