NEW YORK, May 4: Mothers who are mildly iodine deficient are more likely to have children who perform poorly in spelling, grammar and literacy, according to a new study from Australia. Severe iodine deficiency during pregnancy is known to cause serious mental disabilities in children, but researchers examined the test scores of nine year olds whose mothers were only slightly iodine deficient during pregnancy and found the kids performed between 6 percent and 10 percent worse than peers born to mothers with sufficient iodine. (agencies)