Passing out a symptom??

I have a cousin who is 21 and has a 2 year old son. She got the mirena placed after he was born and last year she started passing out. Drs found nothing wrong with her heart or any other test they ran. At one point she got better and the episodes subsided but now they are back and not letting up. She passes out 3 to 7 times a day and stays out for 3 to 10 minutes. Drs placed a monitor on her head and recorded brain activity. They said she is not having seizures and are still unsure of what is causing it. At first the Drs denied that the mirena could be causing it and told her if they removed it, insurance would not cover it nor any replacement birth control. Now they have decided to remove it on Wednesday and told her if her symptoms subsided to let them know!! Has anyone else had passing out as a side effect???