Over 12 million women world wide, 2 million of them in the United States use the Mirena IUD, which, unlike traditional IUDs actually releases a low level of female hormones directly into the uterus to prevent a woman falling pregnant.
This device though, like all other methods of birth control is not without its shortcomings and possible side effects:
It is advised that the Mirena should be used by women who already have one child; who have already undergone a pregnancy and childbirth. The Mirena website itself advises this.
Also women who have a pelvic infection or who are prone to infections easily cannot use a Mirena IUD.
Women with certain cancers also cannot have them put in. There is a very small chance that women who use this form of contraception could develop pelvic inflammatory disease.
The reason that it is advised that the strings of the device be checked routinely is that is some cases the Mirena can attach to the wall of the uterus or even go through it, causing some very serious problems which in cases may require surgery. It has sometimes been seen that the device may pierce the uterine wall and go through to the walls as well is some rare cases.
Weight gain is another known and reported side effect of the device. Although the website says minor weight gain, some women have reported up to 25 pounds of weight gained over a period of two years, however this is not clinically proven so it is likely that the anecdotal evidence may also owe itself to other reasons.
Many women report pain when this IUD inserted, which may range from mild to quite severe. Also side effects such as cramps, spotting, dizziness or headaches, and even pain during sex have been reported by some women.
It is very important that the healthcare provider or doctor who inserts this device is experienced in this; incorrect insertion can be very problematic.
Also sometimes the strings of the IUD can be felt during sexual intercourse which can be uncomfortable or not, depending upon your point of view. Sex can also be slightly painful in some cases and in some cases women reported a decreased libido or sex drive. Breast tenderness and pain is also not uncommon.
Acne is another problem that some women report from the use of this IUD device. Several women have reported acne breakouts resulting from the insertion of the Mirena IUD.
Mirena IUD has not been around long enough for us to know clearly the effect it has on long term fertility, and this is another point to consider if you are considering this form of contraception.