Neurodevelopment of preterm infants born at 28 to 36 weeks of gestational age: the role of hypothyroxinemia and long-term outcome at 4 years

Context: Hypothyroxinemia in premature neonates may affect long-term neurodevelopment. Objective: This study aimed to examine the effects of hypothyroxinemia of the newborn preterm infants born at 28–36 weeks of gestational age (GA) on the neurodevelopment at 4 years of age. Patients: Prospective observational cohort study conducted in Madrid, Spain. Forty-six preterm infants were included in the study. Main Outcome: The effects of the exposure to neonatal hypothyroxinemia on mental development were examined. Results: Using regression analyses we found that neonatal T4 had a positive association with general cognitive index and Verbal index, and neonatal FT4 with general cognitive and Memory indexes at 4 years of age. Conclusions: The exposure to hypothyroxinemia during the neonatal period of late preterm infants may play role in neurodevelopmental delays. Higher T4 level means a trend to higher indexes and low T4 level means a lower neurodevelopmental indexes at 4 years of age.