Perinatal Factors Associated With Congenital Hypothyroidism in Very Low Birth Weight Infants: A Retrospective Cohort Study.

This retrospective cohort study analyzed perinatal risk factors for congenital hypothyroidism (CH) in 1073 very low birth weight (VLBW) infants (<1500 g) admitted to a neonatal intensive care unit. The overall CH incidence was 6.0% (65 cases), with significantly higher rates in extremely low birth weight (ELBW) infants (11.1%) and extremely preterm infants <28 weeks' gestation (11.3%). Multivariate analysis identified maternal thyroid disease (odds ratio [OR]: 2.12, 95% confidence interval [CI]: 1.10-4.12) and patent ductus arteriosus (OR: 2.25, 95% CI: 1.33-3.79) as independent risk factors, while higher birth weight showed a marginally protective effect (OR 0.998, 95% CI: 0.997-1.000). The elevated CH incidence among extremely preterm infants and those with lower birth weights highlights the needs for dynamic thyroid monitoring in VLBW populations, particularly when maternal thyroid disease is present. These findings justify risk-stratified surveillance protocols to facilitate early detection and optimize clinical management in high-risk neonates.