Mirena is a hormonal intrauterine device. Similarly to other hormonal IUDs, it releases levonorgestrel, a synthetic form of the naturally occurring hormone progesterone.
Progesterone often fuels breast cancer. Consequently, there has been a question about a link between breast cancer and hormonal IUDs, specifically Mirena.
Contents of this article:
- The Mirena IUD
- What does the research say about the link with increased breast cancer risk?
- Breast cancer and other IUDs
- The takeaway
Fast facts on breast cancer and Mirena
Mirena is used long-term and can prevent pregnancy for up to 5 years.
There have been varying reports about a link between the use of Mirena and breast cancer.
Other brands of hormonal IUDs on the market carry similar warnings as Mirena about breast cancer. All note the research but conclude there is no definitive evidence.
Mirena is only one long-term birth control option. If women have health concerns about using it, they should talk to their doctor and raise any worries before deciding.
The Mirena IUD
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| The Mirena IUD has been linked to an increased risk of breast cancer, but how accurate are the findings? |
The Mirena IUD works by thickening the cervix which stops sperm from reaching the eggs released from the ovaries. It also thins the uterine walls, which means that, for some women, ovulation is suppressed.
What does the research say about the link with increased breast cancer risk?
The most recent information-labeling leaflet acknowledges a potential risk for women. It states that women:
"who currently have or have had breast cancer, or suspect breast cancer, should not use hormonal contraception because some breast cancers are hormone-sensitive."
The makers of Mirena further note that the research studies on the increased risk are not definite.
Research saying there is no link
Mirena has been on the market for more than 15 years, and more research is still needed to provide a conclusive answer about its link to breast cancer.
One of the earlier studies about a link between Mirena and breast cancer dates back to 2005 and was published in the journal Obstetrics & Gynecology. The results of that study did not suggest any connection between the use of Mirena and breast cancer risk.
Another study from 2011 reported in the journal Contraception also found no increased risk of breast cancer in women using Mirena.
Research saying there is a link
A 2014 observational study reported in Obstetrics & Gynecology looked at women ages 30-49 years from Finland, using Mirena to control heavy menstrual bleeding. What they found was that Mirena decreased the risk of endometrial, ovarian, pancreatic, and lung cancers. However, it was associated with higher incidences of breast cancer.
A large study from 2015, reported in the journal Acta Oncologica, also found a connection between the increased risk of breast cancer and Mirena use.
A 2016 report in Breast Cancer Research and Treatment agreed with previous findings that progestin-only birth control was associated with higher incidences of breast cancer. But the researchers noted that most of the studies were limited by sample sizes.
More research is needed to confirm these findings and to understand better how synthetic progesterone affects women and how doctors can use this information when prescribing contraceptives, containing synthetic progesterone.
A newer report published earlier in 2017 in Post Reproductive Health reports that any connection between breast cancer and hormonal contraception is relatively small and the benefits of contraceptives outweigh the risks.
Breast cancer and other IUDs
There does not appear to be any research studies indicating any increased risk of breast cancer associated with the use of the ParaGard IUD. If women want to avoid hormonal birth control altogether, ParaGard might be a better option for them.
Several studies, including a recent report in the journal, Evolution, Medicine, and Public Healthhave reported an increase in the incidence of breast cancer in women, using hormonal oral birth control.
The 2017 study reviewed data from 12 separate studies for a hormonal birth control-containing serum estradiol and progesterone in women ages 19-40 years.
The researchers found that breast cancer risk was increased with hormonal exposure. But they noted their results only pertained to the types of hormonal birth control they investigated, and they were unaware of any increased risks associated with other hormonal birth control methods.
The level of hormones depends on the product, so it is important for women to discuss their concerns with a doctor to determine whether the risks outweigh the benefits.
The takeaway
Birth control is a personal choice. While some methods might be more reliable than others, it is important that birth control is always used correctly. Furthermore, it is most important for women to choose something that is effective and ideal for their lives.
When making a decision, the best course of action is for a woman to talk to her doctor about any concerns she may have to determine what the best option is for her.
