Underactive Thyroid: Reasons, Treatment, Signs, And More

The picture shows a girl with her hand on her neck

When the thyroid hormone level is decreased in the body, causes underactive thyroid, also known as hypothyroidism.

According to the studies, there are about 42 million people suffer from a thyroid issue in India, and hypothyroidism is more common than hyperthyroidism.

It is an endocrine disease means (when produced hormones do not work properly).

The thyroid gland is a butterfly-shaped organ located in the front lower part of the neck, that produces the hormones.

It produces 2 hormones called T3 and T4, which travel through the bloodstream and affect every part of our body, from mental and physical health.

NOTE: If it rises in an adult then is called hypothyroidism, but it is formed by birth, or congenital, then is called cretinism.

Women are more prone to hypothyroidism than men, however, old age especially above 60 is more chance of getting it, but it can happen at any age.

Its early diagnosis can control it to a great extent, and adopting a healthy lifestyle can save you from the danger of getting it.

1. Symptoms

The signs and symptoms of underactive thyroid are varied from person to person.

Here are the most common symptoms of hypothyroidism in adults. which include:

Symptoms of underactive thyroid in babies

If a baby has overactive thyroid called congenital hypothyroidism, then these symptoms may occur are include:

  • Constipation
  • Hoarse cry
  • very slow growth
  • low muscle tone
  • very less eating
  • Jaundice
  • Stomach bloating
  • cold hand and feet
  • swollen tongue

Talk to your family doctor, about the condition, they will perform some tests to determine if you have hypothyroidism or some other disease.

2. Reason

There are most common reasons for an underactive thyroid are:

Auto-immune disorder

If thyroiditis means – (thyroid gland inflammation) is an auto-immune disorder. In this, the body produces antibodies that attack the thyroid gland.

Thyroiditis disorder may be caused by viral infection.

Patients having previous hypothyroidism are could be the reason for it to happen again.

Check Out – Immune System: Disorder, Response, And More

Radiation therapy

If someone has neck and head cancer, like lymphoma and they treat with radiation therapy, which triggers thyroid gland, causes swelling.

Swelling in the thyroid leads to unstable T3 and T4 hormones, which also make it more difficult for the gland to produce hormones.


Certain medicines that contain lithium, and iodine compounds also cause hypothyroidism.

However, medicines to treat heart diseases, and cancer can sometimes affect the production of thyroid hormones.

Iodine deficiency

If there is a lack of iodine deficiency in the body, then there is a chance that there will be goiter (a condition where swelling happen of the thyroid gland)

Problem with thyroid at birth

This may occur in children, by birth called congenital hypothyroidism, where the thyroid gland did not develop correctly or does not work properly.

In India, the prevalence of congenital hypothyroidism is 1 in 2640 based on the 1998 study (2).

3. Underactive thyroid Effect in pregnancy

The fetas inside the women, start secretion this thyroid hormone only at the end of the 3rd month and is fully functional by the 5th month.

Therefore, the baby is dependent on the mother for the thyroid hormone, until that stage.

NOTE: This thyroid is very important for the development of the brain and spinal cord of the baby.

If women have hypothyroidism and take medication, the pregnancy should be planned beforehand, If remain untreated it can cause:

How can a doctor diagnose it?

Unfortunately, it can’t be diagnosed only based on symptoms, some of the symptoms of hypothyroidism are similar to the symptoms of pregnancy like:

NOTE: That is why, as soon as your pregnancy comes positive, it is vital to do a blood test called TSH (thyroid-stimulating hormone).

If someone is on thyronorm 50 mg before or during pregnancy, it may be increased to about 62.5 or 75 according to the thyroid levels.

And it usually continued throughout the pregnancy, can be stopped depending on the TSH levels after the delivery.

4. Types

Primary hypothyroidism occurs when the problem is with the thyroid gland itself.

Secondary hypothyroidism occurs when other problems interfere with the thyroid function for example –

There are main 5 secondary types of hypothyroidism such as:

Primary hypothyroidism

If there is dysfunction of the thyroid gland, then is called primary or thyroidal hypothyroidism.

Central hypothyroidism

Disfunction of hypothalamus and pituitary gland (secrete a hormone called TSH, which stimulates the thyroid gland to release thyroid hormone).

Pituitary hypothyroidism

In this, if abnormality happens only in the pituitary gland, then is called pituitary or secondary hypothyroidism.

Hypothalamic hypothyroidism

The Hypothalamic is a gland in your brain that controls your hormone system.

If dysfunction only happens with the hypothalamic then is also called tertiary hypothyroidism.


If the baby has had hypothyroidism since birth, then is called cretinism or congenital hypothyroidism.

