Early postnatal changes in thyroid-stimulating hormone and subsequent neurodevelopment in preterm infants.

Area of Science:

• Neonatal Medicine
• Neuroscience
• Endocrinology

Background:

• Thyroid hormones are vital for fetal brain development.
• Preterm infants often have immature hypothalamic-pituitary-thyroid (HPT) axes, leading to thyroid dysfunction.
• Atypical thyroid patterns in preterm infants are associated with neurodevelopmental risks.

Purpose of the Study:

• To investigate if thyroid hormone trajectories in preterm infants predict neurodevelopmental outcomes at two years.
• To explore the neural correlates of these thyroid patterns using diffusion tensor imaging (DTI).

Main Methods:

• Prospective cohort study of 222 preterm infants (≤32 weeks gestation).
• Serial thyroid function tests (TSH) at 1-2 weeks and term-equivalent age/discharge.
• Neurodevelopmental assessment (BSID-III) and DTI at two years corrected age.
• Logistic regression with inverse probability of treatment weighting to analyze TSH trajectories and neurodevelopmental impairment (NDI).

Main Results:

• Infants with NDI had higher TSH at birth and peak hospitalization levels.
• Cross-sectional TSH quartiles did not independently predict NDI.
• Persistently low or decreasing TSH trajectories were associated with significantly lower odds of NDI (OR 0.24-0.23).
• Altered brain network centrality in fronto-limbic regions was observed in infants with higher neonatal TSH.

Conclusions:

• Persistently low or decreasing TSH trajectories in preterm infants are linked to reduced odds of neurodevelopmental impairment.
• Altered thyroid function and HPT-axis adaptation may contribute to atypical brain connectivity and neurodevelopmental outcomes.
• Serial TSH monitoring can help characterize risk and inform clinical management for preterm infants.