Hypothyroidism – FAQ


  1. What is hypothyroidism?
    A condition in which the thyroid gland, which is located in the neck, does not make sufficient thyroid hormone to meet the body’s requirements. Hypothyroidism is often referred to as an “underactive thyroid gland”.


  1. What causes hypothyroidism?
    Almost all hypothyroidism is caused by autoimmune disease. In this condition, the immune system goes awry and begins to destroy the thyroid gland. This is a gradual process. It is not usually associated with thyroid gland discomfort, but may cause the gland to enlarge or shrink in size. The autoimmune disease is restricted to the thyroid gland; consequently, treatment with thyroid hormone (also known as L-thyroxine) completely corrects the condition. Another important cause of hypothyroidism is the treatment of hyperthyroidism (an overactive thyroid gland), which often causes the thyroid gland to fail after a number of years.


  1. How common is hypothyroidism?
    Hypothyroidism is relatively common. It affects between 1 in 100 to 3 in 100 women of child-bearing age. It is more common in women than in men, and it becomes more common with age. Hypothyroidism occurs in up to 5 to 10 percent of older women.


  1. What are the symptoms of hypothyroidism?
    Hypothyroidism slows metabolism and affects essentially every system in the body. Symptoms include generalized fatigue, weight gain, thinning (brittle) hair, dry scaly skin, thin nails that break easily, constipation, irregular cycles, heavy bleeding during cycles, pain in muscles, and slow heart rate. You may notice changes in behavior, such as decreased ability to concentrate, reading and calculating are more difficult, and you may experience decreased interest in personal relationships or work and feel sleepy all the time. Hypothyroidism can cause or worsen depression.
  2. How is hypothyroidism tested?
    A blood test is performed. It measures your thyroid hormone (thyroxine or T4) and TSH (Thyroid-stimulating hormone) levels.
  3. How are the thyroid test results interpreted?
    An elevation of TSH is a very sensitive index of reduced thyroid function. Hypothyroidism is characterized by a TSH level that is above the normal range and a thyroxine level that is below or at the low end of the normal range (everyone’s set point is a little different). Your physician can assist in the interpretation of these results, or you may wish to see an Endocrinologist who specializes in hormonal disorders.

    1. What is the treatment for hypothyroidism? Are there any side effects?
      A drug called L-Thyroxine (L-T4) is used to replace the missing thyroid hormone. Some preparations also include a second form of thyroid hormone, tri-iodothyronine (L-T3). These hormones are chemically identical to those made by your own thyroid gland. Consequently, when the correct doses are prescribed and restore your metabolism to normal, the treatment is not accompanied by side effects. The medication is in the form of a tablet, taken once a day. Taking too much thyroid hormone will, of course, speed up metabolism and can cause rapid or irregular heart rate and loss of calcium from the bone. However, excess thyroid hormone levels are unlikely to occur when the treatment is carefully prescribed and monitored.
  4. Is hypothyroidism curable?
    The underlying cause of hypothyroidism (autoimmune thyroiditis) is not reversible. However, the consequences of hypothyroidism can be treated very effectively by taking thyroid hormone replacement medication. The dose of thyroid hormone can be carefully regulated so that your body’s metabolism is restored to normal. You should have your blood tested at least once a year, or more often if necessary, to be certain that the thyroid hormone dose you are taking is satisfactory.


  1. Will I be on the thyroid hormone medication for the rest of my life?
    It is probable that you will require thyroxine replacement for the rest of your life.


  1. Will I have to change my lifestyle because of hypothyroidism?
    Aside from taking a daily tablet, containing L-thyroxine, you should not have to change your lifestyle.


  1. Is there a way to prevent hypothyroidism?
    Iodine deficiency can cause hypothyroidism but this is very unlikely in India since universal salt iodisation program. There are no other preventative measures you can take to avoid hypothyroidism.


