What Studies Say about Mirena Birth Control

I've recently been asked by countless women if I can point them toward sound research regarding IUD's. (Not so) coincidentally, I was contacted by a writer who recently wrote an article that discusses the research conducted with one form of IUD. I hope this guest blog piece is helpful for those of you searching for more facts about this relatively new birth control option for women.

 

What Studies Say about Mirena Birth Control

By: Alanna Ritchie

Making yourself aware of clinical trials and their results can help you determine whether a new birth control method is safe and effective. Many women are trying out intrauterine devices (IUDs), which are implanted in the uterus by a doctor and provide birth control for several years. You  can prepare yourself for your next doctor's visit by learning about one popular IUD , Mirena.

Studies Show Effectiveness

Two clinical trials with large population samples found that Mirena is quite effective in preventing pregnancy¹. The trials were conducted by Berlex Laboratories, a subsidiary of Bayer, and took place in Finland and Sweden. From 1982 to 1996, researchers evaluated data from both trials, which included a total of 1,169 women of child-bearing age using Mirena. Of the test subjects, 99 percent did not get pregnant.

The same trials revealed that after the device was removed, 80 percent of women desiring children were able to get pregnant within a year of using Mirena.

For women who use Mirena while breastfeeding, Bayer reports that there are no adverse effects, although milk production may be affected². Also, small amounts of the progestin hormone that Mirena releases can pass into breast milk, but this does not affect growth, health or development of nursing infants.

Studies Reveal Side Effects

One study documented a dangerous side effect known as device migration; this occurs when Mirena moves out of the uterus³. Although the manufacturer claims this does not happen often, a study by the Department of Radiology at the Ronald Reagan UCLA Medical Center noted that device migration was a "frequently encountered complication."

Once the device migrates, it can enter the pelvis, bladder, abdominal cavity or blood vessels, causing pain, infection and damage. This requires a physician to locate Mirena and perform surgery to remove the device.

Mirena's labeling information includes other side effects discovered during clinical trials⁴, including:

·         Bleeding or spotting between periods

·         Amenorrhea (missed periods)

·         Ovarian cysts

·         Abdominal or pelvic pain

·         Headache or migraine

·         Breast tenderness or pain

·         Vaginal discharge

·         Menorrhagia (heavier and prolonged period)

·         Depressed or altered mood

·         IUD expulsion

·         Ectopic pregnancy

IUD expulsion is experienced by around 5 percent of women who use Mirena and occurs when the device comes out on its own. When this happens, women may experience cramping, bleeding and discomfort during sex. Back-up birth control must be used until a new device is implanted.

Ectopic pregnancy is a rare, but possible side effect of Mirena that occurs when the egg is fertilized in the fallopian tubes or other locations outside of the uterus. The pregnancy usually cannot survive and can put a woman's life at risk. Complications can result in infertility.

Clinical trials reveal the effectiveness of and side effects associated with Mirena. Some of these studies were completed by the manufacturer, Bayer, who is facing lawsuits over Mirena’s serious side effects.

 

Food and Drug Administration. (2000, February 2). Mirena Executive Summary. Retrieved from www.accessdata.fda.gov/drugsatfda_docs/nda/2000/21-225.pdf_Mirena_Medr.pdf

Bayer. (2013, February 8). Important safety information about Mirena. Retrieved from http://www.mirena-us.com/having-mirena-placed/make-an-appointment-with-mirena.jsp

Boortz, H.; Margolis, D.; Ragavendra, N. & Katell, D. (2012, March). Migration of intrauterine devices: radiologic findings and implications for patient care. Radiographics, 32 (2): 335-52. doi: 10.1148/rg.322115068

Bayer HealthCare Pharmaceuticals. (2009, October). Mirena. Retrieved from http://labeling.bayerhealthcare.com/html/products/pi/Mirena_PI.pdf

 

 

Alanna Ritchie is a content writer for Drugwatch.com, specializing in news about prescription drugs, medical devices and consumer safety.