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In praise of Mirenas

I think Mirenas are awesome. There – I’ve said it and I’m not taking it back. I have, on average, been putting in 2 to 3 Mirenas a week for at least the last 7 years. They have revolutionised women's health care in the last 15 to 20 years. I think most gynaecologists and general practitioners would agree with me.

When I was a young lad (actually I was 36) flush with the excitement of commencing training in O&G the choice of options for treating women with heavy periods was limited. Several medications including the pill would be trialled and if these failed you would be looking down the barrel of having a hysterectomy. Uteruses were removed at a rate of knots. I remember in my first year of training doing three vaginal hysterectomies on one afternoon list. That sort of operative experience is just not available for most trainees currently because Mirena’s have made such a dent in those women needing hysterectomies.

Yes – there are other less invasive operative options available. An endometrial ablation essentially “cooks” the inside of the lining of the uterus. Hmmm – sounds inviting doesn’t it. It does work well though with patient satisfaction rates of between 80-90% and up to 30-40% of women having no bleeding after the procedure. The majority of those that are dissatisfied go on to have a hysterectomy.

When I was a medical student an ablation procedure was rather laborious and took a reasonably long time to perform. The modern ablation device is all pre-packaged, computer-chip driven and quick. Most procedures take less than 3 minutes to perform. The recovery is quick – back to work within a few days for most patients. There is a pinkish, watery discharge for up to 2 weeks later and cramping for a few days. Not everyone will be suitable for an ablation – for example, if you’ve got fibroids causing your periods – an ablation will likely do very little. Some women will also be unable to have an ablation because of issues related to previous caesarean sections.

Mirenas sit between the non-invasive option of medications and the very invasive ablation or hysterectomy. I insert 2 to 3 Mirenas a week and most of those are inserted in my rooms. With the assistance of a skilled assistant (usually Sherry – for those of you who know her) I have a success rate of being able to insert a Mirena in the rooms of more than 90%. There are a small number of women who will need to have a general anaesthetic to have their Mirena inserted.

Mirenas are about 3 cm long and about 3 mm wide when inserted. When the arms are deployed within the uterus they extend to a “wing span” of about 3cm. The Mirena sits within the cavity of the uterus. The stalk of the Mirena has a reservoir of progesterone that is released over the course of 5 years and gives you a contraceptive equivalent of having your “tubes tied” BUT it is completely reversible. When your Mirena is removed you will within a very short period of time go back to “normal” for you. If you were very fertile when you had your Mirena inserted 5 years ago – you will likely be very fertile again, except of course for the fact that you are now 5 years older and slightly less fertile because of that. The progesterone that is released also thins the lining of the uterus and thereby gives you lighter, and often, lighter periods. The Mirena was initially invented for reducing the heaviness of periods but is also now used as a contraceptive with the added bonus of lighter, and sometimes absent periods.

At the time of insertion you will have some cramping pain and that usually lasts for anywhere between a couple of hours and a couple of days. Uncommonly it will last longer and a very small number of (usually younger) women will end up having their Mirena removed because of ongoing cramping.

Your bleeding will become a little erratic with lots of breakthrough bleeding (usually light) to start with. Your periods will be longer but lighter to start with but then get lighter and shorter as time goes on. I usually cajole women to persist with the Mirena for at least 4 and usually 6 months as I know that the majority of them will end up being happy despite being driven crazy by it in the first place. By 6 months 80-90% of women are very happy. By 12 months up to a third of women will have NO periods.

So it’s all sounding a bit too good isn’t it. You’ve heard the horror stories – they abound on internet forums. And you know what – most of them are true. If you look at the list of potential side effects of having a Mirena it’s as long as your arm. Here’s a man holding a list of the side effects of a Mirena.

Here’s the same man holding a list of potential side effects of the oral contraceptive pill. Something like Levlen, for example. Somewhere in that list is heart attack, stroke, pulmonary embolism and deep vein thrombosis.

