Exercise is important during pregnancy. Not only does it help prepare your body for labor and delivery, but it also helps you manage the physical changes you'll experience in the coming months.
You should consult your doctor about types and amounts of exercise. In general, it's OK to continue exercises you were frequently doing before pregnancy. But even if you were a daily runner, you may want to select a low-impact activity for the duration of your pregnancy. Walking is an excellent choice, and something you can do up until delivery. Swimming is another option. It works nearly every muscle in the body while allowing you to take advantage of the water's buoyancy.
For dry land workouts, buy a supportive maternity bra. Sure, you may own a drawer full of sports bras, but they're no match for your growing -- and increasingly sensitive -- breasts. A custom fit is key, so take a few measurements before you shop. Place a measuring tape under your arms and around your body to record the band size. Then, place a measuring tape around the fullest part of your bust to record the cup size.