The effect of abnormal intrauterine thyroid hormone economies on infant cognitive abilities

Objective: To evaluate how intrauterine and neonatal thyroid hormone defici encies affect infant cognitive abilities. Method: 26 infants with intrauterine or neonatal thyroid hormone deficiency and 20 full-term infants with normal thyroid economies were studied at 6 m onths of age or corrected age. Reasons for thyroid hormone deficiency were maternal hypothyroidism, maternal hyperthyroidism treated with antithyroid medication, congenital hypothyroidism, and low-risk prematurity. A computer -generated task during which infants' eye-movements were videotaped was use d to assess attention, memory, and learning abilities Results: Data from transcribed videotapes showed the study group was signif icantly less attentive and had longer reaction times than controls but did not differ on indices of sustaining attention or learning. Within thyroid-d eficient groups, offspring of treated hyperthyroid mothers showed an atypic al profile suggestive of hypervigilance. Conclusion: A decreased fetal or maternal thyroid hormone supply in pregnan cy is associated with infants' poorer attention and altered rates of inform ation processing.