Insurance & IUDs

Hello everyone! I have wanted to get an IUD for so long but have repeatedly run into the same problem: my parents are pious and would be heartbroken and disappointed if they found out I am having premartial sex; however the only insurance I have is through them. I'm 18 years old and know that having sex with my significant other is my own choice, but I really would like to spare my parents the "devastating" news and keep this to myself. Has anyone else had this problem? My insurance covers IUDs but it's sure to show up on the EOB, and I'm reluctant to fork over $500+ dollars for one :-( Please advise!