Before insertion, a pelvic exam is performed to examine the shape and position of the uterus. A current STI at the time of insertion can increase the risk of pelvic infection. However, routine screening for gonorrhea and chlamydia prior to insertion is not recommended. If a person needs screening and there is no evidence of infection on examination or has been previously screened, insertion of the IUD does not need to be delayed. Insertion
During the insertion, the vagina is held open with a speculum, the same device used during a pap smear. A grasping instrument is used to steady the cervix, the length of the uterus is measured for proper insertion with a uterine sound for decreasing chance of uterine perforation with the IUD, and the IUD is placed using a narrow tube through the opening of the cervix into the uterus. A short length of monofilament plastic/nylon string hangs down from the cervix into the vagina. The string allows physicians and patients to check to ensure the IUD is still in place and enables easy removal of the device. Mild to moderate cramping can occur during the procedure, which generally takes five minutes or less. Insertion can be performed immediately postpartum and post-abortion if no infection has occurred.Misoprostol is not effective in reducing pain in IUD insertion. Removal
Removal of the device should also be performed by a qualified medical practitioner. After removal, fertility will return to previous levels relatively quickly. One study found that the majority of participants returned to fertility within three months.
Cancer
According to a 1999 evaluation of the studies performed on progestin-only birth control by the International Agency for Research on Cancer, there is some evidence that progestin-only birth control reduces the risk of endometrial cancer. The IARC in 1999 concluded that there is no evidence progestin-only birth control increases the risk of any cancer, though the available studies were too small to be definitively conclusive.Progesterone is a hormone in the endometrium that counteracts estrogen driven growth. Very low levels of progesterone will cause estrogen to act more, leading to endometrial hyperplasia and adenocarcinoma. These effects can be minimized if treated with progestin, but not in very many cases. Estrogen and progesterone have an antagonistic relationship. Estrogen promotes the growing of endometrial lining, while progesterone limits it. In the case of endometrial cancer, progesterone can negatively regulate estrogen driven growth. Tumors formed are correlated with insufficient progesterone and excess estrogen. In patients with endometrial cancer who use progestin releasing IUDs concluded mixed results. A 2020 meta-analysis by Livia Conz et al. estimated that users of levonorgestrel-releasing systems had an increased breast cancer risk in general (with an odds ratio of 1.16) and higher risk for those over age 50 (odds ratio 1.52), and suggested balancing this risk against the known benefits of long-term use. Researchers cautioned against causal interpretation from this study, citing confounding effects, methodological concerns and a 2020 meta-analysis of randomized controlled trials which showed no increased risk. Bone density
No evidence has been identified to suggest Mirena affects bone mineral density (BMD).