Not to make you worry in addition to the usual spay worries but I had Bitsy spayed a couple weeks ago and she got burned by the heating pad they used to keep her warm during surgery. I don't know how common it is for a vet to use a heating pad and think that burns are very uncommon if they do use it, almost unheard of, but it did happen to Bitsy. Seems if something wierd is going to happen...it's going to happen to ME
Probably just a fluke but you might want to ask your vet if they use one. Hope everything goes well!! Post and let us know how she is doing! Otherwise, Bitsy did great!!!