Congenital hypothyroidism (CHT) is a condition resulting from an absent or under-developed thyroid gland (dysgenesis), or one that has developed but cannot make thyroid hormone because of a problem with the ‘production line’ (dyshormonogenesis). Babies with CHT cannot produce enough thyroid hormone (thyroxine) for the body’s needs. Without adequate thyroxine, babies do not grow properly and can develop permanent, serious physical problems and learning disabilities. Babies with CHT are treated lifelong with levothyroxine to replace what their body is unable to make. This treatment allows them to develop normally. 

If your baby’s Thyroid Stimulating Hormone (TSH) is high on the newborn bloodspot (heel prick) test, they will screen positive for a ‘suspected condition’. Your baby will require a small blood sample taken from a vein to confirm whether their thyroid hormone is low and confirm their CHT diagnosis.

Usually, the local hospital’s paediatrician will phone you to arrange a testing appointment, generally on the same day. After your testing appointment, your health visitor will give you the screening result letter, along with information about CHT. This will be done in a face-to-face appointment to ensure you can ask any questions you have and be supported during your discussion with them.

Your baby will then be treated with levothyroxine (taken orally) each day to replace what the body cannot make properly. This treatment should start as soon as possible and the dose will be carefully calculated according to factors, such as their weight. This dose will be adjusted regularly as your child grows.

Your baby’s care will be under a paediatric endocrinologist, or a paediatrician with a special interest in endocrinology. Babies and children with CHT are closely monitored with regular hospital appointments. Typically, your baby’s thyroid function will be checked every few weeks during the first few months of life. During infancy and childhood, these will be checked every two to six months. Your baby’s care will be supported by the specialist nurses attached to the CHT team. Your health visitor will also be able to seek support from the specialist nurse to help ensure consistent care.

See our guide to congenital hypothyroidism 

Find information and support for children with thyroid conditions