We have two female cats. Both were spayed about a year ago and yet one of them still comes into heat every few months. It's getting so annoying. She squeals to go out and then squeals because the tom cats are pinning her down. We have 3-4 tom cats around the house each time and they have sprayed the front and back doors a few times which stinks Had a google to see if there is something the vet can give her to stop it and it just seems to point to the fact the spay was incomplete. Has anybody else had this problem? Any advice would be greatly received.