As your pregnancy progresses, your body increases its overall fluid volume by 50 percent. This extra fluid, plus hormonal changes and increased weight, mean swollen feet and ankles, especially in the third trimester. Exercise is one strategy to relieve swelling and prevent its return.
Swollen feet, legs and ankles happen because fluid becomes trapped inside your tissues on its way back to your heart. Walking helps relieve this fluid congestion in two ways. First, the pumping and contracting of your leg muscles helps squeeze water out of your tissues. Second, the increased circulation caused by your elevated heart rate helps flush that fluid away. Walking too much can make swelling worse, so aim for 20 to 30 minutes each day.
Water aerobics, or any deep-water exercise such as swimming or water walking, can help reduce pregnancy edema, according to a 2000 study in "American Family Physician." Kicking and working your muscles in the pool reduces fluid much like waking. Water pressure against your soft tissues gently squeezes and works to force out additional fluid. Many pregnant women find relief from sore, tired, swollen limbs in the semi-weightless environment water provides.
Sitting or lying in one position for too long can make edema worse. If you work at a desk or if you're on light duty or bed rest, ankle pumps can help keep your muscles pumping and your blood flowing enough to reduce swelling. To do them, flex your feet at the ankles. First point your toes away from you as far as you can, then point them toward you as much as you can. Do ankle pumps for a few minutes every one to two hours.
Prenatal yoga helps improve circulation. It also strengthens leg muscles, which are then more effectively able to push fluid out of your extremities when you move them. Some yoga positions place your feet in an elevated position, so they're above the heart. Elevating your feet helps reduce swelling, but women should only lie on their backs for one to three minutes in the second trimester and none at all in the third trimester. Lying on your back can cause your uterus to press against one of your body's major arteries, limiting blood flow.