She had another cat she took in as a stray have kittens a few years ago. The vet says to wait until the kitten are done nursing for the most part and mom isnt engorged at all. Typically they wean enough by 8wks for it to be good. Our vet is a bit unconventional though and that may not be typical. But a cat also will go out and get pregnant again by 4wks, so it has to be done soon if the mother goes out at all. That cat never showed signs of going into heat again and she had been newly pregnant when she was spayed. Thats when we learned how soon they go back into season after babies. We know now. I think mom is fine right now. We did the best math we could figure with the time that she came here, and all, and figure that if she dont have them by next week, then something isnt right. For now mom seems perfectly healthy and energetic, eating and drinking, using litter all normal. She dont look at all in distress. If seemed ill, or was sleeping too much or anything out of the norm that would be another story.