Thyroid related
Screening pregnancy related thyroid disorders

Topic Completed: 1 March 2011

Revised: 31 December 2018, last major update March 2011

Copyright: (c) 2002-2016,, Inc.

PubMed Search: Screening [title] pregnancy thyroid disorders

Nat Pernick, M.D.
Page views in 2018: 19
Page views in 2019 to date: 18
Cite this page: Pernick N. Screening-pregnancy related thyroid disorders. website. Accessed December 14th, 2019.
Definition / general
  • Overt thyroid disease is present in 1% of pregnant women, 2 - 3% have subclinical hypothyroidism, 10 - 15% have positive anti-thyroid antibodies
  • All pregnant and lactating women require additional iodine intake
    • Monitor with urinary iodine concentration
  • Hypothyroidism should be corrected before initiation of pregnancy and euthyroidism maintained throughout (Ther Drug Monit 2006;28:431)
  • However, low T4 with normal TSH may not affect perinatal outcome (Obstet Gynecol 2007;109:1129)
  • Therapy also recommended for subclinical maternal hypothyroidism, although risk to fetus is unknown
  • Maternal hyperthyroidism (Graves disease, Nat Clin Pract Endocrinol Metab 2007;3:470) can cause fetal hyperthyroidism (due to transplacental TSH-receptor antibodies)
    • Also associated with maternal hypothyroidism due to anti-thyroid drugs
  • Maternal autoimmune thyroid disease is associated with increased risk of miscarriage (J Coll Physicians Surg Pak 2006;16:468)
    • These women should have TSH monitored for increased levels
  • Postpartum thyroiditis occurs in 2 - 5% (Obstet Gynecol 2006;108:1283)
  • Thyroid function screening recommended for women with history of thyroid disease (Gynecol Endocrinol 2007;23:138), family history, goiter, thyroid antibodies or autoimmune disorders, signs / symptoms suggestive of thyroid disease, type I diabetes, prior head and neck radiation, history of miscarriage or preterm delivery (J Clin Pathol 2005;58:449)
  • However, up to 1/3 of women with hypothyroidism would be missed by targeted screening (J Clin Endocrinol Metab 2007;92:203)
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