Objective: To evaluate how intrauterine and neonatal thyroid hormone deficiencies 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 months 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 used to assess attention, memory, and learning abilities
Results: Data from transcribed videotapes showed the study group was significantly less attentive and had longer reaction times than controls but did not differ on indices of sustaining attention or learning. Within thyroid-deficient groups, offspring of treated hyperthyroid mothers showed an atypical profile suggestive of hypervigilance.
Conclusion: A decreased fetal or maternal thyroid hormone supply in pregnancy is associated with infants' poorer attention and altered rates of information processing.