What is Mirena Birth Control? Pros & Cons, Contraindications, Side-Effects

Intrauterine contraceptives (IUDs) have been used since the middle of the last century. They quickly found popularity among women because of their positive qualities: the lack of a systemic effect on the female body, high efficiency, and ease of use. The IUD does not affect the quality of sexual contact. It is established for a long period of time and practically does not require control. The most popular intrauterine hormonal contraceptive is Mirena Birth Control.

What is Mirena Birth Control?

Mirena intrauterine device (IUD) is a T-shaped device that is placed in the uterine cavity to achieve a contraceptive effect.

There are 2 types of IUDs: devices containing copper or silver and devices containing hormones. IUDs containing hormones are considered to be more effective, so now they are used more often in gynecological practice.

Mirena birth control is a device containing the levonorgestrel hormone. Every day Mirena releases a certain small dose of this hormone into the uterine cavity. The hormone affects only the uterus and is practically not absorbed into the blood. This significantly reduces the risk of side effects. There is no suppression of the ovaries. What’s more, Mirena’s birth control has a therapeutic effect.

The main hormonal component of Mirena IUD is ​​levonorgestrel (gestagen). Mirena contains 52 mg of levonorgestrel. This hormone is often used in various birth control pills. The device releases roughly 20 mcg of levonorgestrel per day. Over time, the amount of the hormone decreases. Therefore, Mirena’s IUD needs to be changed in five years.


How Effective is Mirena Birth Control?

It’s been more than 20 years since the appearance of Mirena’s birth control. During this time, Mirena showed high efficiency in preventing unwanted pregnancies.

According to the statistics, during one year of Mirena’s use, only 1 out of 500 women got pregnant. Compared to birth control pills, Mirena IUD is a more reliable contraceptive.

The Effect of Mirena Birth Control on the Body

Contraceptive system Mirena begins to release levonorgestrel into the uterus immediately after the insertion. The hormone enters the cavity at a rate of 20 μg a day. After 5 years this figure is reduced to 10 μg per day. The IUD has a local effect. What’s moe, levonorgestrel almost entirely concentrates in the endometrium. In the muscular layer of the uterus, the concentration is no more than 1%. In the blood, the hormone is contained in microdoses.

After the insertion of the Mirena birth control device, the active ingredient enters the blood in about an hour. The highest concentration is achieved in 2 weeks. Still, this figure may vary significantly depending on the weight of a woman. The active substance splits in the liver. Then it is excreted by the intestine and kidneys.

Mirena Birth Control: How Does it Work?

The contraceptive effect of Mirena IUD is mainly related to the effect of levonorgestrel. The introduction of a fertilized egg is not done due to the bad activity of the uterine epithelium. In this case, the natural growth of the endometrium is suspended and the functioning of its glands reduces.

Also, Mirena IUD hampers the mobility of sperm in the uterus and its tubes. The contraceptive effect of the drug increases the high viscosity of the cervical mucus and the thickening of the mucous layer of the cervical canal. As a result, it complicates the penetration of sperm into the uterine cavity.

The Pros and Cons of Mirena Birth Control

Mirena IUD has its advantages and disadvantages. It is not suitable for all women. After learning about the pros and cons of Mirena, you will be able to decide whether this method of protection against pregnancy suits you.

The Pros of Mirena Birth Control

  • Having inserted Mirena IUD once, you no longer need to take care of contraception. It’s more convenient than other methods, for example, you need to take birth control pills every day in order to keep the contraceptive effect.
  • You don’t need to change Mirena birth control frequently: you can use one device up to 5 years in a row.
  • Either you or your sexual partner won’t feel the IUD during sexual contact.
  • Unlike the pill, Mirena birth control does not increase appetite and does not cause water retention in the body. Therefore it doesn’t cause weight gain.
  • It can be used as a treatment for Adenomyosis (Endometriosis of the uterus) and for uterine myoma.
  • The IUD reduces blood loss and pain during menstruation.

The Cons of Mirena Birth Control:

  • It is impossible to insert the IUD independently. You need to visit a gynecologist.
  • Unlike condoms, Mirena birth control does not protect against sexually transmitted diseases (including chlamydia, gonorrhea, HIV infection, herpes, etc.). So it is not suitable for women who have sex with unfamiliar partners.
  • In the first 4 months after the insertion of the Mirena device, the woman has an increased risk of inflammation of the fallopian tubes.
  • Mirena birth control may cause long-lasting spotting in the first months after the insertion.
  • It may cause irregular menstruation in the first months after the insertion.
  • The device may also cause a temporary cessation of menstruation but, after the removal of the spiral, the menstrual period returns within 1-3 months.
  • Mirena birth control may become the reason of the appearance of follicular ovarian cysts. These cysts are not health-threatening and rarely require any treatment. Usually, they dissolve themselves within a few months.
  • There is a risk of an inconspicuous loss of Mirena device which can lead to unwanted pregnancy.
  • If pregnancy occurs during using the IUD there is a risk of ectopic pregnancy and miscarriage at an early stage.

At What Age can Mirena IUD be Inserted?

Among gynecologists, there is an implicit rule that only women who gave birth can use IUDs. Nevertheless, there are studies in which nulliparous women and even girls under the age of 18 used IUDs. Intrauterine devices were effective and safe.

According to official recommendations, girls who have not yet had their first menstruation and women older than 65 years have contraindications to Mirena birth control.

And yet, most gynecologists will probably deny inserting the IUD if you are younger than 25 and you have not given birth yet.


There are not so many contraindications to inserting Mirena birth control but they still exist:

  • Pregnancy or alleged pregnancy
  • The inflammation of the vagina or the cervix
  • Chronic genital tract infections
  • The inflammation of the urethra or bladder
  • Precancerous or cancerous changes of the cervix
  • Cancer or suspicion of breast cancer
  • The inflammation of the uterus (endometritis) after childbirth or abortion during the last 3 months
  • Anomalies of the development of the uterus
  • Submucosal myoma of the uterus

Mirena Birth Control Side-Effects

After inserting Mirena IUD, there may be undesirable side-effects:

  • Headaches and migraines
  • Mood swings and depression
  • Oily skin
  • The appearance of acne
  • Hair loss
  • Excessive growth of facial and body hair
  • Prolonged spotting, irregular period
  • The cessation of menstruation

Also, your doctor can recommend the removal of the Mirena Birth Control if you have severe headaches, an uncontrolled increase in blood pressure, or heart pain.

How is the Mirena Birth Control Inserted?

Insertion of the IUD is possible only in the gynecologist’s office. Before that, the doctor examines you and gets acquainted with the results of all the performed examinations. If there are no contraindications the doctor can start the procedure of inserting Mirena birth control immediately.

It is better to insert the Mirena IUD within the first 7 days of the menstrual cycle (the first day of menstrual is the first day of the cycle). The probability of pregnancy is the lowest during these days.

Does it Hurt?

The procedure of inserting the Mirena birth control seems unpleasant but most women do not experience severe pain. If your pain limit is too low, tell your doctor about it. A physician can inject an anesthetic into the cervix to reduce its sensitivity.

What Factors can Reduce the Contraceptive Effect of Mirena Birth Control?

The only significant factor that reduces the effectiveness of Mirena IUD is its inconspicuous fallout. Incorrect insertion of the IUD can also reduce its effectiveness but if your doctor still has doubts about the correctness of the insertion they will recommend that you go through an ultrasound or replace the device.

Drugs, alcohol, indigestion do not reduce the effectiveness of Mirena’s birth control.