Adverse effects
Further information: IUD with progestogen and IUD with copper
Regardless of containing progestogen or copper, potential side effects of intrauterine devices include expulsion, uterus perforation, pelvic inflammatory disease (especially in the first 21 days after insertion), as well as irregular menstrual pattern. A small probability of pregnancy remains after IUD insertion, and when it occurs there’s a greater risk of ectopic pregnancy.
Substantial pain that needs active management occurs in approximately 17% of nulliparous women and approximately 11% of parous women.[32] In such cases, NSAID are evidenced to be effective.[32] However, no prophylactic analgesic drug have been found to be effective for routine use for women undergoing IUD insertion.[32]
Also, IUDs with progestogen confer an increased risk of ovarian cysts[citation needed], and IUDs with copper confer an increased risk of heavier periods.
Menstrual Cup companies recommend that women with IUDs who are considering using menstrual cups should consult with their gynecologists before use. There have been rare cases in which women using IUDs dislodged them when removing their menstrual cups, however this can also happen with tampon use.
Source: Wikipedia
A T-shaped plastic or metal devise in placed inside the uterus at the openings of the Fallopian tubes and left there for an indefinite period of time.
There are inherent puncture risks when it's inserted, risk of infection, risk of it shifting, etc. Couple this with the fact that young teen girls ARE STILL GROWING and have hormonal issues that grown women do not.
It is only in the past few years that women who have not had children but plan to eventually have used IUDs. Nobody really knows if a girl who has had an IUD for a decade or so will be able to become pregnant; however, the left doesn't really care, this is about an agenda and nothing more.