Maternal iodine excess: an uncommon cause of acquired neonatal hypothyroidism.

Background Excessive iodine exposure is an often overlooked cause of neonatal hypothyroidism. Case presentation We present an infant with iodine-induced hypothyroidism, which was detected at age 15 days by newborn screening. The infant's iodine excess resulted from maternal intake of seaweed soup both during and after pregnancy. Treatment included discontinuation of seaweed soup, temporary interruption of breastfeeding and short-term levothyroxine therapy. By age 4 months, the infant's hypothyroidism had resolved, and her growth and development were normal. Conclusions This case illustrates the importance of considering excess dietary iodine as a possible cause of hypothyroidism in infants.