I had SPD with DD2 (now 2 weeks old) i found that for some reason my pain all but disapeared at around 37 weeks. I didnt do anything differently, just one day i woke up feeling great. I ended up have DD2 2 weeks early so i believe that the labour hormones had kicked in and had taken over the Relaxin hormones, I know this doesnt help at all but i also found that i had no SPD pain while i was in labour which i was really worried about becasue at times i could barely walk.