Research progress on hypothyroidism during pregnancy

Because of an increase in thyroxine-binding globulin,human chorionic gonadotropin and increased maternal renal clearance of iodide during pregnancy,the production,circulation,metabolism and regulation of thyroid hormones change with gestational age.These lead to the difficulty in the diagnosis and management of thyroid disorders during pregnancy.It is important to establish pregnancy specific reference intervals for thyrotropin and thyroid hormones,which will reduce the rate of misdiagnosis and missed diagnosis of thyroid disorders during pregnancy.Thyroid insufficiency during pregnancy including overt hypothyroidism,subclinical hypothyroidism and hypothyroxinemia will damage fetal brain development.Pregnant women with hypothyroidism should accept levothyroxine therapy.The aim of levothyroxine treatment is to keep the serum thyrotropin Ievels of pregnant women under control 0.3 to 2.5 mIU/L for the first trimester,0.3 to 3.0 mIU/L or trimester-specific reference intervals for the second and the third trimester. Key words: Pregnancy; Hypothyroidism