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Updated: Jul 6, 2026
Transcutaneous Microcirculatory Imaging in Preterm Neonates
Published on: December 31, 2015
Exploring reference ranges for thyroid-stimulating hormone in neonatal screening tests for preterm infants: a 5-year
Xing Huang1,2, Fei Xiong1,2, Shulan Zhu1,2
1Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China.
Insights
Thyroid-stimulating hormone (TSH) levels vary in preterm infants based on gestational age, birth weight, and postnatal age. New reference ranges are needed for accurate congenital hypothyroidism screening in these vulnerable infants.
Area of Science:
- Neonatal screening
- Endocrinology
- Pediatric diagnostics
Background:
- Current thyroid-stimulating hormone (TSH) screening cutoffs are standardized for both term and preterm infants.
- This standardization may not accurately reflect the unique physiological variations in preterm neonates.
Purpose of the Study:
- To establish specific TSH reference ranges and cutoff values for preterm infants.
- To analyze these ranges based on gestational age (GA), birth weight (BW), and postnatal age (PNA).
Main Methods:
- Retrospective analysis of neonatal blood screening tests (NBST) from October 2017 to December 2022.
- Classification of preterm infants by GA, BW, and small-for-gestational-age (SGA) status.
- Determination of TSH percentiles (2.5th, 5th, 50th, 95th, 97.5th) and establishment of the 97.5th percentile as the screening cutoff.
Main Results:
- Significant disparities in TSH cutoff values were observed across different GA, BW, and SGA categories.
- In the first four weeks, preterm infants showed a dynamic TSH pattern, peaking in the third postnatal week.
- Small-for-gestational-age infants exhibited notably higher TSH levels (P < 0.05).
Conclusions:
- TSH levels in preterm infants are significantly influenced by GA, BW, and PNA.
- SGA infants require specific consideration due to elevated TSH levels.
- Condition-specific TSH reference ranges are crucial for enhancing the diagnosis and management of congenital hypothyroidism (CH).
Purpose:
Currently, the same thyroid-stimulating hormone (TSH) cutoffs are used for term and preterm infants. Our objective was to determine TSH reference ranges and cut-off values for preterm infants born at different gestational ages (GA), birth weight (BW), and postnatal age (PNA).
Methods:
A retrospective analysis was performed on preterm infants who received neonatal blood screening tests (NBST) between October 2017 and December 2022. Newborns were classified based on GA, BW, and small-for-gestational-age (SGA) status. For each category, the 2.5th, 5th, 50th, 95th, and 97.5th percentiles of TSH levels were determined. The 97.5th percentile was established as the cutoff value for TSH screening. TSH reference thresholds were then established for different PNA periods.
Results:
Infants were categorized based on GA, BW, and SGA status. Through this categorization, it was discovered that there were disparities in the cut-off values of TSH among different groups. In particular, during the first four weeks after birth in preterm infants, the 97.5th percentile TSH level (screening cutoff), one of the key indicators in NBST, shows a sequential trend of initial decline, subsequent rise, and final decrease, which peaked at 7.38 μIU/mL in the third postnatal week.
Conclusion:
TSH levels in preterm infants are influenced by GA, BW, and PNA, with SGA infants showing significantly higher TSH levels (P < 0.05). Developing condition-specific TSH reference ranges is essential for improving congenital hypothyroidism (CH) diagnosis and management.
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