Thyroid function and menopause

Thyroid hormones regulate your metabolism. Sometimes too much hormone is produced or other times, not enough. Fluctuating and falling levels of estrogen can also have an impact on how your thyroid and thyroid hormones function.

The thyroid is a butterfly-shaped gland that’s located at the front of the neck. It produces two hormones, thyroxine (T4) and tri-iodothyronine (T3), which are then released into the bloodstream.

These hormones regulate your body’s metabolism, or the speed at which the cells in your body work. So if the thyroid produces too much of these hormones, your metabolism will speed up; if it produces too little, your metabolism will slow down.

Thyroid disorders

Thyroid disorders are very common, and can be temporary or permanent. Around one in 20 people has a thyroid disorder, and women are 10 times more likely to be affected than men.

There are two main types of thyroid disorder:

• Hypothyroidism (underactive thyroid) – when not enough thyroid hormones are produced
• Hyperthyroidism (overactive thyroid) – when too much thyroid hormones are produced

Around 3% of women over 50 are currently being treated for an underactive thyroid (hypothyroidism) with the thyroid hormone replacement medication thyroxine (levothyroxine). Overactive thyroid (hyperthyroidism) is less common, affecting 1.5% of women over the age of 50.

Typical symptoms of hypothyroidism may include:

• Tiredness
• Feeling cold
• Weight gain
• Poor concentration
• Constipation
• Depression

Common symptoms of hyperthyroidism may include:

• Weight loss
• Heat intolerance
• Fatigue
• Anxiety
• Difficulty sleeping
• Palpitations

Diagnosis and treatment

Sometimes there are very few symptoms of thyroid disease, so a blood test is needed before a diagnosis can be made.

Thyroid disorders have a number of possible causes, but the most common cause is autoimmune thyroid disease, where the body’s immune system attacks thyroid cells. As a result, the thyroid can become under- or overactive. Thyroid disorders can sometimes run in families.

Most thyroid disorders can be treated with medication, and hyperthyroidism may also be treated with radioiodine treatment or surgery.

Menopause and thyroid disorders

Thyroid disorders can have similar symptoms to those caused by perimenopause and menopause, and hypothyroidism can also make menopause symptoms worse. Thyroxine (T4) needs to be converted to triiodothyronine (T3) (the active part of the hormone) by your cells. Various factors can affect this conversion such as insulin resistance and stress (common during the perimenopause and menopause). Fluctuating estrogen levels can have an impact on thyroid function.

If you have a thyroid disorder and are taking HRT, oral estrogen tablets should be avoided as it can raise the ‘thyroid binding globulin’ (TBG) which decreases available thyroxine. Transdermal estrogen (through the skin) such as an estrogen patch, gel or spray does not affect TBG and is suitable to take.

If you’ve been diagnosed with a thyroid disorder and are not taking HRT, falling levels of estrogen at perimenopause and menopause may mean that your dose of thyroxine needs to be altered.

If you are taking HRT, this can affect the way that your thyroid medication is absorbed, which means that your doctor may need to increase your dose of thyroxine in order to control your symptoms. For this reason, it’s wise to have your thyroid function checked soon after you start taking HRT.

You do not have to delay starting HRT if you have had abnormal results from your thyroid blood test. Many women find that taking HRT actually improves their thyroid function.

Nutritional support can help with more efficient thyroxine processing, and it may be worth a consultation with a registered nutritional therapist who can offer individualised guidance on this.

Phytoestrogen supplements

If you’re taking phytoestrogen supplements (plant-based estrogen), either because you’re unable to take HRT, or choose not to, these may also affect thyroid function and interfere with the absorption of thyroxine. For this reason, it’s important to get advice from your doctor before taking any supplements or herbal remedies.