Mirena is one of the three Intrauterine devices (IUDs) available in Canada. This hormonal IUD is a long-term birth control solution for those looking for a maintenance-free contraception option. 

How does the Mirena Work?

The Mirena is a small, T-shaped plastic device that is placed into the uterus by a medical professional. The IUD releases the hormone progestin to prevent pregnancy. Once Mirena is inserted, it releases amounts of levonorgestrel hormone, thickening the mucus in the cervix while thinning the lining of the uterus and preventing sperm from entering, Mirena inhibits reproduction in the following ways:

  • alters the lining of the uterus to make it thinner, therefore making it more difficult for a fertilized egg to implant within the womb
  • prevents the release of an egg from your ovary
  • thickens the mucus in the cervix to prevent sperm from entering and fertilizing an egg

Why Mirena?

Once inserted, Mirena effectively prevents pregnancy for up to 5 years. Mirena is more than 99% effective, during the course of up to five years. The long term effectiveness of this device makes it an attractive option for those who do not want to conceive at present but may wish to do so in the future. Regular appointments/maintenance are not required once the device is in place. 

How do I Get the Mirena?

Like any other IUD, consultation, along with a prescription is required. On the day of your appointment, your medical professional will take you through the steps of the procedure. Use this opportunity to ask your medical professional any additional questions you may have.

Easiest way to fill your birth control prescription: Just a few clicks

What are the Benefits of the Mirena?

With a 99.6% success rate, one of the primary benefits of the Mirena is its rate of efficacy. Once in place, you can rest well knowing that you are nearly 100% protected from an unexpected pregnancy.

Additionally, once inserted, the Mirena requires little to no maintenance. Medical professionals generally recommend a follow-up visit 4-6 weeks after the procedure to ensure the device’s position is correct. After the follow-up appointment, the only maintenance required is a quick monthly check of the two thin strings attached to the end of the IUD. 

After a few months of use, the Mirena can decrease and even completely stop menstruation. Since the use of the Mirena can cause a complete cessation of a menstrual period, this IUD is an excellent choice for those who have heavy periods and extreme cramping and pain with periods. Eliminating this extra blood loss can also be advantageous to those suffering from anemia.

Does Mirena IUD make you gain weight? – Read on to find out

The long-term nature of the Mirena eliminates the need to “prepare” before intercourse. There is no need to worry about whether or not a condom is available, nor is there any need to worry about taking birth control pills regularly. When you are ready to conceive, removal of the IUD is a straight forward process. 

If you have the Mirena and decide to conceive, your ability to get pregnant returns soon after the removal of the IUD. If you do get pregnant and have a child, once confirmation from your healthcare professional is received, re-insertion of the Mirena is possible. Once reinserted (and after receiving clearance from your doctor), you can safely breastfeed your child. 

One of the main reasons why women choose Mirena is that once inserted, it can provide protection for up to 5 years.  Another reason why Mirena differs from the other IUDs is that it is most commonly used to treat heavy periods.

Benefits of Mirena IUD can be divided into the following two types:

Contraceptive Benefits:

  • Does not have side effects of birth control methods containing estrogen, such as the increased risk of clot formation
  • Can be used while breastfeeding
  • About 20% of women on Mirena stop having periods after three months of use
  • Can be removed anytime
  • A quick return to fertility after removing it
  • Does not need partner participation
  • Can stay in place for five years

Non-Contraceptive Benefits:

  • Lowers the risk of endometriosis, a condition where the uterine lining grows outside the uterus 
  • Reduces the intensity of menstrual pain
  • Prevents the risk of pelvic infection

Because of the benefits, Mirena is an ideal choice for women with:

  • Painful periods
  • Anemia
  • Fibroids
  • Endometriosis
  • Heavy menstrual bleeding
  • Abnormal growth of uterine lining, such as adenomyosis and endometrial hyperplasia

Disadvantages of IUD

Although IUD is a safe and effective contraceptive method, there are a few things to consider before you get it. For instance, there are a few disadvantages, such as:

  • Your periods may become heavier, painful, or longer. However, this will improve in a few months.
  • If you get infected while having the IUD fitted, you may get a pelvic infection.
  • It does not protect against sexually transmitted diseases. So, you may have to use a condom as well.
  • Many women stop using IUD because of vaginal pain and bleeding; however, these are uncommon side-effects.

Certain additional risks of using IUD are:

  • Pelvic infection: You are at a higher risk of pelvic infection for the first 20 days after IUD insertion. Your doctor may check for an existing infection before inserting IUD to prevent this risk.
  • Thrush: Getting an IUD fitted may slightly increase your risk of recurring thrush. If this happens, consulting your physician will help as they may suggest a different mode of contraception. 
  • Damage to the womb: In extremely rare cases, IUD may cause a hole in the uterus while getting it fitted. While this may be painful, usually there are no symptoms. If your physician or nurse fitting it is experienced, the risk of negligible. Consult your physician in case you are noticing any pain as the IUD may need removal.
  • Rejection: In rare cases, the IUD could be rejected and expelled by your womb, or it could move. If this happens, it is usually soon after it is inserted. Your physician will teach you how to check if the IUD is in place.
  • Ectopic pregnancy: If the IUD fails and you conceive, there is a slight risk of ectopic pregnancy.

