Mirena Coil: What are the pros and cons of this hormonal IUD

BlogContraceptive Coils

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Catherine Smith

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Mirena Coil: What are the Pros and Cons? 

The Mirena coil is a popular hormonal intrauterine device (IUD) used as a contraceptive option. It offers several benefits, such as its small size and long-term effectiveness. However, there are also potential drawbacks, including the need for a coil fitting specialist to insert it and the possibility of side effects. It’s important to weigh the pros and cons before deciding if the Mirena coil is the right choice for you.

Key Takeaways:

  • The Mirena coil is a small intrauterine device (IUD) used for contraception.
  • Pros of the Mirena coil include high effectiveness and long-term convenience.
  • Cons of the Mirena coil include the need for a professional to fit the device and its potential side effects.
  • The Mirena coil is highly effective in preventing pregnancy but does not protect against STDs.
  • Consult with a doctor to determine if the Mirena coil is the right option for you.

Pros of the Mirena Coil

This small T-shaped device offers several benefits as a contraceptive option.

1. It’s highly effective

With a 99% efficacy rate in preventing pregnancy. This makes it a reliable choice for individuals seeking long-term contraception. In addition to its high effectiveness, the Mirena iud is also a convenient option for those looking for a low-maintenance form of birth control. Once inserted by a healthcare provider, the IUD can provide protection against pregnancy for up to eight years without the need for daily pills or monthly trips to the pharmacy.

2. No regular maintenance or check-ups

Furthermore, the Mirena does not require regular maintenance or check-ups, unlike other forms of contraception such as the birth control pill or contraceptive patch. This can make it a particularly attractive option for individuals with busy lifestyles or those who may have difficulty adhering to a daily pill regimen.

Once inserted, it can stay in place for up to 8 years. This means you can enjoy peace of mind without the need for frequent replacements or daily reminders.

3. It’s so small you won’t feel it

Due to its size, it is typically not felt by the individual once it has been inserted by a healthcare provider. Additionally, the strings attached to the coil are left slightly longer so that they can be easily located for removal if necessary. This design feature contributes to the overall convenience and effectiveness of the Mirena Coil as a long-term birth control option.

4. Continuous contraception

The Mirena coil offers uninterrupted birth control, enabling carefree and spontaneous sexual activity. You can enjoy intimate moments without the ongoing worry of unexpected pregnancies.

5.  Easy removal

When you are ready to start a family, the Mirena coil can be easily removed by a qualified doctor like here at The Coil Clinic. This makes it a convenient choice for individuals who have future family planning in mind.

6. Cost-effective

While the upfront cost of a Mirena IUD may be higher than other forms of contraception, its long-lasting protection can make it a cost-effective option in the long run. Working out at around £5 per month or similar to a box of 12 condoms. 

In summary 

Pros of the Mirena CoilDescription
Highly effectiveThe Mirena coil boasts a 99% effectiveness rate in preventing unwanted pregnancy, providing peace of mind.
Low-maintenanceOnce inserted, the Mirena coil can remain in place for 5-10 years, eliminating the need for daily reminders or frequent replacements.
Small In sizeAbout the size of a paper clip, once inserted you won’t feel a thing
Continuous contraceptionWith the Mirena coil, you can enjoy spontaneous and worry-free sexual activity without constant concerns about unplanned pregnancies.
Easy removalWhen you’re ready to start a family, the Mirena coil can be easily and safely removed by a healthcare professional.
Cost EffectiveWorks out to be around the same price as a box of 12 condoms a month.

Cons of the Mirena Coil

While the Mirena coil has many benefits, it’s important to be aware of the potential drawbacks and considerations associated with its use. Understanding the cons can help you make an informed decision about whether the Mirena coil is the right contraceptive option for you. Here are some key points to consider:

1. Insertion by Healthcare Professional

The Mirena coil must be inserted by a healthcare professional, which may be seen as a disadvantage for some individuals. This requirement means that accessing the Mirena coil may involve scheduling appointments and additional costs.

2. Discomfort or Cramping

Following the insertion of the Mirena coil, some women may experience discomfort or cramping. This can typically be managed with over-the-counter painkillers, but it’s important to be aware that these temporary side effects are possible.

3. No Protection Against STDs

It’s important to note that the Mirena coil does not provide protection against sexually transmitted diseases (STDs). If STD prevention is a concern for you, it’s essential to consider additional methods of protection.

4. Possible Risk of Slippage

While uncommon, approx 1 in 1000, there is a small risk of the Mirena coil slipping out of place and causing a perforation. If you notice any unusual symptoms or suspect that the coil has moved, it’s important to contact your healthcare provider for further evaluation and appropriate action. This can take the form of a removal by ultrasound at a specialist clinic, or in the worst case, by keyhole surgery. Both are relatively quick procedures and you are usually in and out in the same day.

5. Possible Side Effects

Some women may experience side effects after getting a Mirena coil, such as pain, cramping, or changes in bleeding patterns. These side effects should be discussed with your healthcare provider to determine the best course of action.

It’s important to weigh the pros and cons of the Mirena coil, considering your individual needs and preferences. If you have any concerns or questions, consult with a healthcare professional to ensure you have all the information necessary to make an informed decision.

In summary the cons of the mirena coil are 

Fitting by Healthcare ProfessionalMay involve additional costs and scheduling appointments
Discomfort or CrampingTemporary side effects that can be managed with over-the-counter painkillers
No Protection Against STDsAdditional methods of protection should be considered if STD prevention is a concern
Possible Risk of SlippageUncommon, but should be monitored and evaluated if suspected
Possible Side EffectsPain, cramping, or changes in bleeding patterns may occur

Effectiveness of the Mirena Coil

As mentioned previously, the Mirena coil is a highly effective form of contraception, with a 99% efficacy rate in preventing pregnancy. It works by creating an inhospitable environment in the uterus for sperm and conception. The effectiveness of the Mirena coil can be attributed to its ability to perform multiple functions.

