The primary cause of congenital Hypothyroidism is a developmental defect of the thyroid gland, resulting in an absent, underdeveloped or abnormal positioned gland. In other instances, a normally developed thyroid gland may be unable to produce enough thyroxine due to enzymes deficiencies. These scenarios may either be attributed to genetic factors or remain unexplained.

Most infants with Congenital Hypothyroidism are identified through compulsory newborn screening before they develop symptoms. If diagnosis is delayed, symptoms may include constipation, excessive sleepiness, poor feeding and prolonged jaundice. If identified later in childhood, it can result in short stature, overweight and intellectual impairment.

In Singapore, all newborns undergo screening for Congenital Hypothyroidism using their umbilical cord blood Thyroid-Stimulating Hormone (TSH) level. Elevated cord blood TSH levels require a confirmatory blood test measuring TSH and thyroid hormone levels. A diagnosis is confirmed if the blood test indicates high TSH levels, followed by special investigations, including a scintigraphy scan, to identify the cause.

Treatment involves daily oral administration of thyroxine tablets. The dosage is adjusted as the child grows, based on regular blood test results. Parents should consult a paediatric endocrinologist for ongoing management and follow-up.

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• Joseph R, Lee YS, Ng SCY, Loke KY (2003). Detection through screening of maternal thyrotoxicosis induced central hypothyroidism in newborns. The Southeast Asian Journal of Tropical Medicine and Public Health, 34 Suppl 3:150-1.
• Lee YS, Loke KY, Ng SCY, Joseph R (2002). Maternal thyrotoxicosis causing central hypothyroidism in infants. Journal of Paediatrics and Child Health, 38(2):206-8.