Congenital Hypothyroidism - Its impact on your newborn’s growth and development

Would you be able to detect if your newborn child's thyroid gland is producing less of the thyroid hormones, that play an important role in your child's growth and development?

You probably won't! That is because it is difficult to spot the signs and symptoms of an underactive thyroid gland (also called hypothyroidism) in the early stages.

Let us now understand what a thyroid gland is and what are its functions:

Thyroid gland and its function: The understanding

The thyroid gland is a butterfly-shaped tissue in the lower neck. It produces two iodine-containing hormones- Triiodothyronone (T3) and Thyroxine (T4) These hormones play a critical role in regulating growth, brain development, and metabolism.  

The thyroid gland is controlled by another gland called the pituitary gland, which is located at the base of the brain. (1)

Why is the thyroid hormone important?

Thyroid hormones has a key role to play. Some of the important functions of thyroid hormone are listed below: (1,2)

1. Regulate Body temperature

2. Maintain normal functioning of the digestive tract

3. Growth & Development

4. Maintains a normal heart rate

5. Normal development of brain and nervous system

6. Maintain adequate appetite

What is congenital hypothyroidism?

Congenital hypothyroidism is caused either by absence of thyroid gland or a partial or complete loss of function of the thyroid gland (hypothyroidism) that affects infants from birth or even within the womb (congenital), thereby affecting their overall growth and development. 

Children with congenital hypothyroidism have lower-than-normal levels of these important hormones.(3)

This occurs in about 1 in 1130 children and is most often permanent and treatment is lifelong.(4)

What are the causes of Congenital Hypothyroidism?

Hypothyroidism in the newborn may be caused by:(2,3)

• A missing, poorly formed, or abnormally small thyroid gland

• A genetic defect that affects thyroid hormone production

• Too little iodine in the mother’s diet during pregnancy

• Undiagnosed thyroid disorder during pregnancy

• Radioactive iodine or antithyroid treatment in mother during pregnancy

• Use of medicines that disrupt thyroid hormone production — such as antithyroid drugs, sulfonamides, or lithium — during pregnancy

Congenital hypothyroidism is usually not inherited from parents. This means if one child is affected, it is unlikely that other children you may have in the future will suffer from the same condition.

What are the common symptoms that your child will show if they are born with an underactive thyroid (congenital hypothyroidism)? 

Most of the affected infants have very few symptoms and this makes detection difficult. 

Some of the symptoms and signs that may be visible include(5)

• Poor feeding

• Constipation

• Dry, brittle hair

• Coarse cry (rough cry)

• Jaundice (skin and whites of the eyes look yellow)

• Lack of muscle tone (floppy infant)

• Umbilical hernia (Outward protrusion of the navel)

• Sleepiness

• Inactiveness

• Dull look

• Puffy face

• A thick tongue that sticks out

• Slow growth

• Very large soft spots on the skull (fontanelles)

• Widely separated skull bones

The symptoms of hypothyroidism are vague and therefore often parents miss these or confuse these with something else.(6) However, if you see any of these symptoms, take your child to your pediatrician or endocrinologist (superspecialist for hormone disorders) immediately and get them screened.

The only way to know for sure whether your child is born with hypothyroidism is to perform a blood test at birth –which is called newborn screening(6)

If my newborn is detected with hypothyroidism, is it possible to know exactly why he is suffering from this problem?

Yes. In addition to thyroid testing, your endocrinologist may also advise a Technetium 99 scan of your child to look for presence, absence or malposition of thyroid gland and also, sometimes an ultrasound of thyroid gland to further know the cause of hypothyroidism which will help in deciding the dose and duration of thyroid treatment.

Why is it important to detect hypothyroidism at an early age?

In newborns, hypothyroidism is serious and needs early diagnosis and treatment to prevent the onset of brain damage and for their growth and development. Congenital hypothyroidism is the most common preventable cause of mental retardation. Getting diagnosed early can lead to a better intellectual outcome. Newborns who are diagnosed and treated in the first month usually have normal intelligence and won't face long term problems. Early treatment helps to prevent the development of mental retardation, learning disabilities, and/or growth delays later in childhood. Untreated mild hypothyroidism can lead to severe intellectual disability and growth problems. The nervous system goes through important development during the first few months after birth. Therefore, it is very important to check your baby’s thyroid levels as soon as they are born.

Please check with your gynecologist or pediatrician proactively and make sure your baby is screened for hypothyroidism. (5,6)

Screening for Hypothyroidism in the newborn 

The best time to diagnose congenital hypothyroidism is when the child is born. All guidelines recommends screening in every newborn on day 3 – day 5 postnatally. Once hypothyroidism is detected and treatment with thyroxine is started, , blood tests are checked every 1 to 2 months up to 6 months of age and then every 2 to 3 months thereafter(1)

How long do I need to continue thyroxine treatment?

Usually lifelong. In very rare cases, treatment can be stopped after 3 years.But that can be decided only by your endocrinologist after  the child reaches 3 years of age –depending on the cause of hypothyroidism. But remember –once your infant has been diagnosed with congenital hypothyroidism and started on thyroxine –DO NOT –under any circumstances stop his/her thyroxine tablet till 3 years of age!

Hypothyroidism can be manageable without much hassle

• Your baby does not require any special diet and does not need to receive extra iodine. A healthy nutritious diet is important for growth, mental development, and good health.

• There are no restrictions on giving any other medications that are prescribed by a doctor. Make sure your child receives routine immunizations and regular checkups.(5,6)

It is important that all parents should get the baby's thyroid level check after the baby is born as per doctor's advice. Do not worry if your child is diagnosed with hypothyroidism. Work with your child's endocrinologist to manage your child's condition. With the right medication or intervention, your child will get better.