Swedish Iodine in Pregnancy and Development in Children (SWIDDICH) Study

THE ULTIMATE GOAL of this project is to answer the question "In MILD IODINE DEFICIENCY (ID), should a tablet with vitamins and minerals, including 150 μg iodine/day be administered to pregnant women with a normal diet, to attain a normal cognitive development of the fetus or is there no cognitive deficit from mild ID and no extra iodine is needed?". To answer this question, the investigators planned a randomized, placebo-controlled trial of micronutrient supplementation during pregnancy in Sweden (SWIDDICH) with the follow-up of childrens' COGNITIVE DEVELOPMENT at 18 months, 3.5, 7 and 14 years. Iodine deficiency (ID) is associated with thyroid morbidity and, especially in children, with impaired cognitive development. Sweden introduced iodine fortification of table salt 1936 and mental retardation due to severe ID is eradicated. Is mild ID during pregnancy also eradicated? If not, is this of importance? A national study performed by the investigators in 2007 showed iodine sufficiency in general population, but there are no pregnancy data. Local studies have raised concerns for mild ID during pregnancy in Sweden and a trans-sectional national study is currently ongoing. The burning question for Sweden and the whole world is: is mild ID during pregnancy of importance for the developing brain of the fetus? Two large observational studies have shown association between mild ID during pregnancy and lower verbal IQ or educational performance at school-aged children. The world needs a randomized placebo-controlled trial (RTC) comparing the cognitive outcome in children exposed to mild ID during fetal life with children exposed to normal iodine levels during fetal life. Our HYPOTHESIS is that pregnant women in Sweden have mild ID and that children exposed to mild ID during fetal life have a lower cognitive development, compared to children to mothers taking daily tablet with vitamins and minerals, including 150 ug iodine during pregnancy. The MAIN AIM of the SWIDDICH t