Large clinical trials have decisively proven that the hormonal IUD is effective as a contraceptive for up to 8 years after insertion and effective as a treatment for heavy menstrual bleeding for up to 5 years after insertion. However, approved duration of use varies by country. Providers can counsel clients on both the approved duration for their country and the product’s clinically proven duration of efficacy, 8 years. Clients can remove the hormonal IUD at any time. Removal before the labeled duration is not dangerous, and while providers should offer counseling and support if clients present with undesirable side effects, they should not attempt to discourage clients from removing the method.

Mirena has a shelf life of 36 months (3 years) and Avibela has a shelf life of 60 months (5 years). Each hormonal IUD will have an expiration month and year printed on its package; the product can be inserted up through the final day of the printed month with no change in method efficacy or duration of use. Duration of use does not begin until the product is actually inserted, meaning that if Avibela or Mirena is inserted in the 60th or 36th month after manufacture respectively, a client can still use it for up to 8 years as a contraceptive without a reduction in efficacy. Insertion after the expiration date printed on the package is not believed to be dangerous, but the product will be less effective.

The hormonal IUD is one of the most effective contraceptive methods. It is over 99.8% effective after one year of use and over 99.3% effective from years 2-8. That means that out of 1000 people using the method for 12 months, 2 or fewer would be expected to become pregnant. This is slightly more effective than the copper IUD and equal in efficacy to Nexplanon.

Generally speaking, the hormonal IUD takes about 7 days to reach full efficacy. If the method is inserted within seven days of the first day of a client’s period or immediately following an abortion, miscarriage, or childbirth, the client will have contraceptive protection from those processes and does not need to use a backup method. If that is not the case, the client should use condoms or abstain from vaginal sex for seven days after insertion.

The hormonal IUD is highly effective for most users and in most circumstances, including post-partum and post-abortion use and use while breastfeeding. The hormonal IUD doesn’t interact with alcohol, other drugs (including GLP-1 agonists), supplements, or foods (e.g., grapefruit). Decreases in efficacy are generally caused by misplacement of the hormonal IUD due to uterine distortion, active infection of the reproductive system, method expulsion through the cervix, or uterine perforation. Providers must complete a medical history with their clients to ensure they do not have conditions that might cause uterine distortion (such as large fibroids), and are free from localized infection. Proper fundal placement of the hormonal IUD will limit the risk of expulsion or perforation, but providers should also instruct clients to regularly check the strings of their IUD to confirm that it is still in place.

In a clinical study on the hormonal IUD and heavy menstrual bleeding, the hormonal IUD caused a >95% reduction in median menstrual blood loss in the first 6 months of use in users without systemic conditions causing heavy bleeding, in contrast to a 21% reduction in users of oral hormonal therapy. The hormonal IUD has been consistently proven in both clinical and “real world” settings to be among the most effective options for reducing menstrual blood loss associated with gynecological conditions like endometriosis, fibroids, or adenomyosis. However, many users will experience irregular or more frequent bleeding in the first months of method use. While bleeding will reduce for almost all users over time, clients should be counseled on the potential for irregularity immediately following insertion.