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Contraception, IUD

Mirena IUD effective for seven years – new study

LoveMyLARC-PNG-Vertical-300-White_0The Mirena intrauterine system (IUS), the IUD with the hormone levonorgestrel, is a highly effective method of contraception currently approved for five years. Some data suggests that it probably good for six years, but a new study tells us with a good degree of confidence that the Mirena is safe and effective for seven years. Yes, seven years.

The study was funded by UNDP/ UNFPA/WHO/World Bank Special Programme of Research and published in the journal Contraception. The investigators compared the Mirena IUS head to head against the copper IUD. Almost 4,000 women participated in the study and they were randomized, meaning neither the women nor their physicians were allowed to select the IUD (this helps to remove some kinds of bias). The women were followed for pregnancies and reasons for removal.

By the end of year seven only 0.53% of women with the Mirena IUS had became pregnant versus 2.45% for the copper IUD. There were seven pregnancies among 1,884 women. While the copper IUD is an excellent form of birth control the Mirena was even more effective. In fact, it is far better than any other method of birth control. Based on this data a pregnancy with a Mirena is almost a reportable event, that’s how rare it is. 

Along the way many women had their IUDs removed, typically because they desired pregnancy or had side effects. There were 717 Mirena users who completed six years of follow-up and 398 women who completed seven years with no pregnancies in year 6 or 7. With the copper IUD there were four pregnancies in total in years six and seven. There were slightly more copper IUD users in year six and seven as early removal was more common among Mirena IUD users and this was driven largely by women at the Chinese centers who don’t find amenorrhea (lack of periods), a side effect of the Mirena, to be acceptable. An interesting cultural difference as amenorrhea is more often than not valued by contraceptive users in the United States. 

What also stands out from the study is the absence of ectopic pregnancies in the Mirena arm. Let me state that again because it’s really important, not one women out of the almost 2,000 who had a Mirena had an ectopic pregnancy. Three of the 33 pregnancies with the Copper were ectopic. It’s possible that there were just too few pregnancies with the Mirena to detect ectopic pregnancies, but it’s also possible that either levonorgestrel changes cervical mucus in such a way that sperm has no chance or that the local hormonal effects are as good in the fallopian tube as they are in the endometrium. It’s not really possible to say as he exact method of pregnancy prevention isn’t known. We know it’s not ovulation suppression because by year four 75% of cycles with the Mirena are ovulatory

If a Mirena IUD is $700 for insertion (that’s just an average) in addition to the convenience of extending the lifespan for two more years the cost per year will be $100 instead of $140.

Could he Mirena be good for eight years? The manufacturer was worried that there wouldn’t be enough levonorgestrel for an adequate endometrial effect (one proposed mechanism of action), so a plan to extend the study to eight years was scrapped. Given the lack of pregnancies in year 6 and 7 with the Mirena and a cumulative pregnancy rate of 0.53% one has to wonder if the Mirena would perform better than the copper and its 2.45% failure rate at the end of year eight. 

Bayer has little incentive to prove the Mirena lasts longer. They make money by selling new product. It’s unlikely they will submit to the FDA for a change in product labeling or invest in a study to test efficacy after eight years. Hopefully the WHO will invest in this because the longer a woman can use a highly effective and reversible method of contraception the better. 

So good news! The Mirena is not only the most effective form of birth control and has a stunningly low ectopic pregnancy rate, but it’s also good for seven years!

Discussion

22 thoughts on “Mirena IUD effective for seven years – new study

  1. Prevents endometrial cancer.

    Posted by Judith | September 10, 2016, 1:16 pm
  2. Excellent information. Thank you for posting. It would be wonderful if more women around the world were able to avail themselves of the Mirena.8

    Posted by Patty Smith | September 10, 2016, 2:09 pm
  3. Back in 2013, my ob/gyn preceptor was recommending his patients use their Mirenas up to 7 years. I’m not sure what data was available then, but he said it was common practice in Europe. I’d love to keep my Mirena longer (insertion was the only not-fun part of Mirena for me), so I’m glad there is this data to back up the 7 year recommendation.

    My favorite question I get asked about amenorrhea is, “Since you don’t have a period, how do you know you’re not pregnant?” Uhh… because I have a Mirena. I understand why a general public person would ask this question, but it’s a bit concerning when a healthcare provider asks it.

    Posted by easwanson2005 | September 10, 2016, 6:15 pm
  4. I would love to learn more about amenorrhea. I have asked several OB/GYNs if it is safe, and they all say yes, but without an explanation. I have been wanting to try a new birth control that allows amenorrhea, but am afraid it’s unhealthy or will lead to side effects later in life. I think this would make a great blog post, and would love to hear your feedback.

    P.S. – I am subscribed to your blog and always love reading your posts when they hit my inbox!

