Hypothyroidism is a condition that results from an under-active thyroid that does not produce enough thyroid hormone. ‘Congenital’ means that this condition is present at birth.
Very early in an unborn baby's development the thyroid gland moves from the back of the tongue to its normal position in the neck. In some babies this doesn’t happen and the gland does not develop at all. In others, the thyroid gland is higher in the neck than normal and does not work as well. These are the most common types of congenital hypothyroidism. Normally the risk of having another child with this type of congenital hypothyroidism is very low.
Less often the thyroid gland appears normal and is in the right place but does not produce sufficient thyroxine. This type of thyroid disorder can be inherited. If this is suspected you may be referred to a genetic counsellor who will be able to advise about risks in future pregnancies.
How common is congenital hypothyroidism?
Although hypothyroidism is a common disorder in adults, it is less common in children. One child in every 3,500 is born with hypothyroidism in the UK. It is more common in girls.