In this article:
- Learning the causes of congenital hypothyroidism
- Symptoms you can expect with congenital hypothyroidism
- Treatment of congenital hypothyroidism in babies
- What to expect longterm
The thyroid is the small, butterfly-shaped gland at the base of your neck that produces hormones that regulate your body's energy use. When your thyroid hormone production drops (hypothyroidism), your body processes slow down and change, affecting many different systems in your body.
Congenital hypothyroidism is a condition that affects newborn babies. Between 1 in 2,000 to 1 in 4,000 babies are born with congenital hypothyroidism. However, this condition is rare in developed nations, including the United States.
One of the primary reasons congenital hypothyroidism is rare in developed nations is because iodine is widely available in most diets. Yet, problems with a baby's thyroid can still lead to congenital hypothyroidism, along with insufficient iodine from the mother's body.
If a baby does not have sufficient thyroid hormone while the mother is still pregnant or following birth, it can lead to severe complications, including intellectual disability.
Learning the causes of congenital hypothyroidism
Previously referred to as cretinism, congenital hypothyroidism is most frequently caused by the baby not getting enough iodine while in the womb. Iodine is an essential mineral in the production of thyroid hormone. Thyroid cells combine iodine and tyrosine, an amino acid, to make the thyroid hormones triiodothyronine (T3) and thyroxine (T4). The body then distributes T3 and T4 throughout the body to help control your metabolism.
Diets low In iodine
Our bodies are unable to make iodine, so it must come from our diet. However, it does not occur naturally in specific foods like other minerals (calcium and iron, for example). Thus, before the advent of iodized salt, conditions like congenital hypothyroidism were more prevalent in the United States.
Certain regions of the world do not have access to iodized salt. Some areas, including the land around the Himalayas, Alps, and Andes mountains, have iodine-poor soil. There are also many river valleys prone to flooding that also have soil with low iodine content. Thus, produce grown in these areas often lacks iodine, making babies more susceptible to having congenital hypothyroidism at birth.
Medications and genetic disorders
Besides iodine deficiency, another cause of congenital hypothyroidism is damage to the thyroid gland or malformation. These complications can arise in the following scenarios:
- The thyroid does not develop properly, or even at all, during development.
- There is a genetic defect that affects thyroid hormone production in the baby.
- The mother takes antithyroid drugs, sulfonamides, or lithium during pregnancy, all of which can compromise thyroid hormone production.
- The mother is treated with radioactive iodine or given antithyroid treatment during pregnancy to treat thyroid cancer.
Symptoms you can expect with congenital hypothyroidism
Babies with congenital hypothyroidism often do not have any telltale signs right after birth. Of course, if the mother underwent some form of treatment that could increase her baby's risk for congenital hypothyroidism, doctors would already anticipate this complication.
There often is a delay before symptoms present because the mother's thyroid hormone is still circulating in the baby's system right after birth.
The following symptoms may occur in a baby with congenital hypothyroidism:
- Poor weight gain and feeding
- Fatigue and lethargy despite excessive sleeping
- Stunted growth
- Abnormal bone growth
- Thickened facial features, including a thickened tongue
- Developmental delays
- Little crying
- Pale, cool, dry skin
- Myxedema (swelling of the skin)
- Poor muscle tone
- Hoarse cry
Treatment of congenital hypothyroidism in babies
Because the symptoms are so severe and can lead to devastating effects, newborn babies get routine thyroid screening.
A routine practice is to take small blood samples from the baby's heel (often referred to as a heel stick) and send them to the laboratory for evaluation. These tests measure thyroid-stimulating hormone (TSH) and thyroxine (T4). Generally, states require these screening tests for each newborn.
Doctors usually treat congenital hypothyroidism with thyroid hormone replacement medication. Treatment must start immediately, as developmental delays may become permanent within the first month following birth. Your doctor will determine the appropriate dose for your baby.
Your doctor will prescribe thyroid hormone replacement in the form of a pill, which will need to be crushed into a powder and added to breast milk or formula. Pediatric endocrinologists often recommend parents use a dropper to give the milk/medication mix to their baby to ensure they get all of the medication.
Some formulas can interfere with thyroid medication absorption, including soy-based formulas and those with extra iron and calcium. If you use these formulas, you will want to mix the medication with a little water instead.
What to expect longterm
Most babies born with congenital hypothyroidism do not grow up with severe developmental and growth delays if:
- They are started on treatment right away, and
- They receive regular follow-up care with their doctors.
As you can see, early action is critical in preventing longer-term disabilities.
Children born with congenital hypothyroidism are cared for by their general pediatrician and a pediatric endocrinologist. They must be seen regularly by both of their doctors.
Regarding medication, most children born with congenital hypothyroidism will be on lifelong thyroid medication. However, in some cases, a pediatric endocrinologist may trial a young patient off of the drug to see if the thyroid can start to produce hormones on its own.
The medication dose will increase as the child grows. Regular blood work will also be necessary, especially when the dose changes.
Although congenital hypothyroidism is rare in developed nations, it can still happen. With proper medical care and regular follow-up, both mothers and their babies can overcome the challenges presented by this condition.
A note from Paloma Health
Paloma Health thyroid doctors do not test for or treat congenital hypothyroidism. Biomarker ranges are different for those under the age of 18, and we don't currently have pediatric testing capability. We recommend anyone under 18 see a pediatric endocrinologist.