The first thing to understand is that every pregnancy is different. Some women have it easy during pregnancy, while others have a couple more struggles. It is always a good idea to talk with your doctor or midwife before continuing to boat. However, also understand that sometimes your doctor needs a little education on what kayaking is and what we actually do when we get in our boats. Listen to your body! Know when to take it easy.
Next is river selection. At the beginning, paddle what you want. I was able to playboat and compete with everyone else. It actually felt better to be in my boat than it did to be on land. As time went on I realized that instead of dropping waterfalls and boofing even 10ft drops, I felt more comfortable on easy class IV, and just being on any river with friends helped with my sanity.
Another thing to think about is boat selection. Some people like the volume of a creek boat as they got larger, however I felt controlling the swing weight of a creek boat was a little much on my body. I actually prefer my playboat. Either borrow a playboat that is one size bigger than usual, or be prepared to sit a little lower than you are used to in the water. You will just have to get good at bracing.
Have I mention abs yet? Well, those go on vacation. You may find you will be using more hips and your paddle to control where you boat is going. Rolling in late pregnancy becomes a lot more difficult simply because you may not be able to get off the back deck.
Now lets think about gear. Nothing will fit. You might spend 2 hours looking through your boxes of old stuff, and you might find something that fits. You might not. Feels free to ask your friends and family for anything they might have. Get something larger than you think, it may help decrease that feeling of claustrophobia when you add layers, plus spray skirt, plus drytop.
Lastly, the hardest part of kayaking and pregnancy is the day you realize you may need to take it easy. As much as we would all love to be paddling until the screaming bundle of goo is born, there might be a day you have to stop. It might be uncomfortable, you might not be able to breath in a seated position for that long, or you might not be able to roll. Don’t forget, safety first.