Risk Factors for Thyroid Function Test Abnormalities During Pregnancy: A Systematic Review of the Literature to Validate Current Risk Factors and Identify Novel Ones

Background: International guidelines recommend that the indication to perform thyroid function testing during pregnancy is based on the presence of risk factors for thyroid function test abnormalities. However, the discriminative ability of currently recommended risk factors is questionable. To inform on an update of the American Thyroid Association Guidelines for the Diagnosis and Management of Thyroid Disease in Preconception, Pregnancy, and the Postpartum, we aimed to systematically review the literature to evaluate evidence for current risk factors and potential novel ones for thyroid function test abnormalities in pregnancy.