ABSTRACT
Pregnancy has a profound effect on the thyroid gland function. Numerous physiological changes occur during pregnancy including hormonal alterations and increased metabolic demands. Thyroid disorders may affect the progression of pregnancy, the pregnant woman, and the developing fetus. Iodine requirements are higher in pregnancy due to enhanced T4 production, increased renal iodine clearance, and fetal iodine demands. Women with limited thyroid reserve or iodine deficiency can develop hypothyroidism due to the increased metabolic demands during pregnancy. Hypothyroidism during pregnancy may adversely affect maternal and fetal outcomes. It has been associated with an increased risk of spontaneous abortion. In continuing pregnancies, hypothyroidism has been associated with increased risk of several complications such as preterm delivery, gestational hypertension, placental abruption, low birth weight, cesarean section, and postpartum hemorrhage. Universal screening for hypothyroidism in asymptomatic women who are pregnant or are planning pregnancy is controversial due to insufficient evidence that it is beneficial.
