My son (who bought a house across the street from me) acquired a young female kitten. Her spay is scheduled for this upcoming Tuesday (tomorrow), but over the weekend she started showing signs of having gone into heat (vocalizations, posturing). As far as I know, there's no reason the spay can't go forward as scheduled--but I've seen some statements that it will "cost more" with no clear indication as to how much more. Does anyone know, or it it something that's strictly case by case?