I cant find my old thread but I *think* I started leaking around the 14 week mark. Something like that anyway, it was very early. I couldn't resist having a squeeze and picking off any crusty bits either. Lol
I dont know about the pre- term labor bit but despite all my playing with em, DS was born at 37+3.
I did have a go at the nipple stimulation on 37+1, my waters broke the next morning and the morning after that he was here, so maybe there is something in it, but I think I read that nipple stimulation only works if bub is ready to come? Definately check that though.
HTH