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Abstract

Cord blood thyroid-stimulating hormone (CB-TSH) measurement is a standard component of newborn screening for congenital hypothyroidism (CH). However, CB-TSH levels may be influenced by maternal and perinatal factors, potentially leading to false-positive results and unnecessary interventions. To evaluate the impact of maternal and perinatal factors on CB-TSH levels and to correlate elevated levels with neurodevelopmental outcomes during infancy. This prospective observational study included 150 neonates delivered at the Integral Institute of Medical Sciences. Detailed maternal history, perinatal events, and antenatal drug exposures were recorded. CB-TSH levels were measured at birth and analyzed using clinical cut-offs and quartiles. Neurodevelopmental assessments were performed at 3, 6, 9, and 12 months using standard developmental milestone checklists. Associations were analyzed using chi-square and Fisher’s exact tests. Elevated CB-TSH levels (≥6.6 mIU/L) were observed in 36.0% of neonates, although the screen-positive rate for CH (CB-TSH >20 mIU/L) was low at 1.3%. Significant associations were found between elevated CB-TSH and maternal hypothyroidism (25.0%), gestational diabetes mellitus (16.7%), and antenatal use of thyroxine or insulin (p = 0.025–0.033). Among perinatal factors, meconium-stained amniotic fluid (41.7%), birth asphyxia (12.5%), and NICU admission (22.9%) showed significant correlations with elevated CB-TSH. Mild delays in language and social domains were observed in infants with elevated TSH, although these did not reach statistical significance (p > 0.05). CB-TSH levels are significantly affected by maternal endocrine conditions and perinatal stressors. Despite a high prevalence of elevated TSH levels, the incidence of confirmed CH and neurodevelopmental delays was low. Careful interpretation of CB-TSH results is essential to avoid overdiagnosis and unnecessary clinical interventions.