Monitoring and effects of iodine deficiency in pregnancy: still an unsolved problem?

Iodine is required for the production of thyroid hormone. Thyroid hormone affects many metabolic processes in the body, including maturation of the central nervous system. In early pregnancy, the fetus is dependent on maternal thyroid hormone for normal brain development. If iodine deficiency leads to inadequate production of thyroid hormone during pregnancy, irreversible brain damage can result in the fetus. Therefore, achieving adequate iodine nutrition during pregnancy is an important public health objective. Although there have been tremendous gains over the last several decades in our understanding of the effects of iodine deficiency in pregnancy and how to combat them, a number of questions remain about how best to monitor the iodine status of pregnant populations, the effects of mild to moderate iodine deficiency on maternal and child outcomes, the safe upper limit of daily iodine intake in pregnant women and the risks and benefits of iodine supplementation for mildly iodine-deficient pregnant women.