Her reproductive hormones are not active and there is an absence of estrus cycle activity; she is not in season. (thesprucepets.com)
They will have repeated cycles of estrus during the course of a year and may even go through periods of continuous heat. (cuteness.com)
There may be additional charges for non-routine surgery, which would include a pregnant or in estrus cycle (heat), infections, undescended testicles, false pregnancy, obesity or females that have had previous litters. (oc-paw.com)