What is the Mirena (levonorgestrel) intrauterine device (IUD)?

From the Guidelines

The Mirena intrauterine device (IUD) is a highly effective, long-acting reversible contraceptive that can be recommended for most women seeking reliable birth control, with a failure rate of less than 1% 1.

Key Benefits of Mirena IUD

• It is a T-shaped plastic device containing levonorgestrel, a progestin hormone, which is released slowly into the uterus over a period of up to 7 years 1.
• Mirena works primarily by thickening cervical mucus to prevent sperm from reaching the egg, thinning the uterine lining, and partially suppressing ovulation.
• It is more than 99% effective at preventing pregnancy, making it one of the most reliable contraceptive methods available.
• Mirena can also be used to treat heavy menstrual bleeding and may provide protection for the endometrium during estrogen therapy.

Insertion Procedure and Side Effects

• The insertion procedure is quick, typically taking only a few minutes in a healthcare provider's office, though patients may experience cramping during and after placement.
• Side effects can include irregular bleeding or spotting in the first 3-6 months, which usually improves over time, with many users experiencing lighter periods or no periods at all 1.
• Mirena does not protect against sexually transmitted infections, so condoms are still recommended for those at risk.

Special Considerations

• HIV infection is not a contraindication to IUD use, and the use of an IUD in the context of HIV infection is classified according to CDC US medical eligibility criteria for contraceptive use as category 2, meaning that HIV is a condition for which the advantages of using the IUD generally outweigh theoretical or proven risks 1.
• The use of an IUD by an individual with advanced HIV disease is classified as category 3, meaning that risks generally outweigh benefits, including the theoretical risk of infection with IUD insertion.
• It is essential to weigh the benefits and risks of Mirena IUD use in each individual patient, considering their medical history, lifestyle, and personal preferences, to ensure the best possible outcome in terms of morbidity, mortality, and quality of life 1.

From the Research

Mirena Intrauterine Device Overview

• The Mirena intrauterine device (IUD) is a levonorgestrel-releasing system that provides highly effective, long-term contraception 2, 3, 4, 5, 6.
• It is approved for 5-year use, but studies have shown that it can be effective for up to 8 years 5.

Contraceptive Efficacy

• The Pearl index for the Mirena IUD is 0.1, indicating a very low failure rate 2.
• The cumulative failure rate over 8 years of use is 0.68% 5.
• Extrauterine pregnancies are rare, occurring in approximately 1 in 5000 users per year 2.

Therapeutic Effects

• The Mirena IUD reduces menstrual blood flow and can lead to amenorrhea in some users 2, 3, 4.
• It can also decrease dysmenorrhea and has been shown to be effective in treating severe dysmenorrhea associated with uterine myoma, endometriosis, and adenomyosis 3.
• The IUD may also decrease the growth of fibroids and reduce the risk of pelvic inflammatory disease 2.

User Satisfaction and Safety

• The Mirena IUD is well accepted by users, with typical annual continuation rates above 80% in clinical studies 2.
• The most common adverse events associated with the IUD are treatment-emergent adverse events, with 68.8% of participants experiencing at least one event 5.
• The discontinuation rate is approximately 38.4%, with the most common reason being desire for pregnancy 5.

Bleeding Patterns

• The Mirena IUD can lead to a decrease in menstrual bleeding, with approximately half of users experiencing amenorrhea or infrequent bleeding after 8 years of use 5.
• The IUD can also cause an initial increase in bleeding and spotting, but this typically resolves within 3-6 months 2.