Thyroid problems have become increasingly common, and it is not unusual for doctors to ask patients about a history of thyroid disease or recommend a thyroid test while evaluating seemingly unrelated symptoms such as fever, fatigue, weight changes, menstrual problems or reproductive issues. But why is the thyroid so important?

To understand the condition, its symptoms, impact on pregnancy and treatment options, we spoke toDr. Meghanad Meher of IMS & SUM Hospital, Bhubaneswar, who explained the role of the thyroid and why maintaining healthy thyroid function is important.

What is the thyroid?

According to Dr. Meher, the thyroid is like a control centre for several important functions of the body. It is a small, butterfly-shaped gland located at the front of the neck. The gland produces the hormones T3 and T4, which play a major role in regulating metabolism, energy use, heart rate, body temperature and several other bodily functions.

The two major types of thyroid disorders are hypothyroidism, in which the thyroid produces insufficient hormones, and hyperthyroidism, in which it produces excessive hormones.

Hypothyroidism vs Hyperthyroidism

People with hypothyroidism may experience persistent tiredness and weakness, unexplained weight gain, increased sensitivity to cold, dry skin, thinning or coarse hair, constipation, a low or depressed mood, memory difficulties and a slower heartbeat. Swelling or puffiness of the face and body may also occur, particularly in more severe cases.

Hyperthyroidism, on the other hand, can cause symptoms such as palpitations, unexplained weight loss, frequent bowel movements or diarrhoea, anxiety, nervousness, trembling, excessive sweating and heat intolerance. Muscle weakness and tiredness may also occur.

Women with thyroid disorders can additionally experience menstrual irregularities and fertility-related problems.

What causes thyroid disorders?

Thyroid problems can develop for several reasons. Common causes include autoimmune disorders such as Hashimoto's disease and Graves' disease, abnormalities in iodine intake, inflammation of the thyroid gland, previous thyroid surgery or radiation treatment, and certain medicines.

Some medications, including lithium and amiodarone, can also affect thyroid function.

Why are women more likely to develop thyroid problems?

According to Dr. Meher, women are more susceptible to thyroid disorders, particularly autoimmune thyroid diseases. Hormonal changes associated with different stages of a woman's life can also influence thyroid function.

This is one reason thyroid evaluation is often considered when women present with menstrual irregularities, fertility problems or pregnancy-related concerns.

How can thyroid disorders affect pregnancy?

Thyroid hormones play an important role in pregnancy and fetal development. Untreated thyroid disorders can increase the risk of complications, including miscarriage, premature birth and low birth weight.

Maternal thyroid hormone abnormalities can also affect the developing baby's brain and nervous system. Therefore, women with known thyroid disease should remain under appropriate medical supervision during pregnancy.

Thyroid medication should not be stopped during pregnancy without medical advice. Treatment is generally continued or adjusted by the treating doctor according to the woman's thyroid function and pregnancy status.

Importantly, thyroid targets during pregnancy are trimester-specific, so a single TSH target should not be applied to every pregnant woman. The treating obstetrician or endocrinologist should determine the appropriate target.

Why can thyroid problems cause weight gain or weight loss?

The thyroid influences the body's basal metabolic rate (BMR)—the amount of energy the body uses at rest.

In hypothyroidism, a lower metabolic rate can contribute to weight gain, while fluid and salt retention may cause additional puffiness. In hyperthyroidism, the increased metabolic rate can result in weight loss, even when appetite remains normal or increases.

However, thyroid disease is not the only cause of weight gain or weight loss, and unexplained changes in weight should be evaluated by a doctor.

When is thyroid surgery required?

Thyroid surgery, or thyroidectomy, may be recommended in selected cases. These can include suspected or confirmed thyroid cancer, a large goitre that causes difficulty breathing or swallowing, or certain cases of hyperthyroidism that cannot be adequately controlled with other treatments.

The decision for surgery depends on the underlying condition, test results, symptoms and the patient's overall health.

What happens if thyroid disease is left untreated?

Untreated thyroid disorders can affect multiple systems of the body. Depending on whether a person has hypothyroidism or hyperthyroidism, complications can involve the heart and blood vessels, blood pressure, skin and hair, metabolism and reproductive health.

Thyroid dysfunction may also be associated with abnormalities in cholesterol levels and can complicate conditions such as diabetes and polycystic ovary syndrome (PCOS).

Diet and lifestyle

Dr. Meher recommends maintaining a balanced, whole-food diet and ensuring adequate—but not excessive-iodine intake. Selenium is also an important nutrient for normal thyroid function.

Regular physical activity, such as around 30 minutes of brisk walking a day, can support overall health. People taking thyroid medication should follow their doctor's instructions carefully; many thyroid medicines are taken on an empty stomach because food and certain supplements can interfere with absorption.

Stress management, adequate sleep and regular medical follow-up can also contribute to overall well-being.

Why is thyroid testing so common?

The thyroid affects several systems simultaneously, and its symptoms can overlap with many other conditions. Changes in weight, energy levels, heart rate, bowel habits, mood, menstrual cycles and fertility can sometimes be linked to abnormal thyroid function.

That is why doctors may consider thyroid testing when a patient's symptoms or medical history suggest a possible thyroid disorder. A thyroid test-often beginning with TSH, with additional tests such as free T4 when appropriate-can help determine whether the thyroid is functioning normally.

Thyroid disorders are treatable, but the right diagnosis and treatment plan should always be determined by a qualified healthcare professional.