I agree with LL7970, my girl went into heat the day before her spay appt and the vet waited over a month to go ahead with the procedure. If they were to do the operation while in heat, she would unfortunately bleed out. Chances are your vet will not do it until they know for sure she is done. If they want to, you need to find another vet.
thanks, I'm going to call my vet and ask but generally with most question they haven't been very helpful, so I wanted to do some research beforehand
I worked for a vet for 4 years - the 2 doctors I worked for would not sapy a dog while she was in heat - - no matter what.
I would just say to call your vet and ask them - they would be able to tell you for sure - I thought I'd heard that they generally don't, but that may not be true...