Various factors contribute to foot and ankle swelling during pregnancy. For starters, your body retains more fluid during pregnancy. Also, your growing uterus puts pressure on your veins, which impairs return of blood to your heart. Hormonal changes also play a role.

Foot and ankle swelling during pregnancy is common and usually goes away after delivery. In the meantime, it might help to:

• Stay off your feet. Avoid standing for long periods. When you can, sit with your feet up and occasionally rotate your feet at the ankles and gently flex your feet to stretch your calf muscles. Better yet, lie down with your legs elevated.
• Sleep on your left side. This takes pressure off the large vein that returns blood from the lower half of your body to your heart (inferior vena cava). It also might help if you elevate your legs slightly with pillows.
• Wear compression stockings. Your health care provider might recommend wearing supportive tights or stockings during the day.
• Be physically active every day. Take walks, ride a stationary bike or swim laps in a pool.
• Stand or walk in the pool. Although there's little research on the use of water pressure for foot and ankle swelling, standing or walking in a pool seems to help compress tissues in the legs and might provide temporary relief from swelling during pregnancy.
• Wear loose clothing. Tight clothing can restrict blood flow. Don't wear socks or stockings with tight bands on the ankles or calves.

Some research suggests that foot massage and reflexology, which involves applying pressure to certain areas of the feet, hands and ears, might help decrease foot and ankle swelling during pregnancy. Also, swelling doesn't mean cutting back on how much you drink. The Institute of Medicine recommends about 10 cups (2.4 liters) of fluids a day during pregnancy.

Although mild foot and ankle swelling during pregnancy is normal, sudden swelling that is painful — especially if it's in one leg only — could be an indication of a blood clot (deep vein thrombosis). A sudden increase in swelling also might mean that your blood pressure is higher than normal. Both conditions require prompt evaluation and treatment.