hmm i am not sure.. though i dont think SPD is an indicator of early labour likelihood? at least i wasnt told this!!
(your history could be though)

if you are worried i would spk with your midwife or dr - they would have more of an idea. i am a big physio advocate but i think you would get more reliable info on pre term labour etc from midwife or dr.

hope it doesnt get too bad...