Euthyroid Hashimoto thyroiditis in pregnancy

Hashimoto thyroiditis is diagnosed in people with positive thyroid autoantibodies, usually thyroid peroxidase antibodies. Hashimoto thyroiditis commonly exists without clinically significant hypothyroidism (euthyroid Hashimoto thyroiditis), so treatment is often not required. However, these people are at increased risk of developing subclinical or overt hypothyroidism, most notably during pregnancy when the thyroid is unable to meet the increased requirement for thyroid hormone. Pregnant women with Hashimoto thyroiditis are also at increased risk of spontaneous miscarriage and preterm delivery.

If a woman with euthyroid Hashimoto thyroiditis becomes pregnant, monitor her thyroid function to determine whether she has progressed to hypothyroidism; see New-onset or previously untreated hypothyroidism in pregnancy.

Women with Hashimoto thyroiditis are also at increased risk of postpartum thyroiditis (see Postpartum thyroid dysfunction). Counsel women about the symptoms of postpartum thyroiditis and advise them to seek medical advice if symptoms occur.