Birth Control Options for Women - Intrauterine Devices (IUDs)

IUDs in general have the following advantages:

The IUD is more effective than OCs at preventing pregnancy and it is reversible. Once it is removed, fertility returns. (In spite of outdated concerns, studies have found no adverse effects on fertility with the current IUDs.)
Unlike the pill, there is no daily routine to follow.
Unlike the barrier methods (spermicides, diaphragm, cervical cap, and the male or female condom), there is no insertion procedure to cope with before or during sex.
Intercourse can resume at any time, and as long as the IUD is properly positioned, neither the user nor her partner typically feels the IUD or its strings during sexual activity.
It is the least expensive form of contraception over the long term.

There also additional advantages, depending on the specific IUD:

The progestin-releasing LNG-IUS (Mirena) is now considered to be one of the best options for treating menorrhagia (heavy menstrual bleeding). Some studies suggest it might help avoid hysterectomy in 80% of cases. Note: irregular break-through bleeding can occur for the first six months. It may even be appropriate and protective for women with uterine fibroids.
The copper-releasing IUDs do not have hormonal side effects and may help protect against endometrial (uterine) cancer.

Disadvantages and Complications of Specific Intrauterine Devices

The insertion procedure can be painful and sometimes causes cramps, but for many women it is painless or only slightly uncomfortable. Patients are often advised to take an over-the-counter painkiller ahead of time. They can also ask for a local anesthetic to be applied to the cervix if they are sensitive to pain in that area. Occasionally a woman will feel dizzy or light-headed during insertion. Some women may have cramps and backaches for a day or two after insertion, and others may suffer cramps and backaches for weeks or months. Over-the-counter painkillers can usually moderate this discomfort.

Menstrual Bleeding with the Copper T IUD. Both IUD forms have effects on menstruation, although they differ significantly by type:

Copper releasing IUDs can cause cramps, longer and heavier menstrual periods, and spotting between periods. Prescription medications are available to control the bleeding and pain, which, in any event, usually subside after a few months.
Progestin-releasing IUDs produce irregular bleeding and spotting during the first few months. Bleeding may disappear altogether. (This characteristic, particularly with the LNG-IUS is a major advantage for women who suffer from heavy menstrual bleeding but may be perceived as a problem for others.)