Association of Certain Maternal and Neonatal Factors with Neonatal Thyroid-Stimulating Hormone Levels: Insights for Congenital Hypothyroidism Prevention.

Background: This study investigates the associations between certain maternal and neonatal factors and neonatal thyroid-stimulating hormone (TSH) levels. Understanding these associations may contribute to strategies for reducing the risk of congenital hypothyroidism. Methods: This cross-sectional study was conducted in Tehran in 2023 and included 1914 newborns. Data were collected from electronic health records. Peripheral blood samples were taken from the heel and placed on special filter paper for analysis. The data was analyzed using independent t-tests and unadjusted and adjusted linear regression at a 95% significance level using Stata software version 17. Results: The study included 1914 newborns, with 47.8% female and 81.4% having Iranian parents. Sixty percent were delivered via cesarean section, and 6.4% had a birth weight of less than 2500 grams. Additionally, 15% had mothers over 35 years old, and 38.7% reported parental consanguinity. neonates born via cesarean section had lower mean TSH levels, while those with a low birth weight (<2,500 grams) and those born to mothers over 35 years old had higher TSH levels. The crude linear regression analysis showed that older maternal age, low birth weight, and cesarean section delivery were significantly associated with neonatal TSH levels. After adjusting for covariates, multiple linear regression analysis confirmed the association between higher TSH levels and maternal age over 35 years, low birth weight, and cesarean section delivery. Conclusions: Our study has identified certain maternal and neonatal factors associated with neonatal TSH levels. Low birth weight, maternal age over 35 years, and mode of delivery emerged as significant variables in this association.