What is Congenital Hypothyroidism?

Congenital hypothyroidism is a low level of thyroid hormone present from birth and caused either by a genetic condition or by abnormalities in fetal development, often the result of exposure to environmental hazards, although not always. This condition is not curable, but it is treatable, and when it is caught early, the patient may experience no ill effects from the congenital hypothyroidism. Many medical facilities routinely screen for this condition at birth, so that it can be identified and addressed if it is present.

In some babies, the thyroid is underdeveloped, in the wrong place, or not present at all. Other cases involve malfunctions of the thyroid that cause it to underproduce hormones. All of these situations result in abnormally low levels of thyroid hormone, causing health problems because of the interconnected nature of the endocrine system and the rest of the body. In rare cases, babies have low thyroid hormone levels temporarily because of hormones in breast milk. In these instances, once the baby begins producing thyroid hormone independently, levels will rise and this will show on a blood test to follow up on the low levels observed at birth.

Around one in every 3,000-4,000 babies has congenital hypothyroidism, with girls being twice as likely to get it. At birth, the baby usually looks and behaves as one would expect from a healthy baby. Over time, the baby will become sluggish and fussy. Puffy face, jaundice, poor feeding, and constipation can develop. If the low levels of thyroid hormone are not addressed, the developing child will experience growth delays, in addition to developmental delays.

Historically, congenital hypothyroidism was not treated, and people developed physical and intellectual disabilities as a result. The term “cretin” was used to refer to people who experienced disabilities caused by low levels of thyroid hormone. Today, screening is performed within 72 hours of birth for most infants. If the screening reveals low levels of thyroid hormone, the baby is given supplemental thyroid hormone by mouth. Permanent disability caused by congenital hypothyroidism is very easy to prevent.

Treating congenital hypothyroidism with hormones requires periodic tests to confirm that the developing baby is getting enough hormones. As the child grows up, the dosage will need to be increased. People continue hormone supplementation for life, ensuring that their bodies get enough of the hormone to function. Consistent doses of thyroid hormone eliminate the developmental delays that would otherwise occur with congenital hypothyroidism.