Thyroid and menopause

The thyroid is a small, butterfly-shaped gland at the front of the neck. The British Thyroid Foundation, the UK charity for people with thyroid conditions, explains that it makes two hormones, thyroxine (T4) and tri-iodothyronine (T3), which set how fast the body's cells work, and that a hormone from the pituitary gland, TSH, tells it how much to make. EMAS, the European Menopause and Andropause Society, describes these hormones as playing a key role in the body's metabolism.

It can go wrong in two directions. An underactive thyroid (hypothyroidism) makes too little hormone, so the body slows down. An overactive thyroid (hyperthyroidism) makes too much, so it speeds up. EMAS published a position statement in 2024 on how thyroid disease and the menopause overlap. It says thyroid disease is common in women in their late reproductive years, around the time perimenopause begins.

No NICE or NHS menopause guidance ties the two together, and the NHS thyroid pages do not mention the menopause. The EMAS statement and the British Thyroid Foundation's pages on thyroid and the menopause are the main sources here.

The NHS website lists the symptoms of an underactive thyroid. Read them next to a list of perimenopause symptoms:

• feeling very tired (fatigue)
• feeling cold more than usual
• weight gain
• constipation
• trouble concentrating or thinking clearly
• low mood or depression
• dry skin, dry hair or hair loss
• a hoarse voice
• irregular or heavy periods

An overactive thyroid has its own list, and parts of it read like a hot flush. The British Thyroid Foundation names tiredness, sweating, struggling with heat, weight loss, poor sleep, shaking and a racing or pounding heart (heart palpitations). With Graves' disease, the eyes can feel gritty and sore.

EMAS adds joint and muscle pain, anxiety, more sweating, sleep problems and a lower sex drive to the symptoms the menopause and thyroid disease can share.

Each can make the other harder to live with. The British Thyroid Foundation says an underactive thyroid and the menopause together add to the load of symptoms a woman carries, which is why it wants both looked after well.

EMAS explains that without a specific sign, such as a swelling in the neck or changes around the eyes, it is hard to pin symptoms on one condition rather than the other, and that this leads to delays in diagnosis. Its answer is for doctors to check thyroid hormones readily in a woman of menopausal age with these symptoms. The British Thyroid Foundation puts it the other way round: thyroid and menopause symptoms are common, vague and overlapping, and it is not unusual for one to be put down to the other.

The NHS website says the most common cause of an underactive thyroid, Hashimoto's disease, is most common in women and usually starts between 30 and 50. In the UK, the British Thyroid Foundation says, the other common cause is the after-effect of treatment for an overactive thyroid or thyroid cancer. An overactive thyroid most often comes from Graves' disease, another autoimmune condition, or from one or more harmless lumps (nodules) making too much hormone. At the foundation's 2023 webinar, its experts said Graves' disease is most common between 30 and 60, far more common in women than men, and that about half of the people who have it report a family history.

• A blood test. The NHS website says an underactive thyroid is diagnosed with a blood test measuring TSH and thyroxine. See is there a test for menopause? for what blood tests can and cannot tell you about the menopause itself.
• A second test if the first is borderline. The British Thyroid Foundation says borderline results are common now that more tests are done, and that being unwell for another reason can throw a result off once, so a doctor will usually repeat it. A normal repeat makes the thyroid an unlikely cause. A result that stays borderline or gets worse may be subclinical hypothyroidism, which does not always cause symptoms and can go on to become an underactive thyroid. A swelling in the neck may need a scan.
• A check after an early menopause. If you have premature ovarian insufficiency, the British Thyroid Foundation says it is linked with autoimmune thyroid disease, with thyroid problems in 14 to 27% of women who have it, and that they should be tested for thyroid antibodies and TSH when it is found.
• Telling your doctor about supplements. EMAS notes that many supplements women take in midlife for hair and skin contain biotin, which can give false results on some thyroid blood tests, and asks doctors to find out about every medicine a woman takes, including those bought over the counter. If you take biotin, tell your doctor or the lab before the test.
• Sleep. The British Menopause Society's sleep guidance asks doctors to consider thyroid disease when a woman's sleep is disturbed, and to test if there is concern about it. See sleep disruption.
• A yearly check once you are on treatment. The British Thyroid Foundation says a yearly blood test is usual, and shows whether the dose needs to change. It adds that the dose a woman needs can shift through the menopause transition, with her changing estrogen levels and her weight.

The British Thyroid Foundation says an underactive thyroid is usually looked after by a GP, and an overactive thyroid, at least at first, by a thyroid specialist (an endocrinologist). The NHS website says an underactive thyroid is usually treated with tablets that replace the missing hormone, called levothyroxine, and the foundation names levothyroxine as the replacement recommended in the UK. With a borderline result, it says a doctor may try treatment to see whether symptoms improve. For an overactive thyroid, EMAS says treatment depends on the cause, and the foundation lists antithyroid medicines, radioactive iodine and surgery.

