A common, self-limiting thyroid disorder seen in preterm infants that is characterized by abnormally low serum levels of thyroxine and free thyroxine with normal serum levels of thyroid stimulating hormone. The disease is MONDO_0015792 (transient congenital hypothyroidism). Also known as: THOP, hypothyroxinemia of prematurity, transient hypothyroxinemia of prematurity.