Psychomotor development of children from an iodine-deficient region.

OBJECTIVES To assess the psychomotor development of the progeny of women from a moderately iodine-deficient area for whom thyroid function during pregnancy was measured. STUDY DESIGN The development of 86 children was assessed by the Bayley Scale of Infant Development at 12, 18, and 24 months. RESULTS Maternal serum free thyroxine (FT(4)) levels in the first trimester of pregnancy were the major determinant of psychomotor development at 18 and 24 months. Children born from mothers with FT(4) levels <25th percentile (<10 pg/mL) had an OR of 2.1 for mild-to-severe delay. Furthermore, alterations in behavior were already observed at 12 months and were related to subsequent changes in development. Neonatal thyroid status did not influence development. CONCLUSIONS This study highlights the need to implement active measures of iodine supplementation periconceptionally and during pregnancy and lactation because the negative effects on development and behavior might be prevented through preemptive action.