Mirena (thing)

Mirena is the brand name of a relatively new IUD - IntraUterine Device for all of those who aren't acronym savvy - that combines a continuous low dosage of the hormone progestin with the traditional IUD. Traditionally the IUD simply uses the mysterious powers of copper and no hormones to prevent pregnancy – either by thickening the cervical mucous to the point that sperm cannot pass through it to the egg, creating an environment in the uterus hostile to sperm, or preventing implantation of a fertilized egg because of said disruption, or possibly all of these.

Unfortunately one of the main side effects to the traditional copper IUD is increased menstrual flow and cramping. Mirena addresses this problem using the synthetic hormone progesterone, progestin, which causes the uterine lining to thin and the cervical mucous to thicken, thus creating a lighter, less painful period. After several months, some users even report that their periods completely stop, much to their delight.

The IUD, which is shaped like a “T” and is about an inch and a half long, is inserted by a trained physician using a tube which is pushed through the opening of the cervix. The arms of the “T” fold down for easy insertion, and then spring open inside of the uterus. Small monofilaments hang out of the cervix and into the upper portion of the vagina for removal. The Mirena IUD has a shorter lifespan than the traditional IUD – but “shorter” is still a relative term since they can be kept in for up to 5 years (compared to 10-12 for a copper one) it is 99% effective in preventing pregnancy – comparable to sterilization. The IUD can be removed at anytime by a physician and fertility is returned to normal almost at once.

Complications/possible side effects include those for hormonal birth control, like weight gain, nausea, headaches, acne, and mood swings. Progestin alone doesn’t hold as many of the heart-related complications that combination estrogen and progesterone birth control has however, and so can be used (with relative safety) by smokers. IUDs are recommended for women who have already had a child, as there is a risk of accidental expulsion of the IUD which is higher for those who have never been pregnant (possibly because they’ve never had a foreign object floating around in their uterus). In addition there is also the possibility that the IUD may implant itself into the side of the uterus which might require surgery to remove, or it might even puncture the uterus, although since the big scandal about the Dalkon Shield manufacturers have become much more careful that this won’t happen.