Subclinical Hypothyroidism and Thyroid Autoimmunity in Pregnancy: To Treat or Not to Treat.

Subclinical hypothyroidism and thyroid autoimmunity in pregnancy are common conditions. They are both associated with adverse maternal and offspring outcomes. Women with thyroid autoimmunity should be monitored with regular thyroid function tests preconception and during gestation to identify women who develop hypothyroidism. The effectiveness of thyroid hormone treatment in reducing adverse outcomes in pregnancy has been studied in a number of randomized controlled trials. Current evidence shows obstetrical benefits of levothyroxine treatment in pregnant women with a thyroid-stimulating hormone level greater than 4 mU/L.