Which among the following is TRUE about MIRENA?

The levonorgestrel-releasing IUS, Mirena, releases 20 mcg of levonorgestrel per day and is approved for contraception for up to 5 years. It achieves local progestin concentrations that are ~1000-fold higher than systemic levels. It has many contraceptive actions including thickening of cervical mucous, inhibiting sperm capacitation and survival, suppressing the endometrium and suppression of ovulation in some women. Irregular bleeding is common in the first few months following inseion because endometrial suppression takes several months to evolve. Bleeding is then markedly decreased and secondary amenorrhea can occur. Ref: Sass A.E., Kaplan D.W. (2012). Chapter 4. Adolescence. In W.W. Hay, Jr., M.J. Levin, R.R. Deterding, J.J. Ross, J.M. Sondheimer (Eds), CURRENT Diagnosis & Treatment: Pediatrics, 21e.