Contraceptive counselling often features in OSCEs and therefore it’s important to be familiar with the various types of contraception available. This article focuses on counselling patients regarding the Mirena intrauterine system (also referred to as the IUS, Mirena coil or hormonal coil), including the common questions patients ask, the answers you’ll be expected to articulate and how best to structure the consultation overall. There are several types of IUS available, each with varying levels of hormone and lifespan, but for the purposes of this guide, we are focusing on the Mirena IUS.
Opening the consultation
- Introduce yourself
- Check the patient’s details (name/date of birth)
- Check the patient’s understanding of the types of contraception available
- Explore the reasons why the patient wants the Mirena IUS
Patient’s ideas, concerns and expectations
It is important to explore the patient’s ideas, concerns and expectations early in the consultation, as you may need to correct any misconceptions about the Mirena IUS and address any of the patient’s concerns.
Some patients may be worried about the insertion procedure, others may wonder about hormonal side effects (e.g. weight gain) and therefore having a good understanding of the facts is essential to appropriately address the patient’s concerns.
When exploring concerns, it is important to do so in a sensitive and honest manner.
It’s also important to clarify the patient’s expectations of the Mirena IUS, because if these are unrealistic, other forms of contraception may be better able to meet their needs.
What is the Mirena IUS?
Ensuring to use patient-friendly language, explain that the Mirena IUS, is a small plastic device that sits inside the uterus and releases a hormone called progestogen. There are two threads which pass through the cervix and lie in the vagina.
- “The Mirena coil is a small plastic T-shaped device that will sit inside your womb.”
- “There are two threads attached to the device which pass through the neck of the womb, these are important in allowing you to check that the device is still in place.”
How does the Mirena IUS work?
Explain to the patient that the Mirena IUS contains a small amount of progesterone which causing thickening of mucus in the neck of the womb. ¹ This creates a plug which stops sperm from getting through the neck of the womb to fertilize the egg.
Also, explain to the patient that the hormones can make the lining of the womb much thinner. This means that even if an egg was fertilized, the likelihood of it implanting into the womb is very small.
- “The Mirena coil releases a small amount of hormone into your womb. This causes the mucus around the neck of the womb to thicken, making it difficult for sperm to pass through and fertilise an egg.”
- “In the unlikely event that sperm does get through this thickened mucus, the hormone released by the Mirena coil also makes the lining of the womb really thin, so even if an egg was fertilised, it would be very unlikely to implant.”
- “In some people, it stops the ovaries releasing an egg (ovulation), but most people who use an IUS continue to ovulate.”
How effective is the Mirena IUS?
Often patients want to know how effective contraception is, as this can help guide their decision on what contraception to choose. As a result, it’s useful to know some basic statistics on efficacy. However, if you’re unsure, signpost the patient to a reliable source and don’t guess!
- “The Mirena coil is over 99% effective.”
- “Less than one Mirena user in 100 will get pregnant in one year.”
- “If 100 sexually active women don’t use any contraception, 80–90 will get pregnant in a year.”
Pros and Cons of the Mirena IUS
Always give patients as much information as possible so that they can make an informed decision. It is useful to do this by discussing the pros and cons of choosing the Mirena IUS.
“If it is okay with you, I’d like to tell you about the benefits and disadvantages of the Mirena coil, then hopefully you will have enough information to make a decision.”
Advantages of the Mirena IUS
“The Mirena coil is 99% effective and will last for 5 years. One of the reasons it is so effective is because you don’t need to remember to use it.”
Problems associated with periods improve
“The Mirena coil can make your periods much lighter, shorter and sometimes less painful. After 1 year, most women find that they only have a light spot once a month and 1 in 5 women do not bleed at all.” ¹
Can be reversed easily
“As soon as the Mirena coil is removed, fertility resumes as normal.”
“Unlike the combined pill or mini pill, the hormone released from the Mirena coil is mainly contained within the womb, so less going around your body in your blood. This means that the likelihood of hormonal side effects is less.”
“The Mirena coil is safe to use if you choose to breastfeed your baby.”
“Unlike some other forms of contraception, there is no evidence that the Mirena coil will increase your risk of cancer of the cervix, womb or ovaries.”
Not affected by other medications
“Because the Mirena coil acts locally, it does not depend on your ability to absorb it through your digestive system, like oral contraceptives. As a result, it is not affected by taking other medications.”
Disadvantages of the Mirena IUS
“Especially in the first 3-6 months, irregular bleeding or spotting is common. Periods usually become much lighter, however, they may still be irregular. Although this often settles down, it can be quite bothersome for some people. ”
“Some people may get side effects like acne, headaches or breast tenderness. These usually get better after the first few months.”
No protection from STIs
“Unfortunately, the coil does not protect you from sexually transmitted infections (STIs). Barrier contraception (e.g. condoms) is the only form of contraception to provide protection from STIs.”
Some risks of the Mirena IUS
- “There’s a small chance of you getting an infection during the first few weeks after an IUS is put in. You may be advised to have a check for sexually transmitted infections before an IUS is fitted or at the time it’s fitted”
- “If you were to develop an infection, you would likely notice some abdominal pain, vaginal bleeding, fever and abnormal discharge. This can often be treated with a course of antibiotics, however, in some cases, the IUS may need to be removed.”
