What Are Thyroid Symptoms in Babies? Early Signs, Diagnosis, and Treatment

Thyroid disorders in babies often go unnoticed in the early weeks of life. As you all know, the thyroid gland, located at the front of the neck, produces hormones essential for brain development, growth, and metabolic regulation.  

Congenital hypothyroidism is a condition present from birth that affects a baby’s ability to produce enough thyroid hormones. Although rare, its consequences can be drastic if it is undiagnosed. In this article, we will understand what the common thyroid symptoms in babies are, the causes, and the treatment options. 

What are the common thyroid symptoms in babies? 

Symptoms of congenital hypothyroidism in babies don’t appear immediately. They can develop gradually over the first few weeks. Some common symptoms are:  

• Poor feeding or difficulty sucking milk 
• Excessive sleepiness, appearing drowsy most of the time 
• Low activity levels or lack of alertness 
• Constipation or infrequent bowel movements 
• Prolonged jaundice that does not resolve within a normal time 
• A large tongue, sometimes sticking out of the mouth 
• Puffy face with swelling around the eyes 
• Dry, cool skin with a rough texture 
• Hoarse cry, sounding deep or weak 
• Large soft spot (fontanelle) on top of the head 
• Weak muscle tone leading to floppy limbs 

While many babies show only subtle signs initially. Ignoring these signs can affect the baby's growth and brain development.  

What causes congenital hypothyroidism? 

There are several causes of congenital hypothyroidism: 

Thyroid dysgenesis

 The thyroid gland is absent (agenesis), underdeveloped (hypoplasia), or located in an abnormal position, such as the tongue base (ectopic thyroid). 

Dyshormonogenesis 

The gland is present but doesn’t produce hormones efficiently. It happens due to enzyme deficiencies affecting thyroid hormone synthesis. 

Iodine deficiency

Inadequate iodine intake during pregnancy can interfere with hormone production. 

Genetic mutations 

Inherited mutations affecting thyroid development or hormone synthesis pathways cause congenital hypothyroidism. 

Maternal antibodies

This is a rare case where antibodies from the mother may cross the placenta and block the baby’s thyroid function temporarily. 

How is thyroid diagnosed in babies? 

Diagnosis of congenital hypothyroidism relies on early screening. Routine screening for congenital hypothyroidism is done using cord blood TSH or after 48 to 72 hours after birth using a heel-prick blood sample. The test assesses: 

• Thyroid-Stimulating Hormone (TSH): High levels suggest the gland is not producing adequate hormone. 
• Thyroxine (T4): Low levels confirm reduced hormone production. 

If screening results are abnormal, the confirmatory blood tests are advised immediately. Additional diagnostic methods include: 

• Thyroid ultrasound: Checks the presence, size, and structure of the gland in the neck. 
• Radionuclide thyroid scan: Determines the location and function in suspected ectopic thyroid cases. 
• Genetic testing: In selected cases with suspected hereditary causes or associated anomalies. 

Timely diagnosis is crucial because untreated congenital hypothyroidism can lead to permanent intellectual disability and growth failure. 

Treatment for congenital hypothyroidism 

To cure this, daily thyroid hormone replacement therapy is suggested to normalize hormone levels. Babies are usually prescribed levothyroxine, a synthetic form of thyroxine (T4), in tablet form. The dose is adjusted based on: 

• Age and weight of the baby 
• Blood test results assessing T4 and TSH levels 

Medication is crushed and given in small amounts of milk or water. Avoid soya-based formula or calcium supplements as they interfere with absorption. Regular follow-up with a paediatric endocrinologist ensures that growth and development milestones are met. If the treatment begins in the first 2 weeks of life, the baby will have normal physical and cognitive abilities. 

How to prevent thyroid problems in babies? 

Preventing congenital hypothyroidism entirely is not possible in many cases, as it happens due to structural or genetic factors beyond your control. However, certain preventive measures support maternal and foetal thyroid health: 

• Take adequate iodine during pregnancy, either through iodised salt or supplements, if advised by the doctor. 
• Go for regular check-ups for early identification of maternal thyroid issues. 

Final Thoughts 

Thyroid symptoms in babies can be mild, but they carry significant long-term risks if left untreated. Hence, it is important to recognize the early signs, understand the causes, and ensure timely diagnosis and treatment. It will protect your baby from any growth delays and intellectual challenges. 

If you notice any of these symptoms in your baby or wish to consult a paediatric endocrinologist for evaluation, Hinduja Hospital Mahim offers specialised diagnostic and treatment services to support your child’s health and development journey. 

Frequently Asked Question (FAQs) 

How to reduce thyroid in kids? 

For hyperthyroidism (overactive thyroid), doctors prescribe anti-thyroid medicine such as methimazole to lower hormone levels. Sometimes beta-blockers are also used to control symptoms like a fast heartbeat until hormone levels become normal. Treatment usually continues for at least two years under medical supervision. 

What does the thyroid do in a child? 

The thyroid gland produces hormones that control growth, brain development, and metabolism. It helps regulate body temperature, energy levels, and how quickly the body uses food for energy. 

Is thyroid curable for babies? 

Congenital hypothyroidism (underactive thyroid at birth) cannot be reversed but is effectively managed with daily thyroid hormone medicine. Babies on proper treatment grow and develop normally. Hyperthyroidism in children can sometimes be cured with medicines, surgery, or radioactive iodine therapy, depending on the cause and severity. 

Which food is good for thyroid health? 

Foods beneficial for thyroid health include: 

• Seafood (fish, shrimp, seaweed) – rich in iodine. 
• Dairy products and eggs provide iodine and selenium. 
• Brazil nuts – high in selenium. 
• Sunflower seeds contain selenium and other minerals. 
• Foods with omega-3 fatty acids (like fish) and antioxidants support overall hormone balance.