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Hypothyroidism (under-active thyroid) is a condition in which your thyroid gland doesn't produce enough of certain important hormones. Hypothyroidism upsets the normal balance of chemical reactions in your body.


  • Women have been seen to have a higher risk than men.

  • Risk increases with age especially if you are over sixty years of age.

  • Having a family history of any thyroid disease increases your risk as well as having a first-degree family member who has hypothyroidism.

  • Autoimmune diseases such as type 1 diabetes or celiac disease has been seen to increase the risk.

    • NOTE: Celiac disease is an autoimmune disease that is inherited. An inflammatory reaction occurs after eating gluten activates the immune system. This immune response attacks the small intestine and as a results causes damage to it. [6]

  • Receiving radiation therapy to your neck or upper chest increase the risk.

  • Being treated with radioactive iodine or anti-thyroid medications may cause hypothyroidism if the dosage is exceeded.

  • Surgery to the thyroid may cause hypothyroidism.

  • Pregnancy of six months postpartum may cause hypothyroidism.

CAUSES [4;5]

  • Thyroiditis: which is inflammation of the thyroid gland, which leaves some of the cells of the gland damaged or dead and unable to produce sufficient hormone.

  • Certain medications such as those needed to treat heart problems, psychiatric conditions and cancer may have an effect on the production of the thyroid hormone.

  • Having too little iodine in the diet, as the body does not produce it and it is necessary for the production of the thyroid hormone.

  • Born with a thyroid gland that did not develop properly and thus it is unable to perform its function properly.

  • Having a pituitary disease or damage to the pituitary can cause hypothyroidism as the pituitary releases a hormone which stimulates the production of the thyroid hormone.

  • A rare cause would be a disease of the hypothalamus which releases a hormone that stimulates the pituitary and thus the production of the thyroid hormone.

  • Other factors that cause hypothyroidism are those mentioned in risk factors such as an over -response to hyperthyroidism treatment, thyroid surgery, radiation therapy and pregnancy.


  • Fatigue

  • Increased sensitivity to cold

  • Constipation

  • Dry skin

  • Weight gain

  • Puffy face

  • Hoarseness

  • Muscle weakness

  • Elevated blood cholesterol level

  • Muscle aches, tenderness and stiffness

  • Pain, stiffness or swelling in your joints

  • Heavier than normal or irregular menstrual periods

  • Thinning hair

  • Slowed heart rate

  • Depression

  • Impaired memory



  • Goiter - constant stimulation of your thyroid to release more hormones may cause the gland to become larger.

  • Heart problems - increased risk of heart disease, primarily because high levels of low-density lipoprotein (LDL) cholesterol — the "bad" cholesterol - Hypothyroidism can also lead to an enlarged heart and heart failure.

  • Mental health issues - depression and slowed mental functioning.

  • Peripheral neuropathy - damage to the nerves that carry information from your brain and spinal cord to the rest of your body, for example, your arms and legs. Signs and symptoms of peripheral neuropathy may include pain, numbness and tingling in the area affected by the nerve damage. It may also cause muscle weakness or loss of muscle control.

  • Myxoedema - rare, life-threatening condition is the result of long-term, undiagnosed hypothyroidism. Its signs and symptoms include: low blood pressure, decreased breathing, decreased body temperature, unresponsiveness and even coma.

  • Infertility - Low levels of thyroid hormone can interfere with ovulation

  • Birth defects - babies born to women with untreated thyroid disease have a higher risk of birth defects - intellectual and developmental problems


  • Eating healthy and small regular meals that will give you energy throughout the day is essential. There isn’t a specific diet for hypothyroidism, but emphasis is put on having meals around veggies, fruits, whole grains, lean protein and healthy fats.

  • Talk to your doctor about foods such as high fibre foods and supplements such as iron or calcium that can affect absorption of levothyroxine, before you attempt to take them.

  • Talk to your doctor about taking iodine supplements. Iodine is required to produce the thyroid hormone and a deficiency in it can cause hypothyroidism. Iodine is usually found in iodized salts and other foods such as cheese, soy sauce, saltwater fish, eggs, etc. Iodine supplements in the form of potassium iodide or sodium iodide or those containing kelp or spirulina are a good source of iodine.

  • Regular exercise is important to maintain a healthy weight, boost energy and decrease stress. Focus on aerobic exercises, strengthening and flexibility. Try to exercise for about 30 minutes a day, five times a week.

  • Manage your stress with meditation, deep breathing exercises, massages, yoga, etc.

  • Hypothyroidism can make you feel tired and drained throughout the day. Having a sleep schedule and sticking to it may help. Try to sleep for about seven to nine hours everyday regardless of the time you go to sleep.

  • Take medications as prescribed by the doctor. Do not miss dosages and make sure you have regular visits to the doctor for proper management.







