Edema in pregnancy is swelling caused by extra fluid collecting in your body’s tissues, most commonly in the feet, ankles, and lower legs. It affects roughly two-thirds of pregnant women and is usually a normal part of pregnancy rather than a sign of something wrong. The swelling tends to appear in the second half of pregnancy and peaks during the final two months.
Why Pregnancy Causes Swelling
During a normal pregnancy, your blood volume increases by nearly two liters. That extra fluid is necessary to support the placenta and your growing baby, but some of it inevitably leaks from blood vessels into surrounding tissues. At the same time, hormonal shifts make blood vessel walls more permeable, allowing even more fluid to pass through.
The growing uterus also plays a mechanical role. As it gets larger, it presses on the inferior vena cava, the large vein that returns blood from your lower body to your heart. This pressure slows blood flow from your legs and pelvis, causing fluid to pool in your feet and ankles. Gravity makes things worse, which is why swelling tends to be most noticeable at the end of the day or after long periods of standing.
When Swelling Typically Starts
Most pregnancy-related leg edema shows up in the third trimester, particularly during months eight and nine. The earliest it tends to appear is around 24 weeks of gestation. Before that point, your uterus isn’t large enough to put significant pressure on your pelvic veins, and the blood volume expansion hasn’t yet peaked.
The swelling often fluctuates day to day. Hot weather, salty meals, and prolonged standing can all make a given day worse. You may notice your shoes feel tight by evening but fit normally again in the morning after lying flat overnight.
Normal Swelling vs. Warning Signs
Mild, symmetrical swelling in both legs that comes and goes is almost always harmless. But sudden or severe swelling, especially in the face and hands, can signal preeclampsia, a serious condition defined by high blood pressure (above 140/90 mmHg) and signs of organ stress such as protein in the urine.
Preeclampsia develops in the second half of pregnancy and isn’t always obvious at first. In one form of the condition, lower-leg edema gradually progresses to generalized swelling throughout the body, accompanied by rising blood pressure. In another form, swelling appears later as the condition worsens and begins affecting organs like the kidneys and liver.
Watch for these alongside worsening swelling:
- Sudden weight gain over a few days, suggesting rapid fluid retention
- Swelling in your face or around your eyes, especially in the morning
- Persistent headaches or visual changes like blurred vision or seeing spots
- Pain in the upper right abdomen, beneath the ribs
Swelling in only one leg, particularly if it’s red, warm, or painful, is a different concern. This pattern can indicate a blood clot (deep vein thrombosis), which pregnancy increases the risk for. One-sided swelling deserves prompt medical evaluation.
Practical Ways to Reduce Swelling
You won’t eliminate edema entirely while pregnant, but you can keep it manageable. The strategies below target the underlying causes: improving blood return from the legs, reducing fluid leakage, and helping your kidneys clear excess fluid.
Positioning and Movement
Elevate your legs above heart level for 15 to 20 minutes several times a day. Use pillows or a cushion to prop your feet up while reading or watching TV. This lets gravity work in your favor, draining pooled fluid back toward your core. At night, sleeping on your left side shifts the uterus off the inferior vena cava and improves venous return from the legs. Either side is safe, but the left is generally preferred for circulation.
Avoid sitting or standing in one position for long stretches. Even brief walks or ankle circles while seated help activate the calf muscles that pump blood upward.
Compression Socks
Knee-high compression socks rated at 15 to 20 mmHg provide gentle, steady pressure that helps prevent fluid from settling in your lower legs. They’re most effective when you put them on in the morning before swelling builds up. Look for graduated compression styles, which are tighter at the ankle and looser toward the knee.
Hydration and Sodium
Drinking plenty of water sounds counterintuitive when you’re already retaining fluid, but staying well hydrated helps your kidneys flush excess sodium and keeps fluid circulating rather than pooling. Water is the best choice.
Cutting back on sodium makes a noticeable difference for many women. Prepackaged foods, canned soups, chips, and deli meats are some of the biggest sources of hidden salt. Cooking from whole ingredients gives you more control over how much sodium you’re actually consuming.
Footwear and Cool Water Soaks
The American College of Obstetricians and Gynecologists recommends shoes with a low heel (not flat) and good arch support, like athletic shoes. Tight shoes or high heels restrict circulation and worsen discomfort. Immersing your feet and ankles in cool (not ice-cold) water for about 20 minutes a few times a week can also reduce swelling temporarily. Loose clothing that doesn’t constrict the waist or legs helps blood flow freely.
How Quickly Swelling Goes Away After Delivery
Once the baby is born and the uterus shrinks, the mechanical pressure on your veins disappears quickly. Your body also begins shedding the extra fluid it accumulated, largely through increased urination and sweating in the first few days postpartum. Most women notice significant improvement within a week of delivery, though in some cases residual swelling takes up to two weeks to fully resolve.
Postpartum swelling can actually get temporarily worse in the first two or three days, especially if you received IV fluids during labor. This is normal and resolves on its own. The same strategies that helped during pregnancy, like elevation, compression socks, and staying hydrated, work equally well during recovery.