I get strong BH - even my midwife is surprised by how hard they are if they come on whilst she's measuring/palpating - which have started from 16w each pregnancy.
And over the past few weeks they've definitely increased in intensity, which is understandable as I'm now 38+4.
But just today they're accompanied by what I can only describe as period pain, which starts with the BH and stops when the BH stops.
I wondered if it might be digestive
but the coincidence is just too much.
Ideally I'd prefer not to be in labour just yet ... so please tell me you had this for days/weeks before delivery. 
The pathetic thing is that this is DC3, DC2 is only two and I just don't remember what labour was like 