What Is Levonorgestrel Used For?

Levonorgestrel is a synthetic progesterone, a hormone that is naturally produced in a woman's body that regulates ovulation. Commonly found in many forms of birth control and emergency contraceptives, levonorgestrel is also being studied to see if it will prove useful in menopausal hormone replacement therapies in women.

What Is Levonorgestrel?

• Levonorgestrel is a synthetic hormone that is produced in a laboratory setting. It mimics the action of a natural hormone called progesterone, which regulates and plays a role in bringing on a woman's monthly menstrual period. It also enables a fertilized egg to be able to grow into a fetus during pregnancy.

  When progesterone levels remain high, a woman's ovaries do not ovulate and she experiences no menstrual period. Levonorgestrel, since it mimics the action of progesterone, also prevents ovulation in women.

Contraceptive Pills

• There are many contraceptive, or birth control, pills that contain levonorgestrel. In contraceptives, levonorgestrel is usually paired with a synthetic estrogen to obtain maximum results. These synthetic hormones prevent pregnancy by preventing ovulation from occurring. By preventing ovulation, there is no egg for sperm that enter the vagina to fertilize. Thus, no pregnancy can occur.

  Birth control pills that contain levonorgestrel include Alesse, Aviane, Levlite, Levlen, Levora, Nordette, Tri-Levlen, Triphasil, Trivora and Seasonale.

Emergency Contraceptives

• Levonorgestrel is used in emergency contraceptives as well. Emergency contraceptives are designed for occasional use when a woman has accidental unprotected sex or finds herself at risk for getting pregnant.

  The most popular brand of emergency contraceptive in the United States is Plan B. The difference between emergency contraceptives (also known as the "morning-after pill") and regular contraceptives is that emergency contraceptives contain much higher doses of synthetic hormones than do birth control pills that are taken daily.

  Emergency contraception, however, does work in the same way that birth control pills work: by preventing ovulation.

Mirena IUD

• Instead of taking pills every day, some women choose to have an IUD, or intrauterine device, inserted into their uterus. This device provides long-lasting birth control for up to five years. The name brand for levonorgestrel-containing IUDs in America is Mirena.

  The IUD is a small plastic device that is inserted through the cervix into the body of a woman. The device contains levonorgestrel that is very slowly released directly into the uterus over the time frame the woman keeps the IUD inside of her.

  The levonorgestrel in Mirena is combined with a synthetic estrogen to prevent ovulation and pregnancy.

Norplant

• Norplant is a series of six tiny tubes that can be implanted in a woman's arm and is effective at preventing pregnancy for up to five years. The tiny tubes contain levonorgestrel along with a synthetic estrogen.Over the course of five years, the tubes release small amounts of the synthetic hormones and prevent pregnancy by preventing ovulation.

Use in Menopause

• Studies are being conducted to determine levonorgestrel's use in non-contraceptive applications. The primary use being explored is for levonorgestrel as a hormone replacement medication to help alleviate the symptoms of menopause in women.

  If these studies prove levonorgestrel to be safe and effective, it is possible that levonorgestrel will be used in the near future in hormone-replacement therapies, or HRTs.