Background: To evaluate whether thyroid-stimulating hormone (TSH) by newborn screening (NBS) at birth and at discharge can be surrogate markers for neurodevelopmental impairment (NDI) in extremely preterm infants.
Methods: The population cohort enrolled infants born <29 weeks' gestation in 2008 - 2020 in southern Taiwan. Infants with a maternal history of thyroid disorders and infants who required thyroxine supplementation during hospitalization were excluded. TSH levels by NBS at birth and at term-equivalent age (TEA)/discharge were respectively categorized into the lowest quartile, the interquartile range, and the highest quartile, which were correlated to NDI outcomes.
Results: Among 392 patients with paired TSH data, 358 (91%) were prospectively followed until corrected age 24 months. At birth, infants with lowest-quartile TSH had higher NDI risks (OR 2.3, 95% CI 1.3 - 4.1, P = 0.004) compared to infants with interquartile-range TSH. Conversely, by TEA/discharge, infants with highest-quartile TSH had increased NDI (OR 1.9, 1.0 - 3.4, P = 0.03). By paired TSH categories, infants persistently in the lowest TSH quartile (48%, aOR 4.4, 1.4 - 14.5, P = 0.01) and those with a shift from interquartile range to the highest quartile (32%, aOR 2.7, 1.0 - 7.4, P = 0.046) had increased NDI risks compared with the reference with consistent interquartile-range TSH.
Conclusions: Extremely preterm infants persistently in the lowest-quartile TSH level at birth and at discharge had the highest NDI risk. TSH quartile levels by NBS may serve as a population surrogate biomarker for assessing NDI risks in infants born extremely preterm.
Keywords: Extremely preterm; Neurodevelopmental Outcome; Newborn screening; Thyroid-stimulating hormone.