Hypothyroidism, also called low or underactive thyroid, is a relatively common condition that develops when your thyroid — a butterfly-shaped gland located at the bottom-front of your neck — doesn't produce enough hormones.
Causes of hypothyroidism include thyroid surgery, inflammation in the thyroid from autoimmune disease (increased likelihood if you have a family history of the disease), iodine deficiency, or taking certain kinds of medication.
Anyone can develop hypothyroidism, but if you're a woman older than 60, you're most at risk of low thyroid levels. In fact, women in general are 5 to 8 times more likely to develop thyroid disease.
Studies have suggested ethnicity may also affect your chances of developing hypothyroidism. For example, research has suggested that white people are more likely than Black people and Asian American and Pacific Islanders to develop Hashimoto's thyroiditis, the most common cause of hypothyroidism in the United States.
Thyroid hormones affect more than a few body functions and therefore can lead to a range of symptoms that can vary by age group.
These are the most common symptoms you may have if you have an underactive thyroid gland.
Symptoms of Hypothyroidism in Adults
The most common hypothyroid symptoms are fatigue, cold intolerance, constipation, slower metabolism, and dry skin, while more surprising signs may be a slower heart rate, joint and muscle pain, and dry or puffy skin, says Gregory Dodell, MD, an assistant clinical professor of medicine, endocrinology, diabetes, and bone disease at the Icahn School of Medicine at Mount Sinai in New York City. Some people might experience one symptom but not the others. Adults with hypothyroidism may have any of the following signs and symptoms:
Babies born without a thyroid gland will develop hypothyroidism while those born with a dysfunctional thyroid gland may develop the condition.
Thyroid function is typically screened at birth. Babies may not immediately have signs or symptoms of the condition, but when they do, they include:
Growth abnormalities
Yellowed whites of eyes or skin (jaundice)
Puffy skin
Constant sleepiness
Constipation
Signs of Hypothyroidism in Children and Teenagers
Like infants, children and teens are also at risk of hypothyroidism. Often, symptoms in this age group mimic those of adults.
In addition to the symptoms that occur in adults, signs of hypothyroidism in this age group include:
Cognitive delays
Short stature
Late development of permanent teeth
Delayed puberty
Weight Gain Is Often One of the First Signs of Hypothyroidism
Gradual weight gain is perhaps one of the first noticeable signs of hypothyroidism. This is related to a slower than normal metabolism. You may find losing weight more difficult, or perhaps you gain weight despite diet and exercise. On top of that, you may also feel bloated from hypothyroid-related constipation.
Fatigue That Persists May Signal Hypothyroidism
Excessive fatigue is another common symptom of hypothyroidism. You may feel extremely tired all the time, no matter how much sleep you get.
Habitual daytime naps or a constant need for caffeine may also be signs of excessive fatigue related to this condition (unfortunately, these practices can also make it more difficult to sleep at night).
Reproductive Changes in Women Could Mean You Have Hypothyroidism
Women are at an increased risk for developing thyroid disease. Women are also more likely to develop thyroid conditions after pregnancy and following menopause.
"Women may experience a change in their menstrual cycle if their thyroid function is off," says Dr. Dodell. Not only might you experience irregularities in your cycle, but hypothyroidism may also cause periods that are much heavier than normal.
Women who are trying to conceive may have difficulties getting pregnant. "Therefore, women who are trying to get pregnant or are planning to try and get pregnant in the near future should have their thyroid levels checked," Dodell explains. "We also monitor women who are being treated for hypothyroidism closely during pregnancy, since the dose of medication may need to be adjusted."
A slowed-down metabolism from hypothyroidism may also lower your body heat. This can make you more cold intolerant.
Depression and Hypothyroidism Are Comorbidities
A lack of adequate thyroid hormones can make you feel unusually depressed. Aside from feeling depressed, forgetfulness is also common in people with hypothyroidism.
If left untreated, hypothyroidism can lead to the following issues, according to Mayo Clinic:
Goiter Hypothyroidism can cause the thyroid gland to become larger, which is known as a goiter. If it's large, it may cause swallowing or breathing problems.
Cardiovascular Disease Hypothyroidism can lead to a higher risk of heart disease and heart failure. People with an underactive thyroid tend to develop high levels of low-density lipoprotein (LDL) cholesterol — the "bad" cholesterol.
Peripheral Neuropathy Prolonged and untreated hypothyroidism can damage the peripheral nerves, which carry information from the brain and spinal cord to the rest of the body. Peripheral neuropathy may cause pain, numbness, and tingling in your arms and legs.
Infertility Hypothyroidism can interfere with ovulation, affecting fertility.
Birth Defects Babies born to people with untreated thyroid disease may have a higher risk of birth defects compared with babies born to mothers who do not have thyroid disease.
As a rule of thumb, Dodell suggests getting screened for hypothyroidism if you notice any of the signs and symptoms listed above. If you're experiencing unexplained weight gain and persistently feeling tired for no known reason, it's a particularly good idea to check in with your healthcare provider.
The best way your doctor can determine if you have hypothyroidism is through a blood test.
An elevated thyroid stimulating hormone or low levels of thyroid hormones, including free T4, total T3, or free T3, may also signal hypothyroidism. A physical exam or an imaging scan may also be used to diagnose this condition.
"If someone becomes significantly hypothyroid, they may have a slow heart rate or swelling or pain in their joints, elevated cholesterol, and muscle weakness," warns Dodell. "Since screening for hypothyroidism is common these days, and the majority of people will get checked if early signs develop, hopefully treatment is started prior to severe symptoms developing."
If you're persistently feeling fatigued or experiencing unexplained weight gain along with other symptoms like cold intolerance and depression, consider getting screened for hypothyroidism by your healthcare provider.
Left untreated, hypothyroidism can lead to serious complications like goiter, cardiovascular disease, and even infertility, so early diagnosis and treatment are important for managing potential risks.
While the condition is more common in women, especially those over 60, anyone experiencing these symptoms should consider a blood test to check thyroid levels.
Though some symptoms can overlap with less serious conditions or other health issues, they can also indicate the need for medical attention, particularly severe fatigue or significant changes in weight.
