How long ago was it that she had laminitis and how severe was it? How is she doing now?
I have known several mares that have had laminitis and are fine with carrying a foal, most were not so severe cases (caught early with little rotation) and one was moderately severe.
She has had it recently and has just come off meds, she has had rotation, slightly sunk on her forefeet but it could have been done before i had her as i was told by my farrier that she has had it before. She has had lammi due to being overfeed on her protiens etc, and her body could not cope, this is all on the vets advice of doing this to help her put weight on!!!! She has been off hard feed since i knew she had it 23 jan08, only on hay, thick bed plenty of water. She seems comfortable on all fours, Other vet that confirmed lammi said after check up last week she will be able to go out on the hardcore outside stable to stretch her legs. This is the 1st time she has had it with me. I had planned for her to be put in ofal this year.
I would be very wary of breeding from a mare who has had laminitis - if she is insulin resistant or has any other metabolic disorder that caused the laminitis in the first instance then it could happen again when her homones change as a result of pregnancy.
We lost a mare last year who developed insulin resistance - pre cushings, laminitis 100 days into her pregnancy & despite all treatment including pergolide, antioxidants, plastic shoes etc, etc had to have her PTS 6 weeks before her foal was due.