Hi Moofa,
How are you doing? When I was very overdue with my 1st the mw told me that sex may help to induce labour (it didn't!!!) but when I had my 2nd I found it brought on contractions - only in the last couple of weeks though.
I really don't think there is anything to worry about at this stage. I'm a bit nervous about it at the mo. because I had a little blood in the discharge after our last encounter but there again it is probably due to the fact that I keep getting thrush and am a bit sore!!! Never had any probs with the first two though.
Take care