Abstract
AIMS: Thyroid hormones (THs) play a vital role in neonatal development. The present study aimed to evaluate the association between thyroid function and bronchopulmonary dysplasia (BPD) incidence as well as neurodevelopment in extremely and very preterm infants. METHODS: This retrospective study involved 125 preterm infants born between 26 and 32 weeks of gestation from January 2020 to October 2025. Thyroid function tests were performed at 2 and 4 weeks after birth, and neurodevelopment was assessed using General Movements (GMs) at 36 weeks and 40 weeks of postmenstrual age (PMA). RESULTS: Among the 125 infants, 40 infants (32%) developed BPD; of these 40 infants, 27 and 13 infants were classified as grade 1 and grade 2 BPD, respectively. Notably, the grade 2 BPD group had significantly lower TH levels compared to both grade 1 BPD and non-BPD groups (P < 0.05). Additionally, the non-BPD and grade 1 BPD groups showed a tendency to exhibit better neurological development at 36 and 40 weeks PMA compared to the grade 2 BPD group, although this difference was not significant. CONCLUSIONS: Serial thyroid function monitoring during the first month of life may be useful in identifying extremely and very preterm infants who are most at risk of developing severe BPD (grade 2). Future intervention studies are needed to determine whether thyroid replacement therapy in this particular high-risk group may reduce the severity of BPD and potentially improve neurodevelopmental outcomes.