Preexisting Thyroid Disease in Pregnancy: A Brief Overview

Maternal thyroid disease, with both an excess or deficiency of thyroid hormone, raises the risk profile of affected pregnancies with regards to preeclampsia, preterm birth, placental problems, thyroid derangement of the fetus and neonate, and neurodevelopment of exposed fetuses later in life. Fortunately, close and tight management of thyroid disease within the fluctuating physiologic milieu of pregnancy offers opportunities to significantly improve perinatal outcomes. However, despite guidelines offered by American College of Obstetrics and Gynecology (ACOG) and American Thyroid Association (ATA), controversy persists regarding interpretation of thyroid labs, screening for disease, surveillance, fetal and placental thyroid physiology, and optimal medication and management strategies. This is a brief overview of what is known and unknown regarding thyroid disease and its impact on maternal, fetal, and pregnancy health.