Thyroid function test are performed in the well baby nursery to newborn infants of mothers with hypothyroidism, or as part of neonatal jaundice investigation. As thyroid function test are also part of the national screening test program, the investigators raised the option that the above management is unnecessary, and managed a study to investigate it.

Thyroid function test are performed in the well baby nursery to newborn infants of mothers with hypothyroidism, or as part of neonatal jaundice investigation. As thyroid function test are also part of the national screening test program, the investigators raised the option that the above management is unnecessary, and managed a study to investigate it.

The study is retrospective. About 4000 infants are born in the center every year. The investigators wish to examine data for 10 years, i.e. about 40000 files.

The investigators will collect all the national screening test program results and compare them to the thyroid function test performed in that center.

Inclusion Criteria:

• Infants born in our medical center
• Term infants
• Admitted to well baby nursery and stayed there until discharge

Exclusion Criteria:

• Preterm infants
• Transferred to neonatal intensive care unit for any reason

All infants born in our medical center

Individual participant data will be erased.