The Levonorgestrel IUD: Mechanisms, Effectiveness, Side Effects, and More

Nishi Kashyap
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Dr. Kaushal

Review medical content on WOW Rx Pharmacy, so that accurate drug use information is easily accessible to everybody.
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Levonorgestrel IUD

The Levonorgestrel IUD (Lng-IUD) stands out as a commonly chosen option for women seeking effective birth control.

This device offers women a long-lasting and convenient solution to prevent unwanted pregnancies. 

As per the Centers for Disease Control and Prevention data, about 14% of women aged 15 to 44, who used contraception, opted for an IUD from 2015 to 2017.

In this article, we will discuss everything about Levonorgestrel IUDs, including their mechanism of action, effectiveness, benefits, side effects, and interactions.

Our aim is to share insights with you about this hormonal IUD before you decide to use it for birth control.

About Levonorgestrel-releasing IUD

Levonorgestrel Intrauterine Device (IUD) is a small, T-shaped device inserted into the uterus.

It is an FDA-approved device for preventing pregnancy and managing Menorrhagia.

Menorrhagia refers to heavy menstrual bleeding that lasts for seven days.

Levonorgestrel IUD is available under common brand names, including Mirena, Skyla, and Liletta.

It is a form of birth control that provides long-term protection and can be reversed when needed.

Levonorgestrel-releasing IUDs do not protect against any Sexually Transmitted Diseases, including Chlamydia, Gonorrhea, or HIV.

Levonorgestrel IUD mechanism of action

Strings too shortSource: SOMNATH_MAHATA_from_GettyImages
IUD on white background

The Levonorgestrel IUD device works by releasing Levonorgestrel into the uterus. 

Levonorgestrel belongs to a class of medications called Progestins.

This thickens the cervical mucus and makes it quite difficult for sperm to reach the egg. 

Additionally, this IUD also changes the lining of the uterus, reducing its receptivity to a fertilized egg. 

In some cases, it may also suppress ovulation. This results in preventing pregnancy. 

The combination of all these actions makes the Levonorgestrel IUD a highly effective contraceptive method.

Do not try self-insertion of this device. It can result in serious consequences, including device expulsion, perforation during insertion, or risk of infections.


The effectiveness of the Levonorgestrel-releasing IUD in preventing pregnancies is exceptionally high. 

It is considered one of the most reliable forms of contraception available. 

A study published by the National Library of Medicine compared the effectiveness of Lng-IUD with Nova T (a copper-releasing IUD).

Researchers found that the 12-month net pregnancy rate for the Lng-IUD was lower (0.1 per hundred women) compared to Nova T (0.9 per hundred).

Both IUDs had similar rates of removal due to menstrual issues, but Lng-IUD reduced bleeding, leading to fewer or no periods. 

The study suggests that Lng-IUD is a highly effective contraceptive and a good option for long-term use.

Levonorgestrel IUD side effects

back painSource: Povozniuk from Getty Images
Back pain

Levonorgestrel IUDs are generally well-tolerated, but they can be associated with side effects. 

It is important to note that not everyone will face these side effects, and they can vary in intensity. 

Some common Levonorgestrel IUD side effects include the following:

  • Irregular bleeding or spotting
  • Changes in menstrual patterns
  • Cramping or pelvic pain
  • Acne
  • Headache
  • Back pain
  • Breast tenderness
  • Mood changes

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Drug interactions have the potential to change the effectiveness of your medicines. They can also raise the risk of serious side effects. 

Certain medications may interact with the effectiveness of the Levonorgestrel IUD.

Some of them include the following:

  • Ampicillin
  • Cefpodoxime
  • Doxycycline
  • Lopinavir
  • Nelfinavir
  • Rifampin

Keep a thorough record of all the products you use, such as prescription medications, over-the-counter drugs, and herbal supplements. 

Share this list with both your doctor and pharmacist. 

This can help your doctor to understand your overall health and potential interactions between different medications or supplements better. 

Additionally, discuss any concerns about food or alcohol interactions with your doctor. 

Seek approval from your doctor before starting, stopping, or changing the dosage of any medications. It will help ensure the optimal functioning of your treatment plan. 

Having open communication with your doctor is key to your well-being and the effectiveness of your contraceptive method.


UTIs in women are considered complicated if they are pregnantSource: tatyana_tomsickova from Getty Images
Don’t use during pregnancy

Levonorgestrel-releasing IUD may not show the same effectiveness for you all.

Here are some cases in which women should avoid using this device or should consult with doctors before its use:

  • It should not be used during pregnancy
  • Women with a history of PID may face an increased risk of complications
  • Women with certain uterine abnormalities should avoid this device
  • Severe liver disease may impact the metabolism of hormones, affecting the effectiveness of the IUD
  • Individuals with known allergies to any components of the Levonorgestrel IUD and unexplained vaginal bleeding 
  • Women with a history of or current diagnosis of Breast Cancer 

It is vital to note that this is not a complete list. 

If you or someone you know have any medical problems like blood clots, Migraines, or any health issue, it is strongly advised to consult with doctors before its use.

In such cases, doctors may give any alternative contraceptive options.


Levonorgestrel IUD is a highly effective and reliable contraceptive option. 

It is used to prevent pregnancies and manage heavy menstrual bleeding. 

This device works by altering cervical mucus, thinning the uterine lining, and, in some cases, suppressing ovulation. 

While generally well-tolerated, it may have some side effects, such as irregular bleeding, cramping, or changes in mood. 

Certain medications like Ampicillin and Rifampin possibly affect its effectiveness. 

It is advised to have open communication with healthcare providers about all medications, including over-the-counter and herbal supplements.

Taking necessary precautions is vital. 

Women with certain medical conditions, allergies, or a history of specific issues should consult with doctors before considering this contraceptive method.

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