Mirena is one of two types of intrauterine devices approved for the use of pregnancy prevention. The Mirena IUD or coil is also called the hormonal IUD because it is releases the progestin hormone, levonorgestrel, in addition to being shaped in the same manner as the other approved IUD, which is made with copper. Mirena is often recommended for women who have had at least one child and who have a normal cervix and uterus shape.
Device Shape
The Mirena coil is a T-shaped plastic frame intrauterine device that releases low doses of levonorgestrel. The frame is soft and flexible. At the base of the T is a long string. Once the device is inserted into the uterus, the medical professional will trim the string to prevent it from interfering with intercourse, tampon use and to prevent it from easily being withdrawn.
Insertion
The Mirena coil must be carefully placed into a woman's uterus. The device should be placed within seven days of the woman's period. During the office visit, the medical practitioner inserts a speculum into the vagina. The Mirena coil comes with a special device that helps with placement. The practitioner loads the IUD into the insertion device then inserts the device into the cervix. Once the device is in place, the practitioner releases a mechanism, which allows the IUD to spring into place. Once the IUD is in place, the practitioner trims the long string.
Function
When the IUD is placed into the uterus, it releases a small amount of the progestin, levonorgestrel on a continuous basis. When this hormone reaches the uterus, it causes a thickening of cervical mucus, making it more difficult for sperm to enter the cervix, and also inhibits sperm from reaching and fertilizing an egg. Additionally, Mirena causes a thinner uterine lining, making it more difficult for a fertilized egg to attach and thrive. A thinner lining also results in a lighter menstrual period. Once the IUD is in place, it can remain for five years without needing to be replaced, according to Planned Parenthood.
Benefits
According to the American Congress of Obstetricians and Gynecologists about one out of 1,000 women who use the Mirena coil will become pregnant, making it one of the most effective forms of birth control available. Women find the device to be very convenient because nothing more has to be done once the IUD is in place. Physical activity does not cause the IUD to fall out of place, sexual intercourse and tampon use do not have any impact on the IUD, and no back-up method of birth control is necessary. Some women may have diminished pain and bleeding during menstruation.
Side Effects
Shortly after the insertion of the Mirena coil, a woman may have some mild cramping and spotting due to the procedure itself. This should resolve within a day or two, but it can persist as long as a few weeks. Some women may experience an increase in vaginal discharge as the body gets used to the foreign device, but this improves within a month or two.
More serious side effects of the Mirena coil are rare, according to the American Congress of Obstetricians and Gynecologists. Expulsion can occur if the IUD is pushed out of the uterus into the vagina. This is most likely to occur during the first year of use, but about 5 percent of users have this side effect. The IUD can also pierce the wall of the uterus during insertion, called perforation. This is very unlikely. About one out of every 1000 women using the IUD will develop an infection of the uterus or fallopian tubes.
