Re: Contractions in the evening at 18wks?
The general rule is to go get things checked out if you have more than 6 contractions in an hour - but for me, my BH contractions will come for an hour or 2, every 5-10 minutes, and they're painful, my whole belly tightening. This is later in my pregnancies, I mean.
Right now, I only get them every now and then, but they are painful or at least uncomfortable. It's still my whole uterus/belly that gets hard with them.
If nothing else comes along (like any weird discharge or something) I would just try drinking lots of water and making sure to put your feet up when you can through the day. I would just mention them at your next appt and see what is suggested.