What is the primary cause of hyperthyroidism in newborns?

The primary cause of hyperthyroidism in newborns is indeed Graves disease in the mother. Graves disease is an autoimmune disorder characterized by the overproduction of thyroid hormones, which can affect the fetus during pregnancy. Maternal antibodies can cross the placenta and stimulate the fetal thyroid gland, leading to hyperthyroidism in the newborn.

In cases where a mother has Graves disease, the newborn may experience symptoms related to excess thyroid hormone, including irritability, feeding difficulties, and potentially an enlarged thyroid gland (goiter). This association highlights the importance of maternal health and the impact autoimmune conditions can have on the developing fetus.

While an overdose of thyroid medication, genetic mutations, and dietary deficiencies can contribute to various thyroid issues, they are not the primary causes of hyperthyroidism in newborns. An overdose of medication might lead to hyperthyroidism, but that scenario is less common compared to the impact of maternal Graves disease. Genetic mutations are typically related to congenital conditions and not specifically to hyperthyroidism. Dietary deficiencies would more likely result in hypothyroidism rather than hyperthyroidism.