    Posted by Tori | September 12, 2016, 1:31 pm
    • Your mileage may vary. My periods were as regular as ever, just lighter.

      Posted by Xenobio | January 13, 2017, 3:46 pm
    • With hormonal contraception like Mirena, the lining of the uterus becomes so thin that there is nothing to slough off, hence, no period. This has no long term effects so once the device is removed, the lining begins to thicken again, with a return to normal menstrual cycles. There is nothing unhealthy about this, and in fact, for many women with heavy periods, this cures their iron deficiency anemia.

      Posted by Elizabeth | May 17, 2017, 6:08 am
  5. What do you think about keeping Mirena 8 years rather than 7? Seems like from your post that it’s entirely possible it’s effective into year 8 as well, they just abandoned the study.

    Posted by Michelle | November 9, 2016, 5:43 pm
    • I’m thinking it is worth trying.
      And then, armed against the future, start working with young people so that in two years and four years, you don’t have to worry about that 8th year. Midterms matter. If people under 30 actually vote, they’ll all be thrown out.

      Posted by Lily | November 10, 2016, 10:28 am
  6. I just had my mirena removed today after 8 years and ten months. I had complete amenorrhea for the entire time (minus the first 6 months when it was gradually decreasing).

    Posted by Renee | December 14, 2016, 8:48 pm
  7. GOSH DANGIT I could have hung on to mine for another 2 years. My husband was freaking out and refused to have sex from the official 5 year expiry date, until I got a new IUD (despite me yelling “You’re a biomedical engineer, you know expiry dates don’t work like that”). I got it replaced with the copper one for reasons of being a cheapskate (living in South Africa, on student insurance that only covers the copper T) and am regretting it because of the heavier periods.

    Posted by Xenobio | January 13, 2017, 3:45 pm
  8. I have had my Mirena for 12 years *married, monogamous, annual paps, mammograms & minimal risk factors for reproductive cancers or any life-threatening illnesses. My point- I felt I was extremely LOW-RISK for any infections, STDs or physical complications arising from my decision to go against recommendation of 5 year removal plan.*
    I am just recently starting to ovulate and I have had one menstrual cycle that lasted a full three days that required no more than a panty liner to manage. Prior to Mirena I needed RX Ponstel and Tylenol #3 for 8 days of HELL. Based on my slow return to cycling compared to my barely manageable previous cycles(age 9-30) I’m confident the amount of hormones in the IUD and their effectiveness FOR ME have remained steady for 12 years.

    Posted by Jody | March 25, 2017, 7:46 am
  9. Can I get a reference to this new study?

    Posted by ET | March 29, 2017, 3:51 pm
  10. I’m sure doctors would be horrified but I kept my Mirena in for 13 years. I wasn’t having periods and I didn’t want anything to change that. I did not remove it untill my periods resumed. I never had any complications during that time either.

    Posted by Colleen | May 7, 2017, 12:42 am
  11. This is all very helpful. I’ve had my Mirena for 6.5 years. I saw an ob/gyn at 5 years and was told not to rush replacement, it’s good for longer. Does anyone have links to information on maximum time before replacement besides for birth control?
    I am not currently sexually active, so the key benefit of my Mirena is no periods. Can I leave it until periods resume, or is there any other reson to replace?

    Posted by Lesley | July 16, 2017, 8:54 am
  12. I had my son in January 2002. Mirena march.m 2005. 15 years later I still have it in. With no problems

    Posted by Maryann rhoades | August 15, 2017, 10:26 pm
  13. Thanks for posting Dr Gunter. I just looked at my expiry date on the booklet my gynecologist gave me and I’m more nearly 4 months past the five year mark so started to panic! Off to have a chat with my gynecologist about whether I should get it replaced – will refer to this study.

    Posted by Julia | September 24, 2017, 6:06 pm
  14. I had the mirena in for 10 ½ years and it worked perfectly. I never had a period…the entire time. Never got pregnant. But ladies, let me warn you. As soon as you have the mirena removed, you will be fertile myrtle. My suggestion. One comes out and another goes in. Unless you are trying to conceive and then you are good to go. By the way this is 100% of personal experience.

    Posted by pantrygoods | October 10, 2017, 5:14 pm
  15. I have had my ParaGuard in for 10 years, I have had 2 kids, I just turned 50 & still have my period. I have never any problems with my IUD, but do I really have to get it out & have another put in to wait until I reach menopause? My periods did become heavier for a few months, so I was worried about IUD not working anymore, but after reading some info, I feel like leaving it in until my periods are gone.

    Posted by shari crane duscenne | November 8, 2017, 2:27 pm

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  1. Pingback: IUDs and Implants: It’s Not Too Late for LARCs | Planned Parenthood Advocates of Arizona - October 10, 2017

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