Thinning the uterine lining

When a mirena contraceptive coil is inserted into the uterus, one of the ways it works is by gradually thinning the uterine lining. This helps prevent the egg from implanting itself in the uterine wall and can also make it harder for a fertilised egg to attach and develop. By altering the environment within the uterus, the coil can effectively reduce the chances of you getting pregnant.

Thickening cervical mucus

Thickening of the cervical mucus is a common side effect of the Mirena coil. This thickening can make it more difficult for sperm to reach and fertilise an egg in the uterus. The increased viscosity of the mucus creates a barrier that prevents the sperm from entering the cervix and ultimately reaching the egg. By inhibiting this process, the Mirena coil effectively reduces the chances of fertilisation occurring, providing a reliable form of birth control for women. 

Halting ovulation

Depending on the type of coil, the Mirena coil may also stop ovulation, preventing the release of eggs from the ovaries. Without an egg, fertilisation cannot occur, further enhancing the contraceptive effect.

It’s important to note that while the Mirena coil is effective in preventing pregnancy, it does not protect against sexually transmitted diseases (STDs). Therefore, it’s essential to use additional means of protection if there is a risk of STD exposure.

Overall, the Mirena coil offers a high level of effectiveness in preventing pregnancy, making it a reliable contraceptive option for many women. However, it’s crucial to consult with a healthcare professional to determine if the Mirena coil is the right choice for your individual needs and circumstances.

Insertion and Removal of the Mirena Coil

The Mirena coil, should always be inserted by a specially trained healthcare professional. This ensures proper placement and reduces the risk of complications. The process typically takes just a few minutes and in most cases is relatively straightforward. 

During the procedure, the healthcare professional will gently insert the Mirena coil into your uterus using a speculum. You may experience some temporary cramping or discomfort during and after the insertion, this can vary in terms of severity but normally would be relieved by taking over the counter analgesia such as paracetamol or ibuprofen.

Once the Mirena coil is in place, it provides continuous contraception for a period of upto 8 years. If, at any point, you decide to start a family or if you want to switch to a different method of birth control, the Mirena coil can be easily removed by your doctor.

When it comes to removing the Mirena coil, the process is similar to the insertion. Your doctor will carefully locate and gently remove the coil from your uterus. The removal procedure is typically quicker and less uncomfortable than the insertion.


The Mirena coil, as a long-term contraceptive option, offers several benefits that make it a popular choice for many women. One of its key advantages is its high effectiveness in preventing pregnancy, with an efficacy rate of 99%. This means that the Mirena coil is a reliable form of birth control for those who want to plan their family or simply enjoy worry-free sexual activity.

However, it’s essential to consider the potential drawbacks of the Mirena coil. The need for professional insertion is a factor that may influence your decision. The procedure requires a healthcare professional, to carefully place the coil in your uterus. While this ensures proper placement, it may be a barrier for some individuals who prefer self-administered methods.

Additionally, it’s important to be aware of the possible side effects associated with the Mirena coil. While not everyone experiences them, some women may encounter pain, cramping, or changes in their bleeding patterns. These side effects are usually manageable and tend to diminish over time. However, it’s crucial to consult with a healthcare provider to address any concerns and determine if the Mirena coil is the right choice for you.

In conclusion, the Mirena coil offers a balance between effectiveness and convenience as a long-term contraceptive method. By weighing its pros and cons, and discussing your individual needs and preferences with a healthcare professional, you can make an informed decision about whether the Mirena coil is the best option for you.

Mirena Coil Frequently Asked Questions (FAQ)

What is a Mirena Coil?

A mirena coil is a type of intrauterine device (IUD) that is used for birth control. It is a hormonal IUD that releases the hormone levonorgestrel into the uterus to prevent pregnancy.

How does the Mirena Coil work?

The Mirena coil works by releasing levonorgestrel, which thickens the cervical mucus to prevent sperm from reaching the egg, and it also thins the lining of the uterus to prevent implantation.

How effective is the Mirena coil?

The Mirena coil has a 99% efficacy rate in preventing pregnancy. It works by creating an inhospitable environment in the uterus for sperm and conception.

What are the pros and cons of using a Mirena Coil?

Some pros of using a Mirena coil include highly effective contraception, lighter periods, and long-term usability. However, some cons may include side effects like irregular bleeding, the lack of protection against STDs, and the small risk of the coil slipping out of place.

What are the common side effects of the Mirena Coil?

Common side effects of the Mirena coil may include changes in menstrual bleeding patterns, cramping, bloating, breast tenderness, headaches and skin changes.  However, these side effects tend to settle after a couple of weeks. It is essential to discuss potential side effects with your healthcare provider.

How is the Mirena Coil inserted?

IUD insertion is a quick procedure performed by a healthcare provider in which the Mirena coil is placed inside the uterus using a speculum. It is essential to follow the proper insertion guidelines for effective birth control.

Can the Mirena Coil be used as emergency contraception?

The Mirena coil is not recommended for use as emergency contraception. It is designed for long-term birth control and should be inserted by a healthcare professional.

Where can I get the Mirena Coil Fitted

At our clinic based in Edinburgh, where we offer a fully comprehensive mirena coil fitting service, by a highly experienced and well regarded women’s health specialist doctor. 

Dr Catherine Smith

Dr Catherine Smith is the founder of The Coil Clinic. A GP and Women's Health Expert with nearly 20 years of experience. She is a BMS Certified Menopause Specialist