It's definitely possible. 99.9% means 1/1000 women using it will still get pregnant. If you do get pregnant your dr will decide if it should stay in or take it out. Many times they just leave it in. It doesn't have to be out of place for it to happen. If you aren't sure if you are take a test. What makes you think you might be? That dang thing caused me nothing but trouble and a ton of symptoms until I took it out myself.
That's your call and no one elses. You are an adult and if you feel like you can take care of another human and start a family that's no one's business but you and the father