  1. Is hypothyroidism hereditary?
    Hypothyroidism tends to “run in families”. If you have a history of either hypothyroidism, or paradoxically, hyperthyroidism in your family, it increases the chance that you may someday develop the condition. However, except for a few rare disorders, hypothyroidism is not transmitted in a typical dominant or recessive manner. If you have a strong family history of underactive or overactive thyroid disease, you should mention this to your endocrinologist.
  2. I was diagnosed with hyperthyroidism (Graves’ disease) and treated with radioactive iodine. Am I a candidate for hypothyroidism?
    Many, approximately 50% of patients treated with radioiodine, and many treated with antithyroid drugs, eventually develop hypothyroidism and should be tested at about yearly intervals.
  3. I know that I have hypothyroidism. Will my hormone dose change because of pregnancy?
    A: Thyroid hormone requirements increase, on average, by about 25% during pregnancy. Therefore, thyroid function tests should be checked during pregnancy and thyroid hormone replacement should be adjusted to maintain the TSH level in the normal, or low-normal range (to mimic the normal physiology of pregnancy).
  4. I am planning to become pregnant. Should I be tested for hypothyroidism?
    If you have symptoms of hypothyroidism, or if others in your family have thyroid disease, testing is necessary. If you have any concerns or questions about the possibility of having hypothyroidism, consult your endocrinologist.
  5. I am pregnant now. Should I ask my obstetrician to test me for hypothyroidism?
    At present, thyroid testing is not routinely performed during pregnancy. However, you should discuss any symptoms or concerns with your endocrinologist, and mention any personal or family history of thyroid disease. Recent studies suggest that early diagnosis and treatment of maternal hypothyroidism during pregnancy is beneficial for the developing baby.


  1. I am tired all the time, but thought that was just due to pregnancy. How do I know the difference?
    If you experience the symptoms listed above in addition to the fatigue, you should alert your endocrinologist who can perform blood tests of thyroid function.


  1. How will treatment effect my pregnancy (fetus)?
    A: Thyroid hormone is important for your health and for the development of your fetus. The treatment is safe and essential for both mother and baby.


  1. Why does my hypothyroidism impact the baby?
    Some of the mother’s thyroid hormone crosses the placenta to provide a hormone supply to the baby until its own thyroid gland starts to function especially in first three months. Evidence is accumulating that your thyroid hormone plays a role in the early development of the fetus, particularly brain development.


  1. Do I need to seek testing for my baby prior to birth? What tests should I request at birth?
    Your baby does not need to best tested before birth as long as the pregnancy is proceeding normally. You should consult your obstetrician about this. In the U.S. and Canada, all babies are routinely screened for a low thyroid level as part of the newborn screening program. This test will be performed prior to leaving the hospital. However, you should tell your pediatrician that you have hypothyroidism. Your pediatrician will decide whether additional testing of your baby is necessary after birth.


  1. If I am being treated for hypothyroidism, can I nurse my baby?
    Very small amounts of L-thyroxine appear breast milk, but will not adversely affect your baby. However, when taking any medication, consult your endocrinologist before you nurse.
  2. Does thyroid hormone interact with any other medications or dietary supplements that I am taking?
    In general, no special dietary restrictions are necessary and thyroid hormone interacts with few other medicines. One exception is the use of iron tablets, which can interfere with the absorption of thyroid hormone. If you are taking iron tablets or prenatal vitamins with iron, they should be taken at a different time of day from the thyroid tablet. And, you may need to have thyroid hormone blood levels checked to assure that the dose is correct. You should always review all of your medications with your endocrinologist.
  3. Will thyroid hormone treatment impact my fertility and/or future pregnancies?
    Thyroid hormone treatment does not adversely affect fertility. In fact, treatment restores fertility in some patients with hypothyroidism.
  4. I was diagnosed with hyperthyroidism (Graves’ disease) and treated with radioactive iodine. Am I a candidate for hypothyroidism?
    Many, approximately 50% of patients treated with radioiodine, and many treated with antithyroid drugs, eventually develop hypothyroidism and should be tested at about yearly intervals.
  5. I was diagnosed with Graves’ Disease. Will the radioactive iodine treatment for hyperthyroidism affect my ability to get pregnant, and/or have a negative impact on my pregnancy?
    The amount of radiation exposure to your ovaries during treatment is small. There is no evidence that the children of mothers who have been treated with radioactive iodide before pregnancy have an increased incidence of abnormalities. However, most endocrinologists recommend that you wait at least six months after treatment before becoming pregnant. Treatment during pregnancy, however, can affect the baby’s thyroid gland. You should be certain that you are not pregnant prior to treatment with radioactive iodine.


  1. How is hypothyroidism treated in the newborn?
    When hypothyroidism is detected in the newborn, they are treated with L-thyroxine, which is given orally by mashing the pill and placing it into milk. If treated soon after delivery, the child will usually achieve normal intelligence.


  1. If I have hypothyroidism during pregnancy, will my baby develop hypothyroidism?
    Maternal hypothyroidism does not cause hypothyroidism in baby. However, you should be treated with thyroid hormone to prevent milder intellectual problems in the baby.