The thyroid is a butterfly-shaped gland, that sits at the base of the neck, in front of the airpipe. One of its main functions is controlling metabolism1, [4]


The main thyroid diseases that have been classified include:

Hypothyroidism – when the thyroid is underactive and not functioning adequately, leading to a decrease in hormone production, such as the thyroid hormone. This is the most common form of thyroid dysfunction [2,2]

Hyperthyroidism – when the thyroid is overactive and produces too much thyroid hormone [3]

Thyroid nodules – abnormal lumps/growths on the thyroid gland [3]

Thyroiditis – inflammation of the thyroid gland [3]

Over-medication with thyroid hormone [3]


There are various causes of hypothyroidism (with subsequent decrease in thyroid hormone levels), including:

Iodine deficiency, as the thyroid gland needs iodine to produce its hormones, including thyroid hormone [4]

Auto-immune condition known as Hashimoto thyroiditis, where the body’s own defence system attacks the thyroid gland, damaging the gland, impacting its ability to function properly and produce thyroid hormone [6, 7]

Surgical removal of the thyroid gland

Radioiodine treatment of the thyroid gland (often used for treating hyperthyroidism of cancer of the thyroid gland)

Radiation therapy to the head or neck

Being born without a thyroid gland [8]

Disease to either the pituitary gland or hypothalamus in the brain, because the aforementioned organs stimulate the thyroid gland to function properly [2]

Postpartum thyroiditis – This is a condition that occurs in young mothers after giving birth and may include both hypothyroidism and hyperthyroidism.


Postpartum thyroiditis can be a temporary condition or it can develop into long-term hypothyroidism [6]



People with an underactive thyroid may experience the following: [2,6]

  • Lack of energy

  • Slow metabolism resulting in weight gain

  • Thinning hair

  • Hoarseness

  • Increased sensitivity to cold

  • Slow heart rate less than 60 beats per minute

  • Depression

  • Impaired memory

  • Pain, stiffness and swelling of muscles and joints

  • Dry, puffy, pale skin

If you experience some of the above signs and symptoms, consult your doctor.


Although anyone can develop hypothyroidism, the following may increase your risk: [3, 10]

  • Affects females more than males

  • History of an autoimmune condition

  • Family history of thyroid disease

  • Received radiation (neck) or radioactive iodine therapy

  • Thyroid surgery

  • Pregnancy


  • Diagnosing hypothyroidism is usually straightforward by means of a blood test, measuring the hormone thyrotropin (THS).

  • TSH is produced by your pituitary gland to signal your thyroid gland to release more or less thyroid hormone.

  • A TSH level within the normal range (0.4–2.5 mU/l) will exclude any significant malfunction of your thyroid gland.

  • If the TSH level is just above the upper range of normal (above 2.5 mU/l), it is possible that you may develop hypothyroidism in the future.

  • If the TSH level is elevated (above 4 mU/l), it is quite likely that you suffer from hypothyroidism, in which case more tests are now needed to confirm the diagnosis, assess the degree and determine the cause. [3]


Hypothyroidism is treated by means of thyroid hormone replacement therapy, replacing what the body cannot produce on its own. [11]

  • The thyroid pre-hormone levothyroxine is usually effective on its own in the treatment of hypothyroidism. [11]

  • In rare occasions levothyroxine needs to be combined with triiodothyronine (T3) in order to achieve optimal metabolic control. [6]


Depending on the cause, some cases would require thyroid hormone therapy for life (as with Hashimoto), yet other cases may only require short term thyroid hormone therapy (as with post-partum thyroiditis). Further: [3, 6]

  • Your doctor will establish the correct dose of thyroid hormone for you

  • Schedule regular check-ups with your doctor

  • Be compliant to medication therapy

  • With your hypothyroidism controlled, you will be able to live an entirely normal healthy life with a normal life span

A Word on Thyroid Function and Pregnancy

During pregnancy, the need for thyroid hormone will increase. Normally, a healthy thyroid gland will just simply respond to that need and produce more thyroid hormone from the amounts of iodine stored and supplied. However: [9, 10]

  • If the capacity of your thyroid gland to produce adequate amounts of thyroid hormone is compromised, additional thyroid hormone must be supplied externally

  • Pregnant women are at greater risk of developing hypothyroidism than the general population, as Oestrogens and other male and female hormones can affect the way your body handles thyroid hormones

  • New mothers also have a greater chance of developing a thyroid disorder within the first months after delivery, partly because a deregulated immune system may cause postpartum thyroiditis

  • Screening for thyroid disorders during early pregnancy and postpartum is therefore of utmost importance. [10]


Hyperthyroidism occurs for different reasons compared to hyperthyroidism:

The most common cause (up to 70% of all cases) is a disease of the immune system called Graves’ disease. Graves’ disease tends to run in families and occurs more frequently in young women. [3]


Symptoms usually vary, but may include: [3]

  • Weight loss

  • Insomnia

  • Irritability

  • Excessive sweating


Blood tests can confirm the diagnoses with ease and accuracy if it shows elevation in thyroid hormone T3 and/or T4. [3]


