Your cat is trying to tell you something. Have you checked her out with your Vet? If she doesn't have any health problems, it's a behavior problem. Have there been any changes in the household? New people or pets? Remodeling? New litter or a change in litterbox location?

I have 12 cats; more than one of them pee inappropriately. I just don't know which ones. In desperation, I contacted a pet psychic. She told me the problem was "too many cats". So I just clean up with Simple Solution every time. If I catch someone in the act, a loud yell stops them. I will NOT euthanize for this. I spend a lot of time tracking down smells and obliterating them. Fortunately, my bed has only been the target once.

Until you know why she is doing this, put a plastic shower curtain on your bed or close the bedroom door at all times.