Here’s that same dude again. Damn it, this time he’s got a list of the side effects of Aspirin – are you getting the picture?

So what are the other side effects that I see with Mirenas that are not related to irregular bleeding. Breast tenderness, headaches, skin changes (oily and sometimes acne), increased risk of ovarian cysts (benign), mood changes, anxiety, loss of libido. My goodness, the list goes on and on and on – why on earth would anyone want to have one of things inserted into their body.

Why? – because a Mirena is the most effective long-acting reversible form of contraception.

Why? – for a lot of women who have heavy and/or painful periods, a Mirena is a godsend.

Why? – because if you have endometriosis, a Mirena can keep your endo at bay.

Why? – because some women can’t tolerate other form of contraceptives or don’t want to have surgery for their specific gynaecological condition.

Most of the time Mirena side effects are significant to start with but then get better over the passage of time. Do they get better for everyone – NO. But if they don’t then you remove the Mirena – usually a relatively easy thing to do – and look at using something else.

The patients that get the side effects are not always predictable. About 5 years ago I had two patients with severe depression who had extremely heavy periods. Their choice was to either put up with their periods, have a Mirena inserted or have a hysterectomy. Given the fact that Mirenas can cause a depression of mood and they had both been admitted to hospital with depression multiple times, had attempted suicide multiple times and had previous electroconvulsive therapy for their depression I was a little reluctant to use a Mirena. They were reluctant to have surgery and they had tried all other treatments and wanted to try a Mirena. So….. I inserted a Mirena and crossed my fingers. BOTH patients have never looked back and they love their Mirenas.

Sometimes women are happy to put up with side effects if it means that the benefits outweigh the side effects. A young woman in her 20’s had a Mirena inserted for her heavy, VERY painful periods. She came back for review a couple of months after insertion and told me that her periods were much better but since having the Mirena inserted she was experiencing significant vaginal dryness. I had never heard of this side effect before but sure enough down in the small print, it was listed. I reluctantly told her that the only way we could eliminate the Mirena as a possible cause of the dryness was to remove the Mirena. “No way!” she exclaimed, “ I can put up with a bit of vaginal dryness. My periods are so much better there’s no way that I’m having my Mirena taken out.”

Where do you have a Mirena inserted? – approximately 90% are inserted at our rooms without the need for a local anaesthetic injection although we do use “happy gas” for some patients

When should you have a Mirena inserted? – it’s best to insert it at the tail end of your period or within a few days of your period finishing

Who can have a Mirena inserted? – not everyone will be suitable to have a Mirena inserted but most women with an anatomically normal uterus (i.e. no fibroids or congenital abnormalities of the uterus) will be suitable. Women who have not been pregnant can sometimes be a little more difficult to insert a Mirena into as the cervix can be narrower but it is still usually possible to carry out the procedure in the rooms.

Is there an age limit? – generally NO. I have inserted Mirenas for teenagers through to women in their 50’s. In older women it is important to rule out a possible sinister cause for their heavy and/or irregular bleeding and in this age group it is more likely that their Mirena insertion is done as a day surgery procedure where the uterus is assessed fully at the same time as the Mirena insertion.

So – in summary…….

Mirenas can be good – 80-90% of women love them

Mirenas can be bad – 10-20% have them out because of various side effects, the commonest BY FAR being irregular bleeding.

I suspect that a lot of women who end up having their Mirena removed (particularly early) have not been properly counselled regarding its’ possible side effects prior to insertion. Lets face it - if you had something put in your uterus to reduce your heavy periods and you ended up with break through bleeding and sore breasts and you weren’t aware that these were going to be possible side effects, you’d be at the very least a little peeved and wanting to have that damn thing taken out.

One last note – the box that the Mirena comes in is BIG. The actual Mirena is small but the box is big. If you decide to have one put in take a large shopping bag when you go to the chemist to pick it up.

The best person to talk about whether a Mirena might be suitable for your gynaecological issue is your GP and your gynaecologist. And NO I don't have shares in the company that makes Mirenas.

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