well the bone scan will light ya up if you have any inflammation, thats is a good sign, you do have the signs for AS, what kind of arthritis are you already dx'd with??? that can be a factor as well, im sorry to say but it took 20yrs before i was diagnosed and by then my si's were totally fused my round spine was now square and spurs were growing towars each other, as everyone one has already mentioned it will be up to your doc about how to treat you, congrats on the wee one.....oak