Transient hypothyroxinemia without elevated thyroid-stimulating hormone (TSH) levels is common in @entity3465 , especially in very-low-birth-weight (VLBW) @entity1 . The @entity1685 ( @entity1685 ) has been seen as a "benign" condition not requiring medical treatment. However, some recent large observational studies have revealed a relationship between @entity1685 and abnormal neurodevelopment. Furthermore, one study showed @entity1685 had twice the risk of brain echolucency, which was the best predictable @entity245 , than the premature @entity1 with normal or higher @entity1955 levels. The relationships among @entity1685 , illness severity, and @entity245 remain unclear. We propose a hypothesis that @entity1685 is associated with abnormal ultrasound and illness severity. We studied 54 @entity1 who were admitted more than 14 days at our neonatal intensive care unit (NICU) with a birth weight <2000 g from March 1999 to March 2000. The infants received serum @entity1955 (T4), free-T4, and TSH measurement during the first weeks of life. Most of them had serum @entity1955 levels measured at approximately 2 weeks of age. The @entity1 enrolled in the study were examined by at least 1 of 3 cranial ultrasounds during the first weeks of life, illness severity evaluation according to the neonatal therapeutic intervention scoring system (NTISS) score, as well as NICU hospital stay period. @entity1 were classified as @entity1685 by T4 value <5.3 microg/dL (68 nmol/L), which is 2.6 SD below the mean for term @entity1 in Massachusetts, without elevated TSH value (<20 microIU/mL). After adjusting for some confounding factors, such as gestational age, birth weight, duration of mechanical ventilation, @entity1 with @entity1685 were associated with abnormal cranial ultrasound, illness severity, and lower 1-minute Apgar score. In our studies, @entity1685 was related with @entity75 , @entity221 , and lower Apgar score at 1 minute. Does early @entity1955 intervention improve the prognosis and @entity245 ? This question requires further investigation.

Transient hypothyroxinemia of XXXX is associated with abnormal cranial ultrasound and illness severity.

@entity1 :: ('9606', 'Species') :: ['Infant', 'infants'] @entity3465 :: ('MESH:C536271', 'Disease') :: ['prematurity'] @entity75 :: ('MESH:D001927', 'Disease') :: ['brain ultrasound anomaly'] @entity245 :: ('MESH:D002658', 'Disease') :: ['neurodevelopmental dysfunction'] @entity1955 :: ('MESH:D013974', 'Chemical') :: ['thyroxine'] @entity1685 :: ('MESH:C563551', 'Disease') :: ['transient hypothyroxinemia of prematurity', 'THOP'] @entity221 :: ('MESH:D005334', 'Disease') :: ['neonatal illness']
@entity3465 :: (MESH:C536271,Disease) :: ['prematurity']
