Mirena and Breast Cancer: Is there a Link?

An intrauterine device (IUD) called Mirena can prevent conception for up to 7 years. It functions by releasing the progestin hormone levonorgestrel.

As a result, Mirena might not be the ideal option if you have a history of progestin-sensitive breast cancer. However, it’s a really secure and wise decision for the majority of women.

Mirena is not the only birth control pill that has been linked to breast cancer. Your risk of breast cancer may slightly increase if you use any hormonal contraception.

This is so because certain breast cancers are fueled by the hormones progesterone and estrogen.

Man-made (synthetic) versions of one or both of these hormones are present in hormonal birth control. The hormone in Mirena, progestin, is a synthetic version of progesterone.

However, there is no need to panic. It is because research has suggested a very small chance of people getting breast cancer through Mirena.

Association between Mirena and Breast Cancer:

Numerous studies have looked into the connection between both the risk of breast cancer and combination birth control tablets, which contain synthetic versions of the hormones progesterone and estrogen.

The hazards of progestin-only birth control, such as the Mirena IUD, have received less study.

Progestin-only birth control may not increase your risk of breast cancer, according to some studies.

Still, according to a large study, it was found:

• The risk of breast cancer was quite less in the general population as compared to women aged 30 years to 39 years who utilized intra-uterine devices
• The general population’s risk of breast cancer was somewhat greater than that of women who used IUDs with levonorgestrel (the hormone Mirena) aged 40 to 54.
• The risk of breast cancer was not affected by how long a woman used Mirena
• The risk of breast cancer was also not affected by the age of women who used this type of IUD or women who do not.

What does the research say about this?

Women who use the Mirena IUD may be at risk for developing breast cancer, according to the FDA’s latest labeled data, which reads: [Ref]

Because some breast cancers are hormone-sensitive, hormonal contraception should not be utilized by women who have, have had, or fear they may have breast cancer.

The label adds that the results of the research studies on the elevated risk are not conclusive and offers the following advice:

“Observational studies evaluating the risk of breast cancer associated with the use of an LNG-releasing IUS do not provide convincing evidence of increased risk,” the study concluded.

Studies that suggest a link between Mirena and Breast cancer

There are a bunch of studies that suggested a small link between breast cancer and Mirena.

Study of 2017 [ref]

A more current evaluation was released by Post Reproductive Health in 2017. It was mentioned that the advantages of contraceptives may outweigh the dangers.

Also, the chance of developing breast cancer which hormonal contraception induces is rather low. Again, the evaluation stated that safety should not be inferred from limited information.

Study of 2016 [ref]

Breast cancer incidence was not linked to progestin-only birth control in a 2016 systematic review published in Breast Cancer Research and Treatment.

However, the researchers did point out that the majority of the studies had small sample sizes, which limited their findings, and that more study was required.

When recommending a Mirena IUD, medical providers need to have a better understanding of the effects of synthetic progesterone on women.

Study of 2015 [ref]

A significant connection was found between breast cancer and Mirena in large research conducted in 2015 and published in the journal Acta Oncologica.

Study of 2014 [ref]

Women from Finland who used the Mirena IUD to manage heavy menstrual bleeding were the focus of a 2014 observational study published in Obstetrics & Gynaecology.

The research revealed that Mirena reduced the incidence of lung, ovarian, pancreatic, and endometrial cancer. The study did, however, show a greater prevalence of breast cancer than the researchers had anticipated.

Research that suggests no link

More than 15 years ago, Mirena became a drug. Its potential connection to breast cancer is still a matter of debate in the scientific community.

The journal Obstetrics & Gynaecology published one of the early investigations about a connection between Mirena and breast cancer in 2005.

According to the study’s findings, there is no link between using Mirena and an increased risk of developing breast cancer. [ref]

A 2011 study published in the journal Contraception found no link between Mirena use and an increased risk of breast cancer. [ref]

But does Mirena decrease the chances of Breast Cancer?

There is no evidence to support the claim that Mirena reduces the risk of breast cancer. This confusion is caused, in part, by the fact that it may reduce your risk of developing some other cancers.

Researchers came to the conclusion that IUDs that release levonorgestrel are linked to a higher incidence of breast cancer than was anticipated in the aforementioned 2014 study. [ref]

The incidence of these tumors was lower than anticipated, according to the same study:

• Lung cancer
• Endometrial cancer
• Ovarian cancer
• Pancreatic cancer

Mirena has additionally been linked to:

• Decreased risk of sexually transmitted infections (STIs)-related pelvic inflammatory disease (PID) (STIs)
• Endometriosis discomfort lessening menstrual pain

Can using other IUDs raise your risk of Breast Cancer or other types of cancer?

Currently available hormonal IUD brands include Kyleena, Skyla, and Liletta.

Similar to Mirena, all three labels have the same caution that you shouldn’t use them if you have, have ever had, or suspect having breast cancer.

They all admit that breast cancer has been reported in women who use hormonal IUDs. They all also agree that the evidence is inconclusive.

Every product has a slightly different hormone content. Levonorgestrel-releasing IUDs in general, rather than specific brand names, are discussed in the majority of studies looking into the connection to breast cancer.

You can still use an IUD if you’d prefer to completely avoid hormones. For example, the hormone-free copper T380A is sold under the trade name ParaGard.

It functions by inducing an immunological response that makes the environment unfavorable for sperm.