I have already thought of lack of progesterone as she has been on the pill for years to regulate her irregular cycles. And I have already tried to suggest that maybe she has an imbalance of hormones. But, she does not agree.
I stand by what I said, however I repeat. You can not fix this! You have suggested and she has denied, does not surprise me at all. Puppy has a different idea and reason I would love to hear it.