- “After the first few weeks, your risk of infection returns to the same as someone without a Mirena coil.”
Expulsion of the IUS
- “Sometimes the coil can come out without you realising. If this does happen, we can give you advice on what to do next, and we will teach you how to check that the coil is still in place.”
- The most likely time for this to happen is soon after insertion and/or during a period, so we typically advise to check your coil is in place after each period, once a month.”
- “If you were concerned the coil might be been expelled, you would need to use an alternative method of contraception and seek review from your local GP or sexual health service.”
Damage to the womb
- “When you get the coil fitted there is a very small risk that the device might perforate your uterus or cervix.”
- “This is rare, occurring in around 2 in a 1000 Mirena coil insertions.”
- “It is most likely occur in women who have recently given birth or are breastfeeding.”
- “If this was to happen, you may have to undergo surgery to remove the device and repair the perforation.”
- “The Mirena coil is a highly effective contraceptive method, however if you do fall pregnant whilst using the Mirena coil, there is a high risk that the pregnancy may have implanted outside of the womb, in the fallopian tubes, which is known as an ectopic pregnancy.”
- “Ectopic pregnancy is potentially life-threatening and therefore if you have a positive pregnancy test whilst using the Mirena coil you need to see a doctor urgently, who will assess you and arrange a scan to check the location of the pregnancy.”
- “Your overall chance of having an ectopic pregnancy is still less than someone not using contraception.”
How is the Mirena IUS fitted?
It is useful to explain the process in a before, during and after structure. This will also help you remember the key points for each step.
- “Before the Mirena coil is fitted, we need to be confident you are not pregnant and therefore we would advise avoiding any unprotected sexual intercourse in the 2 weeks prior to insertion. A urine pregnancy test may be performed, to check you are not pregnant.”
- “The coil can be fitted at any time in your menstrual cycle, but it is better to have it fitted towards the end of your period, as insertion is often easier and you are unlikely to be pregnant.”
- “Ideally, you should take some paracetamol and ibuprofen around 1 hour before the procedure, as this will help make things more comfortable.”
- “A doctor or nurse will perform a bimanual vaginal examination, which involves placing two fingers into your vagina and one hand on your tummy to assess the position of the womb, which is important to know before inserting the device.”
- “The nurse or doctor will insert a speculum into the vagina, to allow the neck of the womb to be visualised.”
- “You may then choose to have some local anaesthetic injected into the neck of the womb, which can make the insertion process less uncomfortable.”
- “A surgical instrument is then attached to control the position of the neck of the womb. There can sometimes be some discomfort when this is attached.”
- “A small plastic tube is then passed through the neck of the womb, to check the size of the womb cavity, before being removed.”
- “The Mirena coil is then inserted using another thin plastic tube. Once the Mirena is inside of the womb, the T-shaped arms open out to secure the device. As the Mirena device is inserted through the neck of the womb, you may experience period-like cramping”
- “The insertion device is then removed.”
- “Finally, the two threads of the Mirena will be trimmed, so that they sit high up in the vagina.”
- “Overall the procedure should take around 5 minutes in total.”
- “After the procedure, you may have painful cramps and light vaginal bleeding for the next few hours, so we advise resting and using painkillers as needed.”
- “As long as you are able to feel the threads yourself in a months time, you do not need to come back for a review. If however, you are unable to feel them, you will need to book an appointment.”
- “The coil lasts for 5 years when used for contraception, so you would need to have the device replaced or use an alternative method of contraception once the expiry date is reached.”
Removing the device
- “The Mirena coil can be removed at any time via a simple procedure. Should you want to have the device removed, you need to make an appointment with your GP or local sexual health clinic.”
- “It is important to know that if you are planning to have the Mirena coil removed, you will need to abstain from sex or use an alternative method of contraception for the week prior to removal. This is because sperm can survive for several days in the vagina and womb and therefore there is a theoretical risk of pregnancy after removal of the device.”
How do I check the threads?
“A Mirena coil has two threads attached to the end that hang a little way down from your womb into the top of your vagina.”
The patient should be shown how to check the Mirena IUS threads using a test device, to allow them to get an idea what the threads should feel like.
“We would advise checking you can feel your threads a few times in the first month and that at regular intervals each month (e.g. after your period). If you were concerned the coil might be been expelled (e.g. you can’t feel the threads), you would need to use an alternative method of contraception and seek review from your local GP or sexual health service.”
Closing the Consultation
- Ask the patient if they have any further questions or concerns that haven’t been addressed.
- Throughout the consultation you should check the patient’s understanding at regular intervals, using phrases such as “Can you just repeat back to me what we’ve just discussed regarding…”.
- It may also be useful to quickly summarise what you have spoken about and direct the patient to any websites or leaflets with further information.
- Make it clear that it is entirely the patient’s choice on what contraception she would like, and offer her time to think about her decision.
- Encourage the patient to use condoms if is she is currently not using any contraception and is sexually active.
- Thank the patient for her time.
1. Harding, D. (2017). Intrauterine System. [online] Patient UK. Available here [Accessed 2nd Oct. 2018].
2. The Family Planning Association. Published May 2018. IUS (intrauterine system) Patient Information Leaflet. Available here [Accessed 23rd Oct. 2018].