Symptoms of Thyroid Disease in a Woman: What to Know

Thyroid problems are common in Australian women, and they usually come on slowly. The symptoms of thyroid disease in a woman, such as tiredness, weight change, feeling cold or hot, and changes to periods, are easy to put down to stress or a busy life. This guide covers an underactive and an overactive thyroid, the blood test that tells them apart, and when to see a doctor about the symptoms of thyroid disease in a woman.

Key takeaways

• Thyroid disease is several times more common in women than in men, and more common with age and after having a baby.
• An underactive thyroid slows the body down; an overactive thyroid speeds it up.
• A blood test of TSH and free T4 confirms or rules out a thyroid problem.
• Both are treatable, and most women feel well again once their hormone levels are right.

What an Underactive Thyroid Is

An underactive thyroid, or hypothyroidism, means the thyroid gland in your neck doesn't make enough thyroid hormones to keep your body running at its normal pace. It's the most common thyroid disorder in women, and among the most common symptoms of thyroid disease in a woman is tiredness that doesn't lift.

Levothyroxine, the usual replacement tablet, is only available on prescription in Australia.

Symptoms of an Underactive Thyroid Before It's Diagnosed

Hypothyroidism usually comes on over months or years, so the symptoms of thyroid disease in a woman are often missed at first. What you might notice if you have hypothyroidism is tiredness and fatigue, weight gain without eating more, feeling cold when others aren't, constipation, dry skin, thinning hair and brittle nails.

Other common underactive thyroid symptoms in women are heavy or irregular periods, low mood, poor memory or slowed thinking, aching muscles and joints, a puffy face and a hoarse voice. Hypothyroidism can also cause high cholesterol and a slow heart rate. Mild hypothyroidism may cause no symptoms at all and be found only on a blood test, and in older women it's easily mistaken for ageing.

Because these symptoms of an underactive thyroid overlap with depression, menopause, iron deficiency and plain exhaustion, hypothyroidism is diagnosed with a blood test, not by symptoms alone.

Common Causes of Thyroid Disease in Women

Most thyroid disease in Australian women is autoimmune, which means the immune system targets the thyroid. Hashimoto's disease damages the gland so it makes less hormone, causing hypothyroidism. Graves' disease does the opposite: the thyroid gland produces more hormone than the body needs, causing hyperthyroidism. Both run in families and are more common in women with other autoimmune conditions, such as type 1 diabetes or coeliac disease.

Other causes include thyroiditis, an inflammation of the gland that can follow a viral illness or a pregnancy, some medicines, earlier treatment for a thyroid problem, and iodine deficiency, which is less common in Australia now that most bread is made with iodised salt. An overactive thyroid can feel like anxiety, which is one reason the symptoms of thyroid disease in a woman are easy to misread. Treatment for thyroid disease depends on the cause, so your doctor looks for it first.

Signs of an Overactive Thyroid in Women

An overactive thyroid, or hyperthyroidism, is when the thyroid gland produces too much thyroxine and other thyroid hormones, which speeds the body up. Signs include weight loss despite a good appetite, a racing or irregular heartbeat, feeling shaky or on edge, sweating and disliking the heat, loose or frequent bowel motions, trouble sleeping, and lighter or less frequent periods. Graves' disease can also make the eyes look prominent or feel gritty. This thyroid disorder is less common than hypothyroidism, and a thyroid test confirms it.

How Thyroid Disease Is Treated

Treatment depends on whether the thyroid is underactive or overactive. Hypothyroidism is treated with a daily thyroid hormone tablet that replaces what your gland can't make, so your body has enough thyroid hormones again; it's usually lifelong, and the dose is set by blood tests every six to eight weeks at first, then about once a year. Hyperthyroidism is treated with antithyroid medicines, radioactive iodine or, less often, surgery, and a beta blocker can ease shaking and a racing heart while the others take effect. These medicines are prescription only in Australia, and your doctor checks your hormone levels to adjust the dose.

The Thyroid Function Test and TSH Levels

A thyroid function test is a blood test that measures thyroid-stimulating hormone (TSH), and often free T4, to show how well your thyroid is working. TSH comes from the pituitary gland at the base of the brain and tells the thyroid how hard to work. When the thyroid is underactive, TSH rises, and when it's overactive, TSH falls.

A typical adult TSH range is about 0.4 to 4.0 mIU/L, though laboratories differ. A high TSH with a low free T4 points to hypothyroidism, and a low TSH with a high free T4 or T3 points to an overactive thyroid. Your doctor may add thyroid antibodies to look for Hashimoto's or Graves' disease.

