If your dog is peeing on her bed during the night, it sounds like incontinence of some sort.
PLEASE call your vet, and take a urine sample in for analysis.
When my dog started wetting her bed at night, it turned that she had a bladder infection AND bladder stones that needed surgery.
Spayed dogs can also get "spay incontinence" and that can be treated with inexpensive hormones.
Please don't even consider putting this little outside for something she cannot control and get a vet appointment asap!