Attitude was spayed while in heat. My vet didn't charge me any extra to have it done. They might have just been cutting me a break though since I called in in a panic to get her done. My 'definitely male' cat(according the the vet) was definitely NOT male and Nuts decided to prove that when the 'Tude went into heat(I had had my suspicions but I didn't think she'd go into heat at 5 months old, I was going to have her done at 6 months.) I think they were extra understanding since they knew I had an unaltered male. I think it helped that I had figured it out by looking down and finding Nuts on top of the 'Tude, who was thoroughly unimpressed. I thought I was bringing to unaltered males into a house with an altered female not an unaltered male and unaltered female, I trusted the vet as to what sex Attitude was. I think it also helped that they know both are leukemia positive and I needed to do the responsible thing by not bringing any more positive kittens into the world. Attitude had also been in heat less than 24 hours, Nuts let me know very quickly that his sister was in heat.
Spaz was in heat when I got her done(she was never NOT in heat and she had escaped the day before and went into heat the next day and I was NOT having kittens.)
They can do a spay at anytime really. They can spay a pregnant cat. When we had our ferals done one was in heat, one was pregnant, and the other was neither. The neither one had the roughest recovery, all the others could have been released the same night(Mama couldn't due to rain they didn't want her incision getting wet the same day as doing it, she was in heat.) Biter was all messed up and as i said she wasn't in heat or pregnant. Goldie was 2-4 weeks pregnant and she was up and ready to go when she got back and was happy to get out of the kennel that night and was back to climbing trees and climbing the latticework to get on the roof the next day, not to mention nursing the kittens. Her and Biter fed and took care of whatever kittens wanted to nurse or needed cleaned so we have no idea of which one had which of the 9 kittens from the pre-spay summer litter that gave me Attitude and Nuts.
It's crazy that they won't do a cat in heat. Never heard of a vet that wouldn't.
Taryn