I don't know if it caused it really, but I had really spicy nachos 11 hours before my water broke. They weren't spicy enough to cause any irritating though, so probably a coincidence.

Walking and bouncing on a birth ball.

Water broke on its own with both of my kids. First time, water breaking did not start labor so i was induced. Second time, labor started within 30mins of water breaking and baby was born 4 hours later.