Association Between Newborn Thyroid-Stimulating-Hormone Concentration and Neurodevelopment and Growth: a Systematic Review.

Iodine nutrition during pregnancy can affect newborn thyroid-stimulating-hormone concentration (TSH). Associations of newborn TSH with the neurodevelopment and growth of children are inconsistent. The aim of the study was to systematically review the literature on the associations between newborn TSH and childhood neurodevelopment and growth. Databases including PubMed, Scopus, CINAHL, Embase, PsycINFO, WHO, and Iodine Global Network were searched for eligible studies. Seventeen studies were included. Neurodevelopment was assessed using different tools in children aged 1-12 years of age. The associations between newborn TSH and cognitive development were negative in studies from iodine deficient populations, while a null association was found in studies from iodine sufficient populations. A null association between TSH and psychomotor development was observed regardless of iodine status of the study populations. There was no evidence of an association between newborn TSH and child anthropometry, but evidence of negative association was found between newborn TSH and birthweight. Although the associations between newborn TSH and neurodevelopment may differ based on the iodine status of populations, most of the included studies did not adjust for the key confounders and had a small sample size. Quality data-linkage studies that utilize newborn TSH data from newborn screening with adequate adjustment for potential confounders are warranted to better understand the relationship between newborn TSH and neurodevelopment and growth in children. CRD42020152878.