For women on thyroid treatment who are thinking about HRT, EMAS calls HRT a safe option with a thyroid condition, and makes three further points. It says no data on interactions between HRT and thyroid medicines have been reported. It notes that estrogen taken by mouth can raise a protein that carries thyroid hormone in the blood, which can change test results and mean a levothyroxine dose needs adjusting. And it warns that too much thyroid treatment after the menopause is linked to thinner bones, so the dose matters.

The British Thyroid Foundation calls HRT the most effective treatment for menopause symptoms, and says thyroid treatment does not rule it out. Its detail is about how HRT is taken. With HRT tablets, a woman already on levothyroxine may need a higher dose, so it suggests rechecking thyroid tests after starting. Estrogen through the skin, as a gel, spray or patch, should not change the dose, and the progesterone in HRT is not expected to make much difference. Women with no thyroid problem usually adjust well to HRT, it says.

At the foundation's 2023 webinar, one of its experts was less certain about patches and gels: the evidence is not clear, and some may be absorbed in a way that affects levothyroxine, while vaginal estrogen is unlikely to be absorbed in amounts that matter. The same expert's advice was that if you are on levothyroxine, have been well, and suddenly feel unwell, a thyroid test is a simple, cheap check, and a small change in dose can make a big difference.

The webinar covered more ground for women with a thyroid condition:

• After thyroid cancer, the experts said that a history of thyroid cancer does not rule out HRT, that the levothyroxine dose may need adjusting once HRT starts, and that evidence of estrogen driving thyroid cancer is patchy and unclear.
• After a surgical menopause, symptoms tend to be severe, and they said hormone therapy is usually given, with testosterone appearing to help more in women whose ovaries were removed. The thyroxine dose often needs fine-tuning after HRT starts. The foundation's FAQs add that testosterone at normal blood levels should not affect thyroid medicine.
• On weight, they said losing weight is hard for everyone, and that a woman whose TSH has risen, perhaps after starting HRT, may not be on the right levothyroxine dose. Once the dose is right, they said, losing weight should be no harder for her than for anyone else.
• On HRT in general, they said its main purpose is to treat menopause symptoms, that there is no time limit on it, that there is no international agreement it prevents dementia, with studies pointing both ways, and that it is not recommended to prevent osteoporosis after a natural menopause. For a very early menopause, under 40, they recommend it to protect the bones and the heart. Under 60, they said, HRT can usually be taken safely, and a woman of 65 who still has symptoms is not ruled out from a trial of it.
• On selenium, they said it may bring thyroid antibody levels down, but trials have not shown it improves thyroid function or symptoms. The evidence for it is mainly in thyroid eye disease.

The British Thyroid Foundation does not recommend compounded, unlicensed HRT for menopause symptoms. It says how safe and effective it is remains unclear, it may interact with other medicines, and there are reports of extra vaginal bleeding and womb cancer with it. See bioidentical hormones.

What goes in alongside the tablet matters too. The foundation says thyroid tablets are best taken on an empty stomach, that food, milk, tea and coffee taken too soon after get in the way, and that a calcium carbonate supplement taken at the same time can cut how much thyroxine is absorbed by nearly a third. It advises a gap for both. Ask your pharmacist how long.

• Soya. The foundation says soy foods may reduce how well thyroxine is absorbed and raise the dose needed, though there is little evidence they affect a thyroid that works normally. In someone with borderline thyroid levels and too little iodine, soy may raise the risk of an underactive thyroid. See phytoestrogens.
• Iodine. Too much can make a thyroid condition worse. The foundation advises against high-dose iodine supplements and kelp, whose iodine content varies widely, and notes that some menopause supplements contain a lot of iodine. Before starting any herbal or other remedy, it suggests asking a doctor or pharmacist how it might affect your thyroid, and checking your medicine's leaflet for interactions. See supplements.
• Bones. The foundation adds to EMAS's warning: after the menopause an overactive thyroid is a risk factor for a broken hip, and an underactive thyroid treated too heavily raises the risk of fractures too. See osteoporosis.

If tiredness, weight changes, low mood or changes in your periods are wearing you down, book an appointment and ask about both your thyroid and perimenopause. You do not have to choose one.

If you already have a thyroid condition and new symptoms appear in your forties, mention them. EMAS says the two conditions can sit side by side. If you start HRT tablets, or suddenly feel unwell on levothyroxine, ask whether your thyroid needs checking.

If your mother or a sister takes thyroid tablets, say so. EMAS asks that decisions about treating either condition take in a woman's family history, her preferences and her own part in the choice.

In Ramadan, women on levothyroxine often ask how to time it around sehri and iftar, since the British Thyroid Foundation says it works best on an empty stomach with a gap before food and drink. That is a question for whoever prescribes it, before the month starts. Questions about the fast itself belong with a qualified scholar.