Hypothyroidism is a clinical disorder commonly encountered by the primary care physician.
Untreated hypothyroidism can contribute to hypertension, dyslipidaemia, infertility, cognitive
impairment, and neuromuscular dysfunction. Data derived from the National Health and
Nutrition Examination Survey suggest that about one in 300 persons in the United States
has hypothyroidism. The prevalence increases with age, and is higher in females than in
males. Hypothyroidism may occur as a result of primary gland failure or insufficient thyroid …

It is the purpose of this article to briefly review the initial development and subsequent
evolution of newborn screening programs to detect infants with congenital hypothyroidism
(CH) and then to provide an update of the advantages and disadvantages of the main test
strategies. Pilot programs began screening newborn populations in North America in the
mid‐1970s using either primary thyroxine (T4)‐follow‐up thyroid stimulating hormone (TSH)
or primary TSH testing. Many programs in the United States and around the world continue …