What Causes Discharge Of Foul Smelling Fluid From Vagina?

have daughter with CP, spastic quadreplegia, started having what I though was horrid smelling urine. SHe is 22 now, started her first period on her 21st birthday, had three cycles and then quit. She weighed about 70 lbs then. Aug of last year she had a bowel operation, double twisted knot, in IC for a week. The bad smell went away but now returned with a vengence! Started about 3 months ago and it is even more putrid than before. She had some UI's and dealing with some yeast infections, but now I know it is not urine, it is fluid coming from the uterus, she can relay that to me and when I put her on the toilet is is so much fluid it sounds like she is urinating, but she is not. Her Doctor who is a DO, put her on birthcontrol pills, they have done a swab and urine culture and say there is a lot of hormones in it, but now the fluid is worse, I think it must be something else. She does have low thyroid and takes levothyroxine, and takes trazadone to sleep. She wears pullups as she cant control when she does urinate, I can put her on the toilet for BM's though. Any idea why or what is going on here???