Thyroid hormone deficiency present at birth
Congenital hypothyroidism (CH) is a condition where there is a lack of thyroid hormones in a baby from the moment of birth (1).
Thyroid hormones are essential for normal human growth and development, especially during the first few years of life. A universal newborn screening was developed four decades ago to help prevent the many consequences of CH.
Types of congenital hypothyroidism
CH affects 1 in 2,000 newborns. There are several variations of the conditions (2–7).
Based on the severity (4):
- Severe congenital hypothyroidism — needs to be treated immediately
- Mild congenital hypothyroidism
Based on the cause (4, 6, 7, 8–12):
Primary congenital hypothyroidism
- 90% of cases
- Caused by problems in thyroid development or an inability of the thyroid to produce enough hormones
Central congenital hypothyroidism
- 10% of cases
- Caused by pituitary gland dysfunction and low levels of TSH
Based on the duration (13,14):
- Permanent – a lack of thyroid hormones that requires lifelong treatment
A temporary deficiency of thyroid hormones at birth, recovering to normal thyroid hormone levels within a few weeks to a few months. Most commonly it affects infants in the areas of iodine deficiency, exposure to thyroid blocking drugs before birth, high iodine, certain genetic mutations and liver dysfunction. It is very frequent, with 2 in 5 newborns having it.
How is CH diagnosed? (15, 16)
TSH levels between 6 and 15 mIU/L and decreased T4
- Severe: when FT4 is <5 pmol/l
- Moderate: when FT4 is 5 to 10 pmol/l
- Light: when FT4 is 10 to 15 pmol/l
Signs and symptoms of congenital hypothyroidism
Most symptoms of CH are not typical to having an underactive thyroid, because while in utereo there are still some hormones coming from the mother’s placenta. These symptoms persist after birth (1, 17–19):
- High birth weight
- Umbilical hernia
- Excessive sleeping
- Unusually large tongue (macroglossia)
- Cold or patchy and irregularly coloured skin (mottled skin)
- Persistent jaundice (yellow skin or eyes)
- Puffy face
- Palpable goiter
Congenital hypothyroidism treatment
Levothyroxine is the first line treatment for CH. The recommended dose starts at 10 to 15 mcg per day. This is typically further adjusted individually.
Serum TSH and free T4 should be measured every 1–2 months in the first six months of a baby’s life, and every 3–4 months thereafter.
Treatment usually continues until three years of age, when doctors then assess how to continue (20, 21). Monitoring of child should continue in order to avoid overtreatment with T4 (22, 23).
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Disclaimer: This information is not intended to mitigate, prevent, treat, cure or diagnose any disease or condition. If you want to change your treatment, lifestyle, your diet, include supplements in your diet or have concerns about your health, please consult your doctor before trying new approaches.
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- Lim G, et al. Early discontinuation of thyroxine therapy is possible in most very low-birthweight infants with hypothyroidism detected by screening, 2014
- Park ES, et al. Factors associated with permanent hypothyroidism in infants with congenital hypothyroidism, 2019
- Bongers-Schokking JJ, et al. Cognitive development in congenital hypothyroidism: is overtreatment a greater threat than undertreatment, 2013
- Alvarez M, et al. Episodes of overtreatment during the first six months in children with congenital hypothyroidism and their relationships with sustained attention and inhibitory control at school age, 2010
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