Maternal Iodine Requirements in Pregnancy and Lactation: Critical roles and monitoring strategies

Iodine plays a vital role in fetal neurodevelopment and is closely linked to thyroid function in both mothers and infants. Iodine deficiency during pregnancy is associated with adverse obstetric outcomes, impaired fetal growth, and in severe cases, can result in neonatal cretinism. An adequate iodine status in pregnancy is defined by a median urinary iodine concentration of 150–249 µg/L. Several methods are available to assess iodine sufficiency in pregnant and lactating women, each with its own strengths and limitations. These include urinary iodine concentration, serum iodine levels, serum thyroglobulin, breastmilk iodine concentration, neonatal thyroid-stimulating hormone levels, and thyroid volume assessment. While iodine supplementation is crucial in deficiency states, excessive iodine intake can also disrupt thyroid function, potentially leading to either hyperthyroidism or hypothyroidism. Therefore, monitoring and maintaining appropriate iodine levels during pregnancy and lactation is essential for maternal and neonatal health.