Mirena IUD: what it is, what it is used for, and how it works

 Mirena IUD: what it is, what it is used for, and how it works

Lena Fisher

If you are looking for information about contraceptive medicines or have talked to a doctor about it, you may have heard about the Mirena IUD. To help you and clear up all your doubts about this method, we talked to an expert on the subject. Follow us!

See also: Silver and copper IUDs: understand the differences between them

What is Mirena IUD?

First of all, it is important to explain what is IUD (intrauterine device), a contraceptive method that has four versions - one of them is the Mirena IUD: "It is a device that stays inside the uterus, which contains a hormone called levonorgestrel, a type of progesterone," says gynecologist Isabela Nelly Machado.

How does it work?

The Mirena IUD performs several actions in the uterus. In this way, contraception becomes very effective because, in fact, it does not only act in one way. hormone released constantly, which leaves the internal layer of the uterus (endometrium) very thin, and prevents a possible embryo implantation", comments the specialist.

In addition, because it is a hormone that hinders ovulation, it can increase the thickness of the cervical mucus, that secretion of the cervix, and prevent the sperm from meeting the egg.

How to place the Mirena IUD?

The insertion of the device can be done in the gynecologist's office, or in a hospital environment, when the doctor considers the need for anesthesia. Isabella Machado reinforces that the procedure is not complicated, as long as there is a previous evaluation of the woman's health: "Before placing the Mirena, it is interesting to observe if there is an infection that needs treatment or another abnormalityuterine that prevents the insertion of the IUD", he recommends.

Care after Mirena IUD insertion

Some care is important after the application, for example, monitoring the symptoms and the IUD strands, which are visible through the vagina by means of a routine gynecological exam: "We can visualize the IUD strands and know if it is well positioned. In addition, we monitor the symptoms. In some situations, we need to evaluate the positioning of the IUD by ultrasound.These measures are necessary, because if the IUD is not in the correct place, it can compromise the effectiveness and cause discomfort to the woman.

Mirena IUD advantages

Besides the prevention of pregnancy, the highlight goes to the practicality. After all, there is no commitment to take the medicine every day or every month. Other advantages:

  • After IUD removal, the return of fertility is immediate.
  • It can be used in other clinical situations, such as excessive menstrual bleeding.
  • Helps protect the endometrium during hormone therapy menopause .
  • There are no contraindications for patients at risk for diseases that worsen with estrogen, such as thrombophilias, as well as some types of migraine.
  • It does not require many tests before insertion - just make sure there is no pregnancy.

Even the Mirena IUD can be used during breastfeeding, since the puerperium restricts some contraceptive methods.

Disadvantages of the Mirena IUD

Although it has a list of benefits, there are some disadvantages related to the absorption of progesterone: "Although this absorption is low, there may be consequences, such as breast pain, a slight worsening in cases of acne, increased oiliness of the skin, and a slight increase in weight," points out the gynecologist.

Also, progesterone thins the endometrium a lot, which in some situations can be an advantage, but can cause some bleeding leaks (vaginal blood loss that occurs during the menstrual cycle, between one period and the next).

The Mirena IUD is currently approved by ANVISA for 7 years. Copper IUD which lasts up to 10 years, we can consider it a relative disadvantage," he says.

Is the Mirena IUD fattening?

Many women relate the Mirena IUD to weight gain. However, Isabella says the type of IUD does not influence fat gain: "There is no change in a woman's body composition due to the progestin hormone. But some women have a propensity for the progesterone to increase fluid accumulation. So this increases the weight on the scales, due to the increase in fluid", she explains.


The Mirena IUD needs medical indication and evaluation. Otherwise, it should not be used, because it is not for all women. Isabela advises to weigh the advantages and disadvantages to choose those that best fit the patient's profile.

"The absolute contraindication is if the woman is pregnant, or with a infection It is also not recommended when a woman has a distortion of the uterine cavity or other malformation where it is not possible to insert a device.

Source: Isabela Nelly Machado, gynecologist and coordinator of the Scientific Department of Gynecology and Obstetrics of the SMCC (Society of Medicine and Surgery of Campinas) .

Lena Fisher

Lena Fisher is a wellness enthusiast, certified nutritionist, and author of the popular health and well-being blog. With over a decade of experience in the field of nutrition and health coaching, Lena has dedicated her career to helping people achieve their optimal health and live their best life possible. Her passion for wellness has led her to explore various approaches to achieving overall health, including diet, exercise, and mindfulness practices. Lena's blog is a culmination of her years of research, experience, and personal journey towards finding balance and well-being. Her mission is to inspire and empower others to make positive changes in their lives and embrace a healthy lifestyle. When she's not writing or coaching clients, you can find Lena practicing yoga, hiking the trails, or experimenting with new healthy recipes in the kitchen.