<b>Frequency of Congenital Hypothyroidism in Term Neonates at Dr. Akbar Niazi Teaching Hospital, Islamabad</b>

Background: Congenital hypothyroidism (CH) is one of the most common preventable endocrine disorders in neonates, associated with irreversible neurodevelopmental impairment if undiagnosed. While most affected infants are asymptomatic at birth, early biochemical screening enables timely treatment. Global prevalence is approximately 1 in 3,000–4,000 live births, but higher rates have been reported in South Asia, where systematic newborn screening remains limited. Objective: To determine the frequency of congenital hypothyroidism in term neonates at a tertiary care hospital in Islamabad and to characterize clinical and biochemical features of affected infants. Methods: This descriptive cross-sectional study was conducted at Dr. Akbar Niazi Teaching Hospital, Islamabad, between November 2024 and April 2025. A total of 125 term neonates were consecutively enrolled. Venous blood samples collected between days 5–7 of life were analyzed for thyroid-stimulating hormone (TSH) and total thyroxine (T4) using chemiluminescence immunoassay. Neonates with TSH >10 µU/mL underwent confirmatory testing. Data were analyzed using descriptive statistics, chi-square, t-tests, and odds ratios with 95% confidence intervals. Results: The mean gestational age was 38.7 ± 1.4 weeks, with 52.8% males. Initial screening identified 13 neonates (10.4%) with elevated TSH. After confirmatory testing, 7 neonates (5.6%) were diagnosed with CH, 4 (3.2%) with transient hypothyroidism, and 2 (1.6%) remained suspicious. Affected neonates had significantly higher TSH (22.9 ± 8.6 µU/mL) and lower T4 (4.1 ± 0.9 µg/dL) compared to normal infants (p<0.001). More than half of CH cases (57.1%) were asymptomatic. Conclusion: The prevalence of CH among term neonates in this setting exceeded global averages, with most cases clinically silent. These findings underscore the urgent need for nationwide newborn screening programs in Pakistan.