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Contraception

How does the Skyla IUD compare to the Mirena?

skylaThere is a new IUD on the market called Skyla. It is made by Bayer, the same manufacturers who brought us the Mirena. Like the Mirena it contains the hormone levonorgestrel, although there are a few differences. The main difference the company is touting is the smaller size. Clearly, they manufacturers are targeting nulliparous women with the promise that a smaller size might mean an easier insertion.

I have summed up Skyla and Mirena in this chart so you can compare them side by side:

Skyla Mirena
Number of years 3 5
Size 30X28 mm 32 X 32 mm
Amount of levonorgestrel in drug reservoir 13.5 mg 19.5 mg
Amount of levonorgestrel released/day at start 14 mcg/day 20 mcg/day
Amount of levonorgestrel released/day at the end 5 mcg/day 10 mcg/day
Cost in $US $650.32 $703.05
Pregnancy rate by end of 3 years 0.33/100 woman years 0.31/100 woman years
Expulsion rate at 3 years 4.56% 3.58%
Discontinuation due to abnormal bleeding 4.7% 4.9%

What about pain with insertion? A randomized study was published this month (Obstet Gynecol Nelson et al November, 2013) ) where the women were blinded to which IUD they received (obviously the investigators knew which IUD they were inserted) gives us some more data. Over 2,800 women received a Skyla or Mirena (just over 1,400 in each group) and 96% of insertions (lumping both Skyla and Mirena together) were successful the first time and 65% of women reported their pain as none or mild. This is very reassuring considering 39% of women in this study had never been pregnant. Interestingly, the study did not report pain or ease of insertion specifically for Skyla versus the Mirena, bur rather lumped them together. It seems incredible to me given the data presented in the study that they didn’t have the breakdown by IUD. The study was funded by Bayer so it makes me wonder if there was actually no difference in pain or failed insertion attempts between the two and so they elected not to disclose that information. Sigh.

Abnormal bleeding patterns, breast tenderness, acne, headache, weight gain, pregnancy rates, and serious adverse events were the same between the two groups so there does not seem to be a side effect, efficacy, or safety advantage for Skyla over Mirena. The only statistically significant difference that came out in this study was a slightly higher incidence of ovarian cysts with Mirena over Skyla (13.8% versus 7.7% by 3 years).

The disadvantage to Skyla besides cost? If you are planning on needing contraception for a long time a shorter duration of use increases your risk, as the biggest risk with an IUD is with insertion the longer acting the IUD the safer.

The take away message is that Skyla is a fine contraception, but unless more data is released it seems like there is no real advantage over Mirena for anyone except perhaps for women with a history of recurrent ovarian cysts and of course Bayer as Skyla is more expensive per year of use.

It is no coincidence that Skyla comes at a time when the patent has expired (or is about to expire) on Mirena.

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Discussion

10 thoughts on “How does the Skyla IUD compare to the Mirena?

  1. “slightly higher incidence of ovarian cysts with Mirena over Skyla (13.8% versus 7.7% by 3 years).”

    I don’t understand this part. That seems like a big increase – doubled incidence??
    Or does it mean the increase on likelihood, like the likelihood was small and that small number increased by 14%. Sorry for the weird questions. Thinking of switching to an iud at my next appointment so I want to know what I’m getting into. Thanks.

    Posted by Vicky | November 20, 2013, 8:23 am
    • While a doubling in the incidence of cysts seems big, it may or may not be and unfortunately the study isn’t powered or really even designed to look at ovarian cysts. For example, if the incidence of ovarian cysts in women who got a copper IUD were 10% that might make the 13.8% meaningless. Also, as the removal rate for complications were essentially identical for the Skyla and the Mirena, so even if there were a true increase in cysts they did not seem to have any health impact.

      Other studies report the incidence of ovarian cysts at about 10% with Mirena, which may or may not be statistically difference from the 7.7% for Skyla. So, without a study designed to specifically look at cysts I think it’s really hard to draw a firm conclusion from this study. For me, the most important thing is the removal rates were the same so even if the true incidence of cysts is higher (which this study wasn’t really designed to tell us), it doesn’t seem to have a clinically significant outcome.

      Hope that helps! And good question, thanks for asking!

      Jen

      Posted by Dr. Jen Gunter | November 20, 2013, 1:37 pm
  2. The Skyla seems like a strange option. I am on my third Mirena and if they had a ten-year version I would switch to that since insertion really is the worst part. For the next one I’m going to see if I can find out which doctor in the practice has the most experience and see that person, but that will be in 2017.

    I know that copper does last ten years but the benefits of not getting my period are huge for me: no dogs tearing through the bathroom trash, no purchasing feminine products, no cramping, no eating salt from the shaker, no ruined clothes, no surprises at work, no turning down sex ; )

    Whenever I hear about men getting vasectomies for birth control I’m (quietly) horrified that a couple considered that their best choice. It seems a lot more painful, a lot more permanent, and someone still gets their period.

    Posted by Tribi | November 20, 2013, 8:25 am
    • I will happily take my husband down for his and he will happily get it, 12 yrs of me being on hormonal birth control wrecked havoc on our relationship and would have still if I hadn’t got a copper IUD and have resumed my normal levels of crazy. You name it I tried it and it all made me crazy or have abyssal side effects, sometimes a vasectomy is BEST gift a husband can give his wife because my body has been the battleground for our fertility and if with a simple outpatient snip he can show his appreciation of my taking control, the risk and side effects of our war against our fertility for 12 yrs i won’t stop him.

      Posted by Oubli | November 21, 2013, 9:47 am
  3. I am really happy with my Skyla. I am really hormone sensitive, the Mirena gave me awful awful headaches. So far three months into Skyla and no headaches! Still getting my period, though.

    Posted by Nikki | November 20, 2013, 7:31 pm
    • I also have the Skyla IUD and had it inserted in December 2013. I am starting to freak out—I had a period the month I got it, and then one last month, and now the 3rd month (Feb)–I don’t have it yet! I know it’s only a few days late, but just wanted to see if you had any irregular cycles or months where you had or didn’t have one. Thanks, Christina

      Posted by christina | February 22, 2014, 10:20 pm
  4. I’m curious if the Skyla would be better for breast feeding women? Could that be a benefit? I chose Mirena after my Kiddo was born because of breast feeding, because I was told that the levonorgestrel alone was better than the combo pill (yes, I know that the mini pill is an option. But, seriously, with a newborn how is a pill that I have to remember to take at the exact same time every day a good option? I know a copper IUD might be better, but I have awful periods when not on BC.)

    Posted by Amanda | November 20, 2013, 8:28 pm
  5. Dr. Jen, from one physician to another, thank you for the analysis!! When do you have time to do this reseach and writing??!! I do not even practice OB any longer..and I do not think I could find the time..
    I think the difference in the size seems minimal, and probably not significant in terms of successful insertion ( as you pointed out).
    I hope the patent results in a lower cost, but of course this will not translate to any increase
    in the insertion fees to providers, which I think is too low for the risk we take and the preparation in terms of counseling…

    Posted by Janis L. Enzenbacher | November 29, 2013, 2:30 pm
  6. Is Skyla safer for breast (against developing breast cancer) as it contains lower dosage of Levonorgestrel compared with Mirena? Thanks, kate.

    Posted by Kate | March 19, 2014, 6:32 am

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  1. Pingback: Check Out! New Mirena lawsuit information | Consumer Advocacy - December 12, 2013

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