Pre-pregnancy screening for people at high risk of hypothyroidism can lead to some under-diagnosis, so universal screening is carried out in areas where it is possible to do so with the patient’s knowledge. High-risk groups include: 1) individuals with a personal and family history of thyroid disease; 2) goiter; 3) surgical removal of the thyroid gland; 4) after 131I treatment; 5) individuals with a personal and family history of autoimmune disease; 6) previous TSH elevation; and 7) previous thyroid autoantibody positivity.