A Case of Hypothyroidism in Remission during Pregnancy

Hypothyroidism should be treated in pregnancy, because it has been associated with an increased risk of adverse pregnancy complications, as well as detrimental effects upon fetal neurocognitive development. The goal of L-thyroxine (LT4) treatment is to normalize maternal serum TSH values within the trimester-specific pregnancy reference range. 50% to 85% of hypothyroid women being treated with exogenous LT4 need to increase the dose during pregnancy. In this study, we report a case of a 29-year-old woman with hypothyroidism who had been in remission and discontinued LT4 treatment during her pregnancy. Three months after delivery she had a relapse of hypothyroidism and was retreated with LT4. Many factors can influence the gestational requirement for LT4, therefore maternal serum TSH should be monitored and the LT4 dose should be adjusted in pregnant patients with treated hypothyroidism.