Treatment is aimed at reducing the over-production of thyroid hormones, and treatment options include the following: [3]

  • Anti-thyroid medication

  • Radioactive iodine treatment

  • Surgical removal of the thyroid gland or nodule


Thyroid nodules can also cause hyperthyroidism.3 Nodules in the thyroid gland are very common, and approximately 5% of them are malignant (thyroid cancer). [9, 10]

  • Therefore, nodules generally need further investigating by the doctor

  • If the nodule is producing excessive amounts of thyroid hormone then the person will have symptoms of hyperthyroidism [9,10]

  • Nobody is sure why people develop thyroid nodules, but a lack of dietary intake of iodine is thought to be a factor [10]

Please Note: This is an educational information leaflet only and should not be used for diagnosis. For more information on thyroid disorders, consult your healthcare professional.




  1. Gentile, J.M. [Internet]. 4 Lifestyle Tips for Hypothyroidism. America: Remedy Health Media LLC; [updated 2019; cited 2019 Aug 15]. Available from:

  2. Rodriguez, D. [Internet]. 8 Ways to live better when Diagnosed with Hypothyroidism. New York, US; [updated 2017 Oct 27; cited 2019 Aug 15]. Available from:

  3. Mayo Clinic Staff [Internet]. Hypothyroidism underactive thyroid). America: Mayo Clinic; [updated 2018 Dec 04; cited 2019 Aug 23]. Available from:

  4. Norman, J. [Internet]. Hypothyroidism: Overview. Causes and Symptoms. New Jersey: endocrineWeb; [updated 2019 Jul 10; cited 2019 Aug 23]. Available from:

  5. WebMD [Internet]. Hypothyroidism. America: WebMD LLC; [updated 2019 Aug 16; cited 2019 Aug 23]. Available from:

  6. Celiac Disease Foundation [Internet]. What is Celiac Disease?. America: Celiac Disease Foundation; [cited 2019 Aug 26]. Available from:

  7. Leonard, J. [Internet]. 12 signs and symptoms of hypothyroidism. United Kingdom: Healthline Media; [updated 2019 Feb 25; cited 2019 Sep 12]. Available from:

  8. Shamon, M. [Internet]. Diet and Weight Loss Tips for Thyroid Patients. America: verywell health; [updated 2019 Sep 04; cited 2019 Sep 12]. Available from:


From Causes of Thyroid Dysfunction material given in black in content:

1. American Thyroid Association. Thyroid Function Tests.

2005 Accessed March 2009.

2. American Thyroid Association. ATA Hypothyroidism
Booklet. Falls Church, VA 2003.

3. American Thyroid Association. Hyperthyroidism. 2005 Accessed March 2009.

4. Roberts CG, Ladenson PW. Hypothyroidism. Lancet.
2004; 363: 793–803.

5. Families online. Accessed March 2009.
6. American Association of Clinical Endocrinologists.
Hashimoto thyroiditis Accessed March 2009.

7. American Thyroid Association. Hypothyroidism. 2005 Accessed March 2009.

8. Bettendorf M. Thyroid disorders in children from birth to adolescence. Eur J Nucl Med Mol Imaging. 2002; 29
Suppl 2: S439–46.

9. American Thyroid Association. Cancer of the thyroid. Accessed March 2009.
10. American Thyroid Association. Thyroid nodules. 2005 Accessed March 2009.

References from Balancing Your Thyroid Gland Given in red in content

1. Khan A, Muzaffar M, Khan A et al. Thyroid Disorders, Etiology and

Prevalence. J Med Sci. 2002;2:89-94.

2. Canaris GJ, Manowitz NR, Mayor G et al. The Colorado thyroid disease
prevalence study. Arch Intern Med. 2000;160:526-34.

3. American Thyroid Association. ATA Hypothyroidism Booklet. Falls
Church, VA 2003

4. American Thyroid Association. Thyroid Function Tests. 2005
Accessed March 2009

5. American Thyroid Association. Hyperthyroidism. 2005

Accessed March 2009.


6. Ladenson PW; Lancet Vol. 363 No 9411, p 793-803
7. Bettendorf M. Thyroid disorders in children from birth to adolescence.
Eur J Nucl Med Mol Imaging. 2002; 29 Suppl 2: S439–46

8. WHO. Iodine defi ciency in 2007: Global progress since 2003 Accessed November 2011

9. De Groot LJ, Stagnaro-Green A, Vigersky R. Patient guide to the
management of maternal hyperthyroidism before, during and after

pregnancy. The Hormone Foundation. 2007

10. Fast Facts For Your Health. Thyroid Disease and Women. National
Women’s Health Resource Center. Red Bank, NJ.2006

11. SPC; packaging leaflet of Levothyroxine product

Hypothyroidism Fig 2 [8].png
Hypothyroidism Fig1 [7].jpg
Thyroid Conditions
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