Objective To ascertain iodine nutritional status of pregnant women and children in Shanghai since the implementation of Salt Iodine Content Standardin 2011. Methods By population proportion probability sampling,30 sub-districts(towns) were chosen,with one primary school was randomly sampled in each sub-districts(towns). And 50 students aged 8-10 in every school were randomly selected to test their urinary iodine and thyroid volume,and their household iodized salt concentration determined. And 20 pregnant wo...