Dear Sheeba,Copper T can not lead to increase in weight.You can just check its position by feeling the thread any time after periods.check it once or twice in a month.Normally it is good for about 3 years in most of the cases,still it depends upon the type of it.In rare cases is can be misplaced and migrate,so do not worry.Look for other reasons for weight gain like
thyroid,poor diet,lack of exercise etc.bye and take care.