Maternal thyroid dysfunction and neuropsychological development in children

Context Thyroid hormones are essential for fetal brain development. The potential effects of maternal gestational thyroid dysfunction on offspring neuropsychological development remain inconclusive. Objective This work aimed to estimate effects of maternal thyroid dysfunction during pregnancy on offspring neuropsychological development in the first 2 years. Methods We prospectively examined 1903 mothers and their children from the Shanghai Birth Cohort. Thyroid hormones were assessed at about 12 gestational weeks. Maternal thyroid function was classified into 7 categories: euthyroid, overt/subclinical hyperthyroidism, overt/subclinical hypothyroidism, hyperthyroxinemia, and hypothyroxinemia. Neuropsychological development was assessed by the Ages and Stages Questionnaire at age 6 months, and Bayley Scales at age 24 months. Results Compared with children of euthyroid mothers, maternal overt hypothyroidism was associated with 7.0 points (95% CI, 1.7-12.4) lower scores in personal-social domain in girls aged 6 months, 7.3 points (95% CI, 2.0-12.6) lower in motor domain, and 7.7 points (95% CI, 1.1-14.2) lower social-emotional scores in boys at age 24 months; maternal subclinical hypothyroidism was associated with 6.5 points (95% CI, 1.0-12.1) poorer social-emotional domain in boys at age 6 months, and 7.4 points (95% CI, 0.1-14.8) poorer adaptive behavior domain in boys at age 24 months; maternal hypothyroxinemia was associated with 9.3 points (95% CI, 3.5-15.1) lower motor scores in boys at age 24 months; and maternal subclinical hyperthyroidism was associated with 6.9 points (95% CI, 0.1-13.7) lower language scores in girls at age 24 months. Conclusion Maternal overt hypothyroidism, subclinical hypothyroidism/hyperthyroidism, and hypothyroxinemia during early pregnancy were associated with weakened neuropsychological development in infancy, and some effects may be sex specific.