The importance of transient hypothyroxinemia of prematurity and its controversial management

According to the study conducted with preterm infants hospitalized in the neonatal intensive care unit (NICU), the risk factors for THOP were being born before the 28th gestational week, having a low Apgar score at 5 minutes, and using aminophylline, dobutamine and morphine treatments.1 Although the authors did not present treatment data for infants with THOP in the results section, they stated in the discussion section that none of the newborns with THOP required L-thyroxine treatment. According to the results of studies involving mainly preterm infants with a gestational age over 30 weeks, THOP has no adverse effect on the developing brain and improves within postnatal 2 weeks.3 5 Current studies, including extremely preterm infants (under 28 weeks gestation), have shown that THOP harms the developing brain.5 According to our knowledge, prospective randomized trials for treating THOP are lacking. [...]there is controversy among clinicians about the indication for treating THOP. A recent retrospective study in our country suggested that clinicians tended to give levothyroxine treatment to the group with a median gestational age of 28 weeks, while levothyroxine treatment was not necessary for older preterm infants (median 31 weeks).4 Maneenil et al.1 did not present any data on the prognosis of untreated THOP infants born below 28 weeks of gestation (n: 17).