Overview of thyroid disorders in pregnancy

Thyroid disorders rank as the second most common endocrine abnormalities during pregnancy, posing significant challenges for clinical diagnosis due to overlapping symptoms with normal pregnancy. Thyroid hormones play a critical role in fetal growth and neurocognitive development, necessitating precise interpretation of maternal thyroid function tests, which differ from non-pregnant states. Proper management of thyroid dysfunction can significantly reduce morbidity in both mothers and their fetuses.This review explores the physiological changes in thyroid function during pregnancy, the epidemiology of thyroid disorders, and current guidelines for diagnosis and management. Pregnancy induces anatomical and physiological changes in the thyroid gland, including an increase in gland size and alterations in hormone levels influenced by factors such as hCG and estrogen. These changes necessitate trimester-specific reference ranges for thyroid function tests, as the American Thyroid Association and the American College of Obstetricians and Gynecologists recommended. Hyperthyroidism, primarily caused by Graves' disease and gestational transient thyrotoxicosis, can lead to complications like preeclampsia, preterm birth, and fetal hyperthyroidism. Management includes antithyroid drugs, with careful monitoring to balance maternal and fetal risks. Hypothyroidism, including subclinical and overt forms, is predominantly due to autoimmune thyroiditis and poses risks such as spontaneous abortion, preterm delivery, and impaired neurodevelopment in offspring. The review discusses the debated benefits of levothyroxine treatment for subclinical hypothyroidism, highlighting the need for further research to establish clear guidelines.Given the complex interplay between thyroid function and pregnancy outcomes, this comprehensive review underscores the importance of tailored, evidence-based approaches to managing thyroid disorders in pregnant women.