He was my first child. Now he's starting to walk, and I'm finding that I just don't have the energy or the stamina to chase him around. Eating properly for one. I suggest making sure that you are eating enough carbs throughout the day to sustain your energy. Drinking lots of water will also help.
Exercise helps to utilize the glucose that is in the blood stream.
Walking and doing exercises to strengthen the abs, back and upper body are great exercises to do. I also suggest doing flexibility exercises every day. Also, psychologically, I think it's good to have the mindset that she will stay fit while pregnant instead of just letting herself go and get fat. Feel free to send in questions, folks. However, I do know of some relaxation tapes being made to help.