Well you can't really do any strenuous workouts while carrying a little one, but what you SHOULD be focused on, is being healthy. MUSTS are milk, fruits, and veggies. Vitamins are pretty important too, especially if you're like me and despise milk! If you DON'T get the appropriate amount of milk, it can cause you to have defeciencies which could weaken your bones and your teeth. When I was pregnant, I even stopped eating meat for the most part. I ate a lot of salt fee nuts though, to make up for the protein that I was missing. I usually ate a bowl of cereal for breakfast every day....and some may say (including my parents) that it wasn't healthy, but I am not talking about lucky charms. Special K or Banana Nut Crunch are good. Or Grape Nuts with a banana sliced on top. There are a lot of vitamins in GOOD cereals, and you also get the milk. I had a big ole bowl of fruit for lunch, and usually nothing but veggies for dinner. BTW! STOP WITH THE COFFE AND CARBONATED DRINKS!! TOO MUCH SUGAR AND CAFFIENE!
Also, DO NOT use pregnancy as an excuse to be lazy. I worked full time, in a restaurant, walking for 6 or more hours a shift, throughout my entire pregnancy. Yes, I was tired some days, and yes I felt pretty crappy, but the people that give in to those feelings are the ones that become unhealthy. Walk, walk, and walk. You're going to gain weight, you're ankles will likely still swell from water retintion, you'll still likely have nausea, and you will still be cranky. BUT you'll look great, feel great (for being pregnant), labor will be a breeze compared to if you HADN'T kept in shape, and afterwards, when you're holding that beautiful baby, you won't give a d*mn what you look like! (But when you DO get to a mirror, you'll think you look d*mn good for having just given birth!)