Relationship between maternal thyroxine levels during pregnancy and memory function in childhood

Abstract

Two investigations are reported into the memory functions of a group of subjects for whom information on maternal thyroxine (T 4) levels during pregnancy is available. The first study made when the subjects were aged 14–15 years examined forward and backward memory span. No relationship between maternal T 4 levels and capacity of the short-term store, measured as length of forward memory span, was found. Backward memory span, which involves performing a mental operation on the material held in store, was found to be associated with maternal T 4 level. The second study, made when the subjects were aged 16–17 years, found a relationship between maternal T 4 levels during pregnancy and memory for serial position. Findings are discussed in terms of the role of maternal thyroxine in fetal brain development.