Thus , regardless of study design , iodine deficiency had a substantial impact on mental development .
Several review s and meta-analyses have examined the effects of iodine on mental development .
None focused on young children , so they were incomplete in summarizing the effects on this important age group .
The current systematic review therefore examined the relationship between iodine and mental development of children 5 years old and under .
Effects of maternal iodine supplementation during pregnancy.
Reduced maternal thyroid hormone concentrations during pregnancy can adversely affect fetal neurological development . In the context of national iodine supplementation programmes , concern has been expressed over the theoretical possibility that iodine supplementation during pregnancy might adversely affect fetal development as a result of maternal thyroid inhibition from the Wolff-Chaikoff effect . In a double blind controlled trial in five villages in Papua New Guinea , several measures of motor and cognitive function showed no significant differences at either age 11 or 15 years between those children whose mothers had received supplementary iodine during pregnancy and the control children whose mothers had received the placebo
Thus , regardless of study design , iodine deficiency had a substantial impact on mental development .
Several review s and meta-analyses have examined the effects of iodine on mental development .
None focused on young children , so they were incomplete in summarizing the effects on this important age group .
The current systematic review therefore examined the relationship between iodine and mental development of children 5 years old and under .