On an educational trip to Uttarakhand, Ketki

On an educational trip to Uttarakhand, Ketki and her friends observed that many local people were having swollen necks. Please help Ketki and her friends to find out the solutions to the following questions.
(i) Which probable disease are these people suffering from? (ii) How is it caused?
(iii) What effect does this condition haveon pregnancy?

(i) The people are suffering from the goitre disease.
(ii) Goitre is caused by deficiency of iodine and the consequent hypothyroidism.
(iii) It leads to defective development of foetus and birth of child with cretinism.