ABSTRACT
BACKGROUND: Resistance to thyroid hormone manifests as high serum levels of free thyroxine and free triiodothyronine, with nonsuppressed thyroid stimulating hormone (TSH) levels. We report a case series of three patients with this condition, the changes in thyroid function tests during their pregnancies, and their obstetric outcome. CASES: Three pregnant women with asymptomatic resistance to thyroid hormone developed goiter, and the levels of TSH in one case suppressed progressively, necessitating treatment. The neonates born to all these reported cases were healthy, with normal growth scans and normal thyroid function tests at 1 week. CONCLUSION: The prenatal diagnosis of resistance to thyroid hormone is important for adequate management of both mother and fetus in pregnancy and avoiding unnecessary intervention. The only clinical manifestation of resistance to thyroid hormone may be the presence of a goiter, and treatment in asymptomatic patients solely to normalize thyroid hormone levels is not required during pregnancy. Careful evaluation of the neonate is indicated after delivery.
