J.F.
After I had my second child (who is 7 months old) I had the Mirena IUD inserted. So far so good. It lasts 5 years and it is not permanent so if you change your mind and want to have another child you can have it removed at any time. I have not noticed any side effects from it. There is another IUD on the market that lasts 10 years. I would ask your doctor about all options.