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Screening for thyroid disease in pregnancy


  • Normal TSH values in pregnancy: 2.5-4.0 mIU/L
  • Normal fT4 values in pregnancy: 0.7-1.8 ng/dL
  • Definition of subclinical hypothyroidism: serum TSH 2.5 mIU/L to 10mIU/L, fT4 concentration 0.7 ng/dL to 1.8 ng/dL, and absence of symptoms


  • Overt maternal hypothyroidism hinders childhood neurodevelopment
  • Maternal subclinical hypothyroidism or hypothyroxinemia may be associated with diminished IQ in offspring
  • Overt hyperthyroidism complicating pregnancy is associated with increased risk of spontaneous pregnancy loss, congestive heart failure, thyroid storm, preterm birth, preeclampsia, and fetal growth restriction.


  • Routine thyroid screening in pregnancy is not recommended
  • Thyroid testing in pregnancy should be conducted for women “at risk,” including known thyroid disease,
  • symptoms of overt thyroid disease, suspected goiter, autoimmune medical disorders such as Type 1 diabetes mellitus
  • Routine treatment of subclinical hypothyroidism is not recommended
  • Routine thyroid testing of women with hyperemesis gravidarum is not recommended

Last Reaffirmed: Aug 1, 2014