I had the merina inserted 2 weeks ago and the dr said i don't need to check if it is in place, is the string short enough so i can still wear tampons?

Mirena IUD: Most physicians will cut the string of the IUD at the level of the cervix, so it does not cause irritation to a male. It would be difficult to feel in any case, and does not interfere with tampon use. If the IUD were to be expelled or moved by uterine contractions into the cervical canal, you would have pain and bleeding, and should see your gyn physician.

True: You do not need to check your string. If the IUD was coming out, you would have symptoms such as bleeding and strong cramping. In the US, most doctors cut the strings about 2cm long so that they can be grasped and used to remove the IUD when it is time to be removed. You can use tampons without any problem.