False positive result - caused by Mirena coil?

AFter 20 years of normal results, I got a high grade abnormal result last Wednesday, with an appointment for a colopscopy for the Friday. Given the speed of all this, I imagined the worst of course. On arrival for the test, the consultant said it was unusual to go from normal to such a high degree of severity in such a short space of time, but reassured me that at last the situation would be clear from the test. To our (joint) surprise, having done the colopscopy, he was unable to detect any signs of abnormal, pre-cancerous cells whatsoever. He's done a punch biopsy to be on the safe side, but suggested that there was nothing to be concerned about. The only reason he could give for this was that it's possible the nurse at my GP surgery failed to put on the form the fact that I have a Mirena coil. Apparently the hormones produced locally need to be taken into account when reporting on the results of the smear test.

Has anyone else come across this? Can anyone tell me what it is about the coil which can confuse the picture so dramatically? The Mirena is in widespread use, and I can't believe that this isn't something that happens routinely. Are there any other reasons for false positive results?

I'm feeling reassured (I think!), though I won't be completely ok until the results of the biopsy are back, which should be within 3 weeks. But if this is the case, I can't see how anyone with a Mirena coil can be sure their test results are ok! And what happens next time around, if I still have a coil.

Thanks for any thoughts on this.


Sorry I'm not much use to you but hopefully somebody who knows something about this will be along soon.

I also have a mirena coil & got a severe cell change smear result. My mirena coil was never mentioned though. Infact at colposcopy they only found out I had one actually during the examination! 

I can't remember exactly but I'm also sure the nurse who did my smear didn't ask if I had a coil or anything but I could of just forgotten. 

I meet my gynae-oncologist tomorrow and I do have a few questions about what could be caused by my coil and what isn't as I'm worried iv ignored some symptoms and passed it off as due to my coil so I shall ask for you and see what he has to say. 

hopefully you won't be waiting too long for you results.

Sorry I can't be of much more use.



Thank you Johanna - I really appreciate this! I hope your appointment goes well..

I did the usual googling last week (in a panic), as I wondered if the Mirena might in fact have caused the abnormal result i.e. actually caused cancerous / pre-cancerous cells. It seemed a bit of a coincidence that the first time this has happened has been in the 3 years since the coil was put in. Of course there were all sorts of people claiming a direct link, as well as lots of heath professionals saying that there is absolutely no link!

I put the fact that I have a Mirena coil on the pre-appointment questionnaire. When we were discussing stuff before the colposcopy he mentioned that the treatment (diathermy) might burn away the strings, meaning that when I came to have it removed (due in 1.5 years), this would have to be done in hospital. I had quite a few problems with it being put in, so even contemplated getting him to remove it before the colposcopy, but in the end of course, this wasn't necessary. It's been a godsend in terms of getting rid of bad period pain (the reason I had it in the first place), but if it's contributed in any way to this situation, or might cause problems with future tests, then I won't have another. In fact, I think that they say you can't have a coil put in if you've ever had an abnormal result.

Anyway, best of luck for tomorrow and thank you again in advance for asking those questions. This forum is proving to be a wonderful source of support and info.

Best wishes


Smear test 17.09.13; Severe high grade cell changes 01.10.13, colopscopy (no pre cancerous cells evident) and punch biopsy 04.10.13 

Iv found my mirena the best contraceptive or me aswel as controlling my awful periods. I now have none woohoo! But like you I am wondering if it has had any negative effects with regards to cell changes. I know mine will have to come out when I go for surgery & asked for them to remove it there and then but apparently they won't remove it right up until the day they do something as can't risk a pregnancy. Not that I'm having anytime fun times with all of their poking and prodding around up there! 




I have a mirena and also had my first abnormal smear recently (Always come back normal but suddenly showed as severe dyskaryosis on my last smear). I went for a colposcopy and they saw a small area of white after applying the solution. They did a lletz procedure and the results came back as no pre cancerous changes, just some mild changes related to HPV. They took  my case to the multi disciplinary team meeting due to the discrepancy between the results and have decided that they want to repeat the lletz!! I am not sure why they would repeat the lletz rather than do another semar, so I will ask the consultant when I go for my meeting.

They have never mentioned any link with my mirena, but I too am wondering how my cervix could change from normal to severly abnormal so suddenly, with no symptoms.


All the best


Hi Ladies

I have always had normal results up until my last smear (it was 18 months late as I found out I was pregnant literally days before my smear app). However, apart from taking the pill briefly in my teens and again briefly 10 years ago, I have never used anything other than condoms for contraception.....I decided to go for a copper coil fitting and was offered a smear at the same time so I kind of have it to thank for finding this out.....otherwise I may have blindly gone on for another year in blissfull ignorance of what was happening......

Anyway my point is I went from normal to high grade without the coil......my consultant has told me she is taking my copper one out when I have my lletz on Wed, she has offered to fit a mirena one a few weeks after once i have healed. I trust this lady, she has been fantastic and is apparently renowned in her field so I really doubt she would offer it to me if she thought there was any type of link or risk (in fact she persuaded me to have the mirena over the copper!!)

I can understand your doubts......but I would be very surprised if the mirena actually caused the cell changes. Only a thought I guess but I am living proof it does happen quickly without it.


Good luck :-) xx

Hi, I just wanted to add that I went from normal smears to CIN3 within 3 years and I'm dont have a coil so it can happen without that x

Thank you for these recent posts - really useful information. I've spoken with the doctor's surgery today to ask whether they can find out what was put on my form re my coil. I still don't really understand what the effect of having a coil might have been on the smear test. Either there are pre cancerous cells or not, surely?!! I guess that's what will be ruled in or out by the biopsy. 

Rachel x

Hi i was just wondering if you have any update on what your doctor said about your marina coil? Im also really confused as i had 2 abnormal tests 2 years ago when i had the coil, then 2 normal after my coil was removed, and now another abnormal and again i have the coil... this could be a huge coinsidence but it has left me abit puzzled...

I just found out that I have a first-time abnormal Pap smear and my HPV is negative. I will be having e biopsy tomorrow. I am 33 and have 2 boys aged 7 and 10.  I have Mirena for 7 years and a non-smoker, non-drinker, healthy eater  and no cancer history in my family. I think Mirena is the most likely culprit. 

I just found out that I have a first-time abnormal Pap smear and my HPV is negative. I will be having e biopsy tomorrow. I am 33 and have 2 boys aged 7 and 10.  I have Mirena for 7 years and a non-smoker, non-drinker, healthy eater  and no cancer history in my family. I think Mirena is the most likely culprit. 

I am 62. I had what ought to have been my last ever smear 3 months ago. I used to have the Mirena coil and had it removed when I went through the menopause.  I have had a high grade severe result from my last smear. At the colopscopy they found nothing at all to suggest I had anything wrong . They decided to repeat the smear. I had it yesterday. Nowe The wait. But the nurse seems to think I have something happening and won't admit at all that false positives occur. She even went so far as to say oh well you don't need your cervix anymore. I am so upset. I don't  really want to go back there and face her again. I have seen her twice now.