Is it apparent that you are pregnant? Then I would have a doctor's note to show during check in at the pier if they question you. Some women show more than others. When I was 3 months along, I took a pregnant friend who was in labor to the hospital. The delivery staff thought I was the one in labor. True story!!! I wore maternity clothes at 6 weeks. At 23 weeks, the only way I could have travelled was with a doctor's note.
Leslie