Abstract
Objective: To determine the frequency of congenital hypothyroidism (CH) among term neonates born at a tertiary care hospital in Karachi, Pakistan.
Methodology: This descriptive, cross-sectional study was conducted at the Department of Pediatrics at Memon Medical Institute Hospital, Karachi, Pakistan, from October 2024 to March 2025. A total of 114 neonates born at gestational age between 37-42 weeks and weighing between 2.50 and 3.50 kg were analyzed. Neonates with thyroid-stimulating hormone (TSH) levels ≥20 mIU/L were labeled as having CH. Data were analyzed using SPSS 26.
Results: Out of 114 newborns, 64 (56.1%) were male. The mean gestational age, and birth weight were 38.6±1.15 weeks, and 2.72±0.22 kg, respectively. The mean TSH level was 13.31±8.84 mIU/L, while CH was identified in 11 (9.6%) newborns. A statistically significant association was observed between family history of hypothyroidism and neonatal CH (36.4% vs 12.6%, p=0.036). Pearson’s correlation analysis revealed no significant correlation between gestational age and serum TSH levels (r=-0.026, p=0.783), or between birth weight and serum TSH levels (r =-0.103, p=0.278).
Conclusion: Congenital hypothyroidism was identified in 9.6% of healthy term neonates. It was significantly more common among newborns with a family history of hypothyroidism.

Key words: Birth weight, gestational age, hypothroidism, neonate, thyroid-stimulating hormone.