Yes, you can absolutely go on a cruise during your first trimester, and for many expectant mothers, this is actually the most flexible time to sail. Most major cruise lines, such as Royal Caribbean, Carnival, and Disney, allow pregnant passengers to board as long as they have not entered their 24th week of pregnancy by the end of the voyage. During the first trimester, you are well within this safety window. However, there are practical considerations to keep in mind, primarily the potential for "morning sickness" being exacerbated by the motion of the ship. It is highly recommended to book a mid-ship cabin on a lower deck where the vessel's movement is felt the least. You should also consult with your OB-GYN before booking to ensure you don't have a high-risk condition and to get a "fit to travel" letter, which some lines may request. It is also vital to check the itinerary for "Zika-risk" areas, as the CDC still advises caution for pregnant women in certain tropical regions. As long as you stay hydrated, avoid raw seafood at the buffet, and listen to your body's need for rest, a first-trimester cruise can be a wonderful "babymoon" before the physical limitations of the later stages of pregnancy set in.