last time i had a vacation trip when i was about 6-month-pregnant. this time i also plan to have a trip in Sep this year.
i think if health situation permits, having a trip is a good way to relax and memorable as you can take lots of pictures with your big tummy. the most important thing is to go to a safe a clean place, with good transportation system. and even better to do some research for emergency assistance (e.g. the location of hospital nearest to the hotel you will stay) - just in case.