Some people think that breastfeeding will provide adequate contraception. It won't. You can get pregnant without ever having another period after you've had a baby and start breast feeding.
If you know you want to get pregnant again, a long-term, reversible contraceptive is best. If you want something reliable until you're ready to try and get pregnant again, something like the IUS is best. Plus, you can forget about your contraception and concentrate on your new baby until you decide to try for another.
To find out more about IUS, visit this page - IUS method of contraception