Hello, and I hope I can help you today. I am concerned that your Mirena may have dislodged during sex or that it may have scraped or injured your uterus. After a c-section, your uterus can be attached to the area on your skin where the scar is on the inside so it is not unusual to feel pain from your uterus under your scar. As long as you do not have any fever, nausea or vomiting, or severe, whole abdominal pain, especially if you start to feel pain around your navel or your right shoulder, you can wait until the morning to be evaluated by your OBGYN. If you were my patient, I would first check the string of your IUD and then send you for a detailed ultrasound of your uterus to check the position of the Mirena. If these tests are not immediately available to you at your doctor s office you may want to consider going to the ER however many emergency rooms may not have ultrasounds available at night and you may not be able to get an answer until the morning. I suggest you call the doctor on call for your OB doctor (if they have a night time answering service) and ask what they recommend. They will know the best way to proceed in your area and with the resources they have available in their office. I hope my advice was helpful to you and that I have answered your question adequately today. Best wishes, Dr. Brown