About Congenital Hypothyroidism

Congenital hypothyroidism, a relatively uncommon yet critical condition, has a significant impact on the health and development of newborns.

This condition, which affects infants from birth, can have profound and lifelong implications if left undiagnosed and untreated. In this blog, we explore congenital hypothyroidism, its causes, diagnosis, and treatment.

Join us as we shed light on this often-overlooked aspect of neonatal health and discover how early intervention can make a world of difference in the lives of these tiny, yet resilient, individuals.pediatric hypothyroidism

What is Congenital Hypothyroidism?

Congenital hypothyroidism is a critical thyroid disorder present from birth that affects 1/2000 to 1/4000 births. The thyroid gland, a butterfly-shaped organ located in the neck, plays a crucial role in regulating the body's metabolism. It produces hormones, mainly thyroxine (T4) and triiodothyronine (T3), which influence the functioning of almost every cell in the body. These hormones play a role in metabolism and in an infant/toddler are important for neurocognitive development.

In the case of congenital hypothyroidism, there is a deficiency in the production of these vital hormones, which can lead to a wide range of developmental and health issues if left unaddressed.

Unlike other thyroid conditions that may develop later in life, this condition is present from birth and requires prompt identification and treatment, as early intervention is key to preventing irreversible cognitive and physical impairments.

Causes of Congenital Hypothyroidism

The majority of congenital hypothyroidism cases are due to improper formation of the thyroid gland. One of the most common causes is a failure of the thyroid gland to develop properly during fetal growth, a condition known as thyroid dysgenesis. This can result from genetic mutations or other unknown factors.

In rare cases, congenital hypothyroidism can be due to a problem in the hypothalamus or pituitary gland, which affects the release of thyroid-stimulating hormone (TSH), the hormone that prompts the thyroid to produce T4 and T3. This is referred to as central or secondary hypothyroidism.

Moreover, maternal factors such as iodine deficiency during pregnancy can also play a role, as iodine is essential for the production of thyroid hormones. 

As you can see, congenital hypothyroidism can arise from several issues in the body which is why early detection and treatment are vital.

Congenital Hypothyroidism Diagnosis


Early diagnosis is the cornerstone of managing congenital hypothyroidism effectively, and one of the most significant advancements in this regard has been the implementation of newborn screening programs.

Newborns are routinely screened for congenital hypothyroidism shortly after birth, typically within the first few days of life. The reason for the newborn screen is that the disease may not be picked up until there are developmental delays manifest which is too late. 

It’s the most common yet preventable cause of intellectual disability, and thus every newborn should be evaluated for it. This screening involves a simple blood test that either evaluates the TSH (thyroid-stimulating hormone) or thyroxine (T4) levels. TSH levels are elevated in infants with congenital hypothyroidism because their bodies are trying to compensate for the lack of thyroid hormones.

The newborn screen results come back in a few days and are often followed up by confirmatory lab work. If the screening test reveals elevated TSH levels, further confirmatory blood tests, such as measuring the levels of T4 (thyroxine) are conducted to confirm the diagnosis.

How do you treat it?

newborn screening

CH is treated with hormone replacement with levothyroxine. The medication that is prescribed is given in tablet form. Parents are instructed to crush the tablet prior to administering it.

The dose is adjusted based on blood work. In the first six months, every 4-8 weeks the doctor will order TSH (thyroid stimulating hormone) and free thyroxine (ft4) or total thyroxine (tt4). Based on these lab results, the medication will be adjusted to normalize these values. 

The TSH value will inform the provider if the dose of levothyroxine is appropriate. If the TSH value is elevated, then the infant is not receiving an adequate amount of hormone replacement. When the TSH is elevated this is referred to as hypothyroidism. If the TSH value is suppressed, then the infant is getting too much medication. This is referred to as hyperthyroidism.

There is no evidence to reveal how quickly the medication should be initiated in mild cases. That being said, most specialists initiate medication by 1 month of age or sooner to prevent neurocognitive delays. However, the more severe the levels are, the more promptly treatment is initiated.

How long will my child need treatment? 

Every child is different, so in some cases, the child may not need lifelong medication. The response to treatment and the amount of thyroid hormone replacement required may reveal how long the child needs treatment.

However, once an infant is started on medication, it is typically continued until 3 years of age. If your child has not required much of a dose increase during the course of treatment, then they may have transient hypothyroidism and may be able to come off the medication. It's always better to be safe than sorry when it comes to your child's health treatment. Thyroid hormone replacement is very safe when it is managed properly and the benefits of treating outweigh the risk of possible intellectual disability.

Ensure Your Child Gets the Right Treatment

Dr. McIver is a pediatric endocrinologist who specializes in treating all forms of hypothyroidism in children. You can learn more about these conditions by reading our blogs.

To discuss any concerns you may have, book a free consultation today!