5. Who is more at risk of this?

Factors that increase the risk of getting it. they include:

  • Women have more chances of getting it, compared to men
  • If someone in family members has an autoimmune disease, then you may be at increased risk of getting it.
  • White and asian peoples
  • Older people, especially obove 60
  • Biploar disorder
  • Turner syndrome
  • Patients having previous hypothyroidism are more risk of this
  • If a lady were pregnant in the past 6 months (2).
  • Family history of thyroid disorder
  • Surgery

6. TSH level range

NOTE: If the TSH level is below 0.5 mU/L, then is suggested that the thyroid is overactive (hyperthyroidism)

The normal TSH range recommended is from (0.3/0.5 to 3.0/5.0).

If the TSH level is above 5.0 then is suggested that the thyroid is underactive (hypothyroidism)

7. Diagnose

If the doctor sees any symptoms of hypothyroidism, the doctor may do some tests, which include:

Serum TSH

In this, the doctor checked or monitored T3 (Triiodothyronine) and T4 (Thyroxine) levels, which to easily identify if the patient has hypothyroidism or not.

If its level comes less, then it means the patient has hypothyroidism.

However, some people may have increased TSH levels while having normal T4 levels this is called subclinical (mild) hypothyroidism (3)

It is believed to be an early stage of hypothyroidism.

Thyroid scanning

In this, doctors use radioisotope scans, to find out whether there are cancer cells in your thyroid gland or not.

Also, to check for nodules or inflammation.

The doctor also performs a physical exam and history.

8. Treatment

Medical ways

If T3 and T4 thyroid hormones are absent in the body, then the doctor replaces the missing hormones by restoring normal metabolic activity.

In replacement, the doctor provides two hormones are – Synthroid and Levothroid.

If there is metabolic dysfunction then there is a dehydration problem raised, then doctors also provide fluid, but with precautions.

The specialist may also give patients hormonal therapy for example – In menstrual abnormality.

The doctor also provides some medication every day, but reducing pills amount can again trigger your thyroid hormones.

NOTE: some pills may interact with other medicines, herbs, and supplements, so talk to your doctor, before taking any pill, to prevent possible side effects.

NOTE: Make sure you get regular blood tests done to check thyroid levels. And take medicine from time to time.

Most doctors recommend taking the pills in the morning before eating, more information talks to your doctor.

An underactive thyroid can be completely controlled with medicines, however, it can cause some side effects such as:

  • atrial fibrillation
  • Increased sweating
  • Fatigue
  • headache
  • Tiredness
  • Osteoporosis
  • feel sad
  • Lack of sleep

Natural way

A healthy lifestyle and a good diet play an important role in managing or preventing the risk of any disease.

Diet – a proper diet such as a limited amount of iodine is good for the thyroid gland to work properly.

NOTE: Pregnant ladies need more foods for the proper development of a baby, consult the doctor that how much foods intake is enough for both.

Check Out – 8 Super Ideal Foods That Are Eaten During Pregnancy

Healthy lifestyleExercises at least 1 hour daily, whether is running, jogging, yoga, cycling, gym, etc can improve overall health.

Here are some ways that help you to live a healthy lifestyle such as:

  • Avoid smoking, and excessive alcohol
  • Eat a healthy diet, and never skip meals, but fasting is different from this
  • Take enough sleep daily at least 7 to 8.
  • Trust yourself, which improves self-esteem or confidence.
  • Live happy life
  • Do not go with bad things, always go with good things.

Check Out – Foods To Eat And Avoid For Overactive Thyroid Patient

9. Complications

An untreated underactive thyroid may cause complications such as:

  • Rarely seen myxedema coma, it is an extreme form of hypothyroidism, where body function slowly leads to life-threatening.
    • It require quick medical attention
  • Increase in the level of cholesterol, so test your cholesterol level, because it may also lead to a heart attack.

Other complications that may be seen in patients of an underactive thyroid include:

  • Goiter
  • Thyroid hormone may distrub female hormones leads infertility
  • Joint pain
  • Mental health issues like – low concentration, decrease interest in working, low mood, etc
  • Heart problem
  • Obesity changes your appetite, and metabolism work also slows down, due to which it becomes difficult to lose weight.
  • Nerve injury
  • Sleep apnea


If you see these symptoms or any other discomfort then talk to your doctor and early diagnosis is the best way to prevent complications.

An underactive thyroid is caused due to many reasons, When the thyroid hormone level is decreased in the body, causes underactive thyroid.


Hello, I'm Sahil bisht, I am a Mechanical engineer, As well as, aspiring blogger with an obsession for health. This blog delicate to people who want to learn in health.

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