Interpretation of thyroid function tests during pregnancy

• Published in: Baillière's best practice & research. Clinical endocrinology & metabolism Vol. 34; no. 4; p. 101431
• Main Authors: Visser, W. Edward, Peeters, Robin P.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01.07.2020
• Subjects: Adult; Data Interpretation, Statistical; Female; FT4; Humans; Pregnancy; Pregnancy Complications - blood; Pregnancy Complications - diagnosis; Prenatal Diagnosis - methods; Prenatal Diagnosis - standards; Reference Values; Thyroid Diseases - blood; Thyroid Diseases - diagnosis; thyroid function tests; Thyroid Function Tests - methods; Thyroid Function Tests - standards; thyroid hormone; Thyroid Hormones - analysis; Thyroid Hormones - blood; Thyrotropin - analysis; Thyrotropin - blood; Thyroxine - analysis; Thyroxine - blood; TPO-antibodies; Triiodothyronine - analysis; Triiodothyronine - blood; TSH; TSH; TPO-antibodies; thyroid hormone; pregnancy; thyroid function tests; FT4
• ISSN: 1521-690X; 1878-1594
• DOI: 10.1016/j.beem.2020.101431

Thyroid hormones are crucial for normal pregnancy and fetal development. Large physiological changes occur during pregnancy, posing challenges for the correct interpretation of thyroid function tests. TSH concentrations are the principal first test to rule out thyroid disease taking into account trimester-specific reference ranges. Free T4 (FT4) measurements by immuno-assays may be subject to interference by endogenous and exogenous factors. The relevance of measuring free T3 (FT3) during pregnancy is unclear. Thyroid autoimmunity is well-reflected by the presence of antibodies against TPO. TPO-antibody positivity is associated with an increased risk of adverse pregnancy outcomes.