I have a similar problem going on here, and when bought a bed for our dogs, the first thing I did before putting it down was to take the zippered cover off, and put a heavy weight contractors trash bag around it, taped into place. This way the particular bad boy Impy can't soak through to the foam core. I whip the cover into the wash often, and bleach the trash bag and air dry before re-covering the bed. Maybe a good urine neutralizer might help? I wonder if your cats sense you're pregnancy and hormonal changes going on, and are reacting to that? Locking them into rooms separate from the areas they're peeing in may help...worth a try at this rate. (((HUGS))) and sympathy for your situation.