Iodine supplementation during pregnancy and lactation.

DIETARY IODINE INTAKE IS OBLIGATORY FOR THE PROduction of thyroid hormones. Despite substantial public health advances over the past 3 decades, iodine deficiency currently affects 1.92 billion people globally. Dietary iodine requirements are increased during pregnancy due to increased thyroid hormone production, increased renal iodine losses, and fetal iodine requirements. Dietary requirements remain increased in lactation due to the concentration of iodine in breast milk. Adverse effects of iodine deficiency in pregnancy, when the deficiency leads to severe decreases in maternal thyroxine (T4), include maternal and fetal goiter, cretinism, intellectual impairments, neonatal hypothyroidism, and increased pregnancy loss and infant mortality. Decreases in maternal T4 associated with even mild iodine deficiency may have adverse effects on the cognitive function of offspring, and iodine deficiency remains the leading cause of preventable intellectual disability worldwide.