What are the Disadvantages of the Mirena?

As any birth control method used, Mirena comes with a few potential cons. There may be a chance of ectopic pregnancy, and in rare cases, the perforation of the uterine wall or cervix. It may even cause severe infections, including pelvic inflammatory disease and sepsis if it’s not taken out on time.

The Mirena is a hormonal IUD that releases progestin into the body. This hormone can cause side effects in some individuals, including abdominal pain, headaches, changes in blood pressure, swelling of feet, face, ankles, etc.

While the Mirena may protect against pregnancy, it does not protect against sexually transmitted diseases (STDs). If you are not in a committed sexual relationship, it is still necessary to take additional measures to protect yourself.

The process of getting the IUD inserted may be considered a con for some. The procedure itself can be painful for some individuals. When the IUD procedure is complete, your medical professional may suggest that you take the remainder of the day off to rest and recover. Taking the remainder of the day off and missing an entire day of work may be a disadvantage for some.

While rare, it is worth noting that the uterus can get punctured during the insertion of the Mirena. Inserting the Mirena during postpartum menses increases the chances of this happening. 

Another rare occurrence of note is that some people report having their Mirena come out entirely or partially on its own (an event called expulsion). If this does happen, the IUD must be removed by a medical professional. 

Some common side-effects of Mirena IUD are:

  • Acne
  • Irregular bleeding
  • Pelvic pain
  • Headache
  • Breast tenderness
  • Mood changes

Other disadvantages include:

  • While inserting: Pain, dizziness, cramping, bleeding, and spotting for a few days after insertion:
  • During the first year: Irregular or longer periods.
  • Later years: Spotting or irregular periods.
  • During removal: Cramping and bleeding.
  • Expulsion of Mirena: The chances are more if you have prolonged or heavy periods, have never been pregnant, are younger than 20 years of age, or are inserted immediately after childbirth.

IUD Maintenance

This IUD is very low maintenance. You do not have to worry about using it incorrectly or forgetting to take it. Your physician will recommend you to check for the IUD string to ensure that it is not displaced.

Only in the following cases, you might be advised to get the IUD removed:

  • Endometritis, which is inflammation of the womb’s lining
  • Pain during sex
  • Pelvic infection
  • Severe migraine
  • Cervical or endometrial cancer
  • Increase in blood pressure
  • Exposure to sexually transmitted infection

Inserting Mirena IUD

Your physician will evaluate you before inserting Mirena IUD. You can choose to insert Mirena:

  • Immediately after delivering a baby
  • Immediately after terminating a pregnancy
  • Anytime during the menstrual cycle if you are not pregnant. (Doctor may ask you to take the pregnancy test to confirm that you are not pregnant)

You can consider taking non-steroidal anti-inflammatory medication, such as ibuprofen, before inserting IUD to prevent cramping.

Of note, if you get Mirena inserted more than seven days after your period starts, it is a good idea to use other contraception as a backup for a week. The Mirena is an excellent choice for those looking for an IUD. If you are interested in the Mirena, be sure to discuss with your medical professional to see if the Mirena is the right IUD for you.

Mirena Pros and Cons


  • It is over 99% effective in preventing pregnancy
  • It can be used for five years
  • It makes your period lighter
  • Immediate return of fertility after its removal


  • Hormones released by the IUD can have side-effects
  • It can expel out of your body on its own
  • It is expensive
  • Needs doctor’s assistance to insert; you cannot use it on your own

Benefits of Mirena

Apart from the benefits similar to other IDS, Mirena also has the mentioned additional benefits:

  • It lowers the risk of endometrial cancer
  • It manages symptoms of endometriosis
  • It lowers the risk of pelvic infection

How Does Mirena Work?

Mirena contains 52 mg of levonorgestrel and releases roughly 20 mcg of levonorgestrel per day that affects the lining of the uterus, thickens cervical mucus, and prevents ovulation. All these mechanisms prevent contraception.

It can also help in reducing heavy menstrual bleeding. Over the period of time, the device releases lesser hormones; it needs replacement after five years.

Mirena Effectiveness

Mirena IUD is more than 99% effective in preventing pregnancy. It is more effective than many other contraception forms, including condom, hormonal patch, pills, injection, or ring.

When used to manage heavy menstrual bleeding, it is effective in 90% of the cases within six months of its use. It is seen to reduce menstrual bleeding by more than half.

Read more about other birth control methods  here.

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