Hi,
I just wanted to let you know that I went on a cruise when I was on my third trimester of pregnancy. Most cruise lines don't allow you to go when you are that far along, but Celebrity did. Anyway, I didn't need to take anything, as I did not get seasick at all. I did have to take naps, though, since I got overly tired easily. I recommend that you travel during the second trimester. That is when most women feel the best. Less morning sickness, and not too big yet.
Good luck.
MamaofEnS