I am considering taking her to a reproduction facility to try and get her bred. She is 16 this year, and her last foal was about 7 years ago. I have tried for a couple of years now, with different stallions, so I think she needs some work. I am getting 2 very nice Crabbet mares in spring. Will post when they are here.
A full repro work-up--culture and cytology, uterine biopsy, etc. would be a good place to start. One of my older broodies has developed fluid retention issues and low progesterone, but with close monitoring and treatment of the fluid during her breeding cycle and tracking of her progesterone levels (which led us to put her appropriately on Regumate) she is still in foal at 100+ days. I sure hope she carries to term, but it looks good so far.