Hard to say because it doesn't happen all that often...or at least if it does then not many people know about it....but, I think is was Spain that won her final graded stakes in foal if I'm not mistaken, so they are obviouslt eligible to run well....still though, I can't see to where it would be a positive thing in most cases...if they go into heat and don't train to be shipped to a stud farm to be covered, I can't see how that ruitine change could help matters when it comes to her having to successfully race..