Out of all the pregnancy gripes that expecting moms commonly experience, back pain probably tops the list. "It's often caused by a shifting of the center of gravity, and by the weight of the uterus on the pelvic area," says Thomas Hanlon, author of Fit For Two.

By stretching your back daily and doing muscle-strengthening exercises, you can help minimize or avoid back pain altogether -- during pregnancy and beyond. Always check with your physician before beginning a new exercise program. And if you ever feel discomfort while doing the exercises, stop immediately.

The Warm-up

Walk or jog in place for five minutes to warm up. You can do the stretches every day, but give your muscles 48 hours of rest in between the strength-training moves that involve weights.

Cat Back Stretch

(to stretch your entire back)

Get down on all fours and flatten your back so your spine is aligned from your neck to your tailbone. Now, arch your back slowly, starting at the tailbone and stretching up through your shoulder blades. Hold for 5 seconds. Relax to the neutral starting position. Repeat 5 times.

Heel Sits

(to stretch your lower back and buttocks)

Get down on your knees and bend over, stretching your hands out before you, palms flat on the floor. Slowly rock back onto your heels; as your baby grows, move your knees wider apart to accommodate your tummy. While sitting back, walk your fingers forward, increasing the stretch. Stretch one arm at a time for increased flexibility. Hold for 20-30 seconds; repeat 2-3 times.

Arm Raises

(to strengthen shoulders and upper back)

Get down on all fours, making sure your back is flat (as in the Cat Stretch described above). Raise your right arm straight out in front of you to shoulder level. Hold for 5 seconds. Lower and repeat 10 times. Switch arms and repeat. When this becomes easy, add a second set. Holding a 1- or 2-pound dumbbell or wearing wrist weights will make the exercise even more challenging.

Overhead Pull-Down

(to strengthen your middle and lower back)

Stand with your knees relaxed and extend your arms up and over your head. Imagine that you're holding a barbell in your hands. Now pull your arms down, bending your elbows out to the sides until your hands are shoulder height. The "bar" should be behind your head. Return to the starting position. Repeat 10-15 times, and complete 3 sets. When this becomes easy, hold a 1- or 2- dumbbell in each hand.

Upright Row

(to strengthen your shoulder and upper back muscles)

Stand with your feet shoulder-width apart and your knees relaxed. Let your arms relax at your sides, palms facing back. Now pull your elbows up and back until they are at shoulder height. Contract your muscles in order to resist the movement. Now lower to the starting position. Repeat 10-15 times. Complete 3 sets. When this become easy, hold a 1- or 2- dumbbell in each hand.