Management of pregnant women with or at risk for hypothyroidism
Refer to UpToDate content on screening for thyroid dysfunction during pregnancy for identification of pregnant women at risk for hypothyroidism.
TSH: thyroid-stimulating hormone; TPO: thyroid peroxidase antibodies; T4: thyroxine.
* 4 mU/L or population and trimester-specific upper limit of normal, if available.
¶ The presence of TPO antibodies guides management of pregnant women. It informs the extent of autoimmunity, the risk of pregnancy loss, and the risk of postpartum thyroid dysfunction.
Δ Free T4 should be interpreted using assay method and trimester-specific reference ranges.
◊ For women at high risk for developing hypothyroidism (eg, radioiodine treatment, hemithyroidectomy, exposure to high-dose irradiation of the head and neck), monitor TSH at least once more during the first trimester and again mid-pregnancy. Treat with levothyroxine if TSH rises above 4 mU/L.
§ Suggestion is based upon weak evidence. The approach to management varies. If a decision is made not to treat, measure TSH approximately every 4 weeks during the first trimester, then once in each of the second and third trimesters to monitor for the development of hypothyroidism. Treat with levothyroxine if TSH rises above 4 mU/L.
REF. UpToDate 2019.1.10
