Congratulations, by the way!  Most cruise lines will not allow you to board if you are at your 24th week or starting your 24th week while on the cruise.  A medical certificate is required by the airlines for travel within four weeks of delivery for most domestic flights and within 30 days of delivery for an international flight.  Your Unique Travel Advisor will make sure you have the most-up-to-date information necessary to travel while pregnant.  Of course, you always want to consult with your doctor prior to traveling.