The best indicator for monitoring the impact of Iodine Deficiency Disorders control programme is :
Prevalence of goiter among school children
Urinary iodine levels among pregnant women
Neonatal Hypothyroidism
Iodine level is soil
Neonatal hypothyroidism is a sensitive pointer to environmental iodine deficiency and thus can be an effective indicator for monitoring the impact of the programme. Ref: Park's Textbook Of Preventive And Social Medicine By K. Park, 19th Edition, Page 426; Park's Textbook Of Preventive And Social Medicine By K. Park, 18th Edition, Page 467