There is a small risk of uterine perforation on insertion and removal.
There may be cramping, pain or spotting after insertion.
After insertion you may have more vaginal discharge.
IUD’s tend to make periods longer, heavier and more irregular. With 10% of the women this is bothersome enough to have the IUD removed. So an IUD is not a good choice of birth control if you already have painful periods.
An IUD does not protect against STD’s. On the contrary, it may put you at a bigger risk of PID if you don’t use condoms and sleep with lots of guys or with one guy who sleeps with lots of girls.
It must be inserted and removed by a trained doctor.