Hi there. I asked my DH what he though as he is an acupuncturist. Acupuncture for labour stimulates the hormones that bring on labour but may not necc bring on actual labour. Personally when I was in my pre-labour stage and having lots of irregular contractions, even acupressure brought on really strong ones within 10 mins but they still didnt regulate until my waters were broken. DH said that women should realise firstly that acupuncture is a form of intervention and secondly it won't force your body into labour.
Don't get me wrong, I had acupuncture when I was full term. I remember exactly what it was like waiting those last few weeks. My bub was still a week over. good luck!