I am a bit sceptical about s&s... I have no doubt it brings on contractions, but I don't know if it is enought to sustain labour.

Having said that I had one done at 5days post edd with DD#2 and I went into labour the next morning. However, I checked my cervix before I went to the dr and I could feel things had changed and told DP that I thought it wouldn't be too much longer...