The IUD is a small, T-shaped device that's placed into your uterus by your nurse practitioner or your physician, and depending on the type of IUD that you choose, it can be effective for five to ten years after the unit has been placed.
The side effect profile for the IUD changes between the two different types of IUDs. The copper IUD has no hormones in it, so you'll get your periods monthly, just as you would if you were not using any birth control. The side effects for that IUD include cramping and bleeding with your periods that may be a little bit more than what you would anticipate with your normal cycle. Your periods may be a little bit longer as well.
The Mirena IUD is an IUD that has progesterone impregnated in the unit itself. This form of contraception is also as effective as the IUD that I just described earlier. The drawback for this form of birth control is that you may have some irregular bleeding for the first three to six months that you have this unit placed. The truth is most patients do not have this side effect for longer than two to three months, and it has the added benefit of stopping your periods over the interval that you're using this unit. If you're someone that has heavy and painful periods or your periods are not regular, this may be a better IUD option for you.
If you're not certain about which option is better for you, you should call your doctor or nurse practitioner and discuss in detail which IUD is a better option for you.