Can you tell me what number of days after you've had your mirena (levonorgestrel) iud coil can you have unprotected sex?

It depends: The Mirena (levonorgestrel) IUD is effective immediatly if it was placed within 7 days of the START of your menstrual period. If it was placed later than 7 days after your period started, you should use a back-up method, such as a condom for 7 days after insertion. If you were on birth control pills, you can have uprotected intercourse anytime after insertion but stay on your pills until your next period.