Abstract

Introduction

Neural tube defects (NTDs) are major congenital malformations that require multidisciplinary management during the neonatal period and are associated with additional congenital anomalies and adverse neurodevelopmental outcomes. This study aimed to evaluate the perinatal characteristics and thyroid function tests (TFTs) of newborns with NTDs admitted to our neonatal intensive care unit (NICU) and to determine the frequency of hypothyroidism in this population.

Materials and Methods

This single-center retrospective study included neonates diagnosed with NTDs and admitted to a tertiary NICU between January 2019 and June 2024. TFT results obtained during the first year of life were evaluated. Demographic, clinical, and laboratory data were retrieved from the medical records.

Results

After exclusion of patients with missing data, 49 neonates were included. Of these, 30 (61.2%) were female and 19 (38.8%) were male. The mean gestational age was 37±3 weeks, mean birth weight was 2887±670 g, and mean maternal age was 27.5±6 years. Forty-three infants (87.8%) were delivered by cesarean section. Thirty (61.2%) were born at term and 19 (38.8%) were preterm. The most common NTD locations were the lumbar and lumbosacral regions. Hydrocephalus was the most frequent associated anomaly, affecting 27 infants (55.1%), and 20 underwent ventriculoperitoneal shunt placement. TFTs were performed within the first postnatal week in 25 infants. Among the infants evaluated during the first postnatal week, 5 (20.0%) had thyroid function test abnormalities consistent with hypothyroidism, corresponding to 10.2% of the entire cohort. All infants with hypothyroidism underwent surgery within the first week of life, and TFTs were obtained postoperatively. Levothyroxine treatment was initiated in three infants. None of the infants with normal initial TFTs developed hypothyroidism during follow-up.

Conclusion

In this study, TFT abnormalities consistent with hypothyroidism were more frequently observed in newborns with NTD than the reported population-based prevalence of congenital hypothyroidism. Because TFTs were obtained after surgery, postoperative factors, including povidone-iodine exposure, may have contributed to thyroid dysfunction. However, persistent hypothyroidism during follow-up in some patients suggests that additional etiological factors should also be considered.