
When did she have her last litter? At 7 with previous whelping problems risking her again seems unnecessary, as she should have produced something for the next generation with 3 litters already?
To be honest after having had two C sections she really ought not to be bred from again. Her uterus will have been weakened from the previous C sections, and having had two this points to some problem with natural whelping so really you ought not to breed from her again.
Could you live with yourself if something happened to her, like a ruptured uterus?
Why not have the Alizin injection or have her spayed now.