Maternal hypothyroxinaemia in early pregnancy is associated with reduced performance in reaction time tests in 5-to-6-yearold offspring

Abstract

s ingediend voor het Amsterdam Kindersymposium 2013 41 Maternal hypothyroxinaemia in early pregnancy is associated with reduced performance in reaction time tests in 5-to-6-yearold offspring Martijn J.J. Finken (1), Manon van Eijsden (2), Eva M. Loomans (2), Tanja G.M. Vrijkotte (3), Joost Rotteveel (1) (1) VUmc (2) GGD Amsterdam (3) AMC INTRODUCTION Overt hypothyroidism in pregnant women is associated with poorer neurodevelopment in their children. Findings from studies investigating the eff ect of less severe impairments in the maternal thyroid function on cognitive functioning in off spring are diffi cult to interpret for a number of reasons, including lack of objective cognitive tests, pre-school age at assessment, and small sample sizes. We tested whether normal variation in the maternal thyroid function was associated with scores on cognitive tests that assess basic attention and information-processing functions in off spring at school age. METHODS This study was part of the Amsterdam Born Children and their Development (ABCD) study, which follows a population-based cohort of mothers and children. Maternal serum free thyroxin (T4) and thyrotropin (TSH) were obtained at the end of the fi rst trimester. In off spring at the age of 5-6 years, cognitive functioning was tested, using a computerized assessment program. Data were complete for 1,765 mother-child pairs. RESULTS Maternal hypothyroxinaemia (ie, maternal free T4 in the lowest 10% of distribution) was associated with a 42.4 (95% confi dence interval: 21.4-63.4) ms slower response speed in the simple reaction time task. It was also associated with a decreased stability in response speed. The relations found persisted after adjustment for the family background and perinatal conditions. None of the outcomes was robustly related to the maternal TSH level. CONCLUSION Lower maternal free T4 concentrations at the end of the fi rst trimester predicted slower response speed and decreased stability in response speed in off spring at 5-6 years of age.