What Are the Benefits and Risks of the Levonorgestrel-Releasing Intrauterine System?

Levonorgestrel-releasing intrauterine system (LNG-IUS) is widely recognized by women as an effective intrauterine contraceptive device; however, its benefits extend well beyond contraception. While the LNG-IUS offers numerous advantages, it is not without potential side effects. Below, we provide a detailed overview of the benefits and drawbacks of the levonorgestrel-releasing intrauterine system.

Benefits of the Levonorgestrel-Releasing Intrauterine System

The levonorgestrel-releasing intrauterine system is a slow-release intrauterine device containing a synthetic progestin. Once inserted into the uterine cavity, it releases 20 micrograms of levonorgestrel daily. The resulting local accumulation of progestin suppresses pituitary gonadotropin secretion, inducing a hypoestrogenic state that inhibits endometrial proliferation—thereby effectively alleviating symptoms such as dysmenorrhea and menorrhagia. The LNG-IUS is primarily indicated for the treatment of adenomyosis, endometriosis, menorrhagia, and endometrial polyps, and may also serve as a long-term contraceptive option for young women.

Drawbacks of the Levonorgestrel-Releasing Intrauterine System

1. Ectopic Pregnancy

Women with a prior history of ectopic pregnancy, tubal surgery, or pelvic infection are at increased risk for ectopic pregnancy. Among LNG-IUS users, the incidence of ectopic pregnancy is approximately 0.06 per 100 woman-years—a rate higher than that observed with conventional intrauterine devices.

2. Cessation or Reduction of Endometrial Thickening

The LNG-IUS releases a low daily dose of levonorgestrel directly into the uterine cavity, thereby halting or significantly reducing endometrial thickening and menstrual bleeding. This amenorrhea—which occurs in some LNG-IUS users—is typically transient and resolves spontaneously after device removal, with normal menstruation resuming thereafter.

3. Delayed Follicular Atresia

The contraceptive effect of the LNG-IUS is predominantly mediated through local action. In reproductive-age women, ovulation typically proceeds normally within the menstrual cycle. Approximately 12% of LNG-IUS users develop enlarged follicles resembling physiological cysts, which usually resolve spontaneously within two to three months. However, recurrent occurrences may predispose to serious complications such as large ovarian cysts.

We have now concluded our discussion on the benefits and drawbacks of the levonorgestrel-releasing intrauterine system. We hope this information proves helpful. Wishing you a joyful life and good health!