Hallow Dear, There are two types of intrauterine contraceptive devices: medicated and non medicated. In medicated devices, mostly progesterone is impregnanted in them. Progesterone is known to increase the weight; not loose it. Non-medicated devices have no effect on individual weight. If you are losing weight, please consult your physician for some unnoticed underlying disease like tuberculosis or hormonal dysfunction like Thyroid dysfunction. Accordingly you may have to take treatment. I hope this gives you some guidelines. Dr. Nishikant Shrotri