I have had my Mirena IUD for 4 weeks now. About a week ago, my strings vanished. They were very short in the first place - I could only feel a couple millimetres poking out of my cervix. I went to the clinic panicked when I could no longer feel the strings. The doctor checked with a speculum and said he thought he could see the end of the string but wasn't sure. He referred me for a pelvic ultrasound which will take place on Monday March 11th. I am pretty sure my Mirena hasn't expelled as I checked the strings at night, then after I had intercourse with my boyfriend, I checked the strings the next morning and they were no longer there. I did not go to the bathroom in between, and I have checked the toilet before flushing every time since. This has made me very nervous. My doctor said she has been inserting IUDs for 20 years, and didn't even mention strings after insertion. She just said that neither my boyfriend nor I should be able to feel it and that I only need to come for a follow up if I have unusual pain or bleeding. I got it inserted on my period and now I am due for another. I bled every day after insertion, gradually tapering off. The bleeding started up again for about 3-4 days before my expected period and now is barely spotting. Should I consider this a missed period? We have continued to use condoms and have barely come into contact without one (once, he was inside me for a couple seconds without one but we stopped). This was a couple days before the strings disappeared. We have been very careful with condoms since the strings went AWOL. I took a pregnancy test on the first day of my missed period and it was negative. I am just very nervous because I have always had very regular, heavy periods and now I have barely any bleeding. I know this is normal on Mirena but I thought it would take longer for that to change? Could it be because I bled for so long after insertion? And has anyone ever heard of a doctor purposely cutting the strings very short? Because it seems that was intentional. Any reassurance would be helpful because I am far too young (18) for a baby and my boyfriend and I are both college students living on our own without the financial means to provide for a child. I am also on medication that is thought to cause birth defects.