Me on my due date, about to hit the gym
I kept up with my workout regimen from the second trimester, with some minor modifications. I continued to walk on the treadmill whenever I could at work, usually 2-3 times a week for 30-60 minutes, and stuck with incline walking at the gym for my cardio of choice. I continued to lift weights, and always aimed for three days (back & bicep, legs, and chest, shoulders and triceps), but often ended up doing two days (one upper body, one lower body). I was also religious about doing my prenatal yoga and Pilates every night before bed. I did the 15 minute yoga sequence and about 10-15 minutes of Pilates. I started doing less ab work at the gym, and started doing more kegels and belly breathing, rather than things like planks or oblique twists.
I found I was able to keep the weights for upper body strength training the same as I had in the second trimester (which was slightly lower than I did in the first trimester), but my lower body actually was becoming stronger. I suppose with the 20-25 extra pounds I was carrying around in this trimester, my legs were building up strength, even though I wasn't working out as intensely as I was before being pregnant.
I really expected pregnancy to make me feel weak and tired all the time, and there were definitely those days, but overall, I felt amazing. I felt strong, comfortable, and often times felt I could have pushed myself more, but knew I had to be careful. Looking back now almost a year later, there's not anything I would have done differently throughout my pregnancy. I put a lot of work into making sure I was active and ate well for those 41 weeks. I have no doubt it helped me bounce back quickly after baby was born, and played a very important part in how healthy Harper was when she arrived.