Information on copper intrauterine devices.

There are two types of intrauterine devices available in the United States - the Paragard Copper IUD and the Mirena hormonal IUD. Both Paragard and Mirena are brand names and are the only brands that are approved for use in America. This article will discuss the Mirena IUD but here is more information on the Paragard copper IUD.

The Mirena IUD, or intrauterine device, is the brand name for a hormonal intrauterine device. Mirena Coil IUDs are manufactured and marketed by two companies: Berlex Laboratories, a pharmaceutical research company based in Montville, New Jersey, and Schering AG, a subsidiary of Bayer. (Berlex Laboratories is known for another birth control product Yasmin).

Mirena IUDs are referred to by several other names including levonorgestrel IUD (LNg) and progestin IUD.

The Mirena IUD works by killing or irreparably damaging sperm and obstructing it's ability to fertilize an egg. It does this by releasing levonorgestrel, also known as progestin.

Progestin is a synthetic substance which imitates the biological activity of the natural hormone progesterone. Progesterone can inhibit ovulation during pregnancy. Progestin was synthesized for, among reasons, suppressing ovulation for birth control.

Progestin, as contained in Mirena, accomplishes this in several different ways outlined below:

1) Mirena reduces the frequency of ovulation. Ovulation occurs during the menstrual cycle where the ovarian follicle releases an egg. Reduction of the times in which an egg is available to fertilize handicaps the sperm's opportunity for reproduction.

2) Mirena changes the consistency of cervical mucus. This change thickens the cervical mucus making the passage of sperm through the cervix much more difficult.

3) Mirena thins the endometrium, the lining of the walls of the uterus. It is thought that this reduces the chances of embryo implantation to the endometrium.

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