Neurodevelopmental Outcome of Preterm Infants with Hypothyroidism

Abstract

Background: Hypothyroidism is one of the most common causes of preventable intellectual disability and is common in preterm infants. Some studies have reported that developmental delay is still high in these patients despite appropriate treatment. Objectives: This study aimed to investigate the short-term neurodevelopmental outcome of preterm infants with thyroid dysfunction. Methods: This cohort study included 50 preterm infants with thyroid dysfunction requiring levothyroxine treatment (case group) and 50 age- and sex-matched healthy preterm infants with normal thyroid tests (control group). The patients were followed, and Ages and Stages Questionnaires (ASQ) (including five domains) were filled out at 6 and 12 months to evaluate the short-term neurodevelopmental outcome. Results: There was no statistically significant difference in gestational age, sex, and birth weight between the two groups (P-values = 0.648, 0.756, and 0.866, respectively). A total number of 4 (8%) and 7 (14%) of the case group and 1 (2.85%) and 2 (5.71%) of the control group had a possible neurodevelopmental delay based on the low score in at least one domain of ASQ at 6 and 12 months of age (P-values = 0.321 and 0.222, respectively). Treated hypothyroidism was not significantly associated with higher impaired neurodevelopmental outcomes (P-value = 0.236, Odd Ratio: 2.686, 95% CI: 0.523 - 13.787). Conclusions: In this study, the risk of neurodevelopmental impairment in preterm infants with hypothyroidism was similar to that of healthy preterm infants. Thus, these findings may confirm the adequacy of levothyroxine replacement therapy in preventing neurodevelopmental delay.