Your doctor may suggest the test if you have fatigue, weight change or changes to your periods, if you're planning a pregnancy or have recently had a baby, or to check how treatment is going. No fasting is needed, and your doctor reads the thyroid function results alongside your symptoms.

When to See a Doctor About Thyroid Symptoms

See a doctor if you have several of the common symptoms above for more than a few weeks, especially ongoing fatigue, unexplained weight change or changes to your periods. See one sooner if you notice a lump or swelling in your neck, which needs an examination in person, or if you've had a baby in the past year, because postpartum thyroiditis often causes an over-active thyroid first and an underactive one later. If you already take hormone replacement for your thyroid and the symptoms come back, ask for your dose to be checked. Call 000 or go to an emergency department for a very fast or irregular heartbeat with chest pain or fainting, sudden confusion, or a high fever with a racing heart.

How Thyroid Problems Affect Periods and Fertility

Thyroid hormone affects the menstrual cycle, so a thyroid problem often shows up in your periods. Hypothyroidism can make periods heavier, longer or irregular, while hyperthyroidism tends to make them lighter or less frequent. Untreated thyroid disease can make it harder to get pregnant and raises the risk of miscarriage, and its symptoms can look like polycystic ovary syndrome, which your doctor may check for too. Pregnancy needs more thyroid hormone, so if you take thyroid medicine and want to have a baby, see your doctor early. Women trying to conceive, pregnant or breastfeeding are advised to take 150 micrograms of iodine a day to prevent iodine deficiency, unless their doctor advises otherwise.

Underactive Versus Overactive Thyroid

An underactive thyroid slows everything down: you feel tired, cold and sluggish, and your heart rate falls. An overactive thyroid and its symptoms are the opposite: you feel wired, hot and restless, lose weight and your heart races. On a blood test, thyroid-stimulating hormone is high when the thyroid gland is underactive and low when it's overactive. Some women move from one to the other, as with postpartum thyroiditis or after treatment for an overactive thyroid, so the test is repeated over time.

Summary

This guide covered the symptoms of thyroid disease in a woman, from an underactive to an overactive thyroid, and the blood test that tells them apart. If you recognise the symptoms of thyroid disease in a woman in yourself, a Medio GP can talk them through by phone, request a thyroid function test, and send an eScript or a referral if they think it's right.

Frequently asked questions

What is Hashimoto's disease?

Hashimoto's disease is an autoimmune condition in which the immune system slowly damages the thyroid gland, a small butterfly-shaped gland at the front of your neck. It's the most common cause of hypothyroidism in Australia, is far more common in women and often runs in families. It's found with a TSH test and thyroid antibodies, and treated with daily thyroid hormone if the thyroid becomes underactive.

What are the symptoms of hypothyroidism in teenagers?

Teenagers with hypothyroidism may feel tired and low, gain weight, feel the cold, have dry skin, grow more slowly, have delayed or irregular periods and find school harder. These signs have many causes, so a teenager should see a GP in person; Medio's doctors see adults 18 and over.

Can a doctor help with symptoms of thyroid disease in woman?

Yes. A doctor can go through your symptoms, request a blood test for your thyroid and explain the results, then start or adjust treatment if you need it. A Medio GP can do this by phone and send an eScript if they think it's right, while a lump in the neck needs an examination in person.

What are the symptoms of central hypothyroidism?

Central hypothyroidism has the same symptoms as other hypothyroidism, such as tiredness, feeling cold and weight gain, but the cause is in the pituitary gland rather than the thyroid. It's rare. Hormones are the body's chemical messengers, and they impact your energy, weight, temperature and periods; here the pituitary sends too little TSH, so a low free T4 is the clue.

What are 10 warning signs of thyroid?

Ten warning signs are tiredness, weight change, feeling cold or hot, a racing or slow heart, changes to your periods, thinning hair, dry skin, low mood or anxiety, poor memory and a swelling in the neck. Common signs and symptoms of thyroid dysfunction overlap with many other conditions, so a blood test is needed to know.

What are the worst symptoms of hypothyroidism?

Severe untreated hypothyroidism can cause deep tiredness, depression, slowed thinking, a very slow heart rate and, rarely, myxoedema coma, with confusion, drowsiness and a low body temperature; call 000 for those. How common is hypothyroidism? It's common, especially in women and older people, and it can cause other problems such as raised cholesterol, which treatment prevents.