Physiologic Edema: Why Pregnancy Makes You Swollen

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Swelling of your legs, ankles, feet, and fingers is probably part of pregnancy you wish you could do without, but you can’t. This swelling, called physiologic edema, is uncomfortable but normal and important.

During the latter half of pregnancy, and even a bit before then, pregnancy hormones cause you to increase your body fluids and your blood fluids. In fact, your blood and body fluids may increase by 50 percent. This fluid is a big part of your pregnancy weight gain. Fluid in your blood supplies your baby with oxygen and nutrients. Body fluid helps your joints get loose and lubricated, especially your pelvic joints which will need to be supple for delivery.

Some of this extra fluid settles with gravity into the lower parts of your body. You can see it in your ankles, feet and fingers, especially by the end of the day.

Another cause of edema in your lower body is your growing womb. It can press on the blood vessels in your belly and pelvis (pelvic veins) that are returning blood back to your heart. This causes more fluid to leak out into your tissues.

What to Do For Normal Edema of Pregnancy

Normal edema is symmetrical, that means it affects both side of your body about the same. It also decreases when you eliminate the pull of gravity. Swelling is less after lying down. Here are some tips for reducing the discomfort of pregnancy edema:

  • Avoid standing for long periods.
  • Avoid wearing tight shoes and clothing.
  • Get some exercise every day.
  • Take frequent breaks to put your feet up.
  • When resting your legs, do foot exercises like flexing up and down or twirling your feet. This will move blood out of your tissues.
  • When lying down, rest on your left side. This is the best position for taking pressure of your pelvic veins.
  • Drink plenty of water. This will help increase your urine flow and get rid of some extra fluid.
  • Avoid adding salt to your diet. Salt increase fluid retention.

Red Flag Swelling During Pregnancy: Preeclampsia and DVT

Two types of swelling that are also more common during pregnancy are not normal. Both of these are red flags that require immediate medical attention:

  • This condition is pregnancy high blood pressure. It can be dangerous for you and your baby. You may be at risk for preeclampsia if you already have high blood pressure, have a family history of preeclampsia, or have diabetes. This condition causes a sudden increase in edema. You may see swelling in your face and hands. Other warning signs are a severe headache, changes in vision, upper belly pain, or vomiting. If you have these signs, call your doctor right away.
  • DVT is deep vein thrombosis, a blood clot that usually forms in your calf area. Unlike physiologic edema, this swelling is not symmetrical. Along with swelling, you may have redness, tenderness, and warmth. This is a medical emergency because the clot can break loose and travel to your lung, called a pulmonary embolism. Pregnancy increases your body’s blood clotting, so DVT is more common. If you have signs of DVT call your doctor right away or go to the emergency room.

Blood clots are more common during pregnancy because your body is preparing you to stop bleeding after delivery. This is called being in a hypercoagulation state. Signs of a pulmonary embolism are chest pain and difficulty breathing. These signs are always a medical emergency and need a 911 call.

Physiologic edema of pregnancy is a normal part of preparing for birth. Preeclampsia and DVT are rare, but they need to be recognized and treated. Talk to your pregnancy provider about your risks for DVT and preeclampsia. If you have any sudden or painful swelling, let your doctor know.

Christopher Iliades
Dr. Chris Iliades is a medical doctor with 20 years of experience in clinical medicine and clinical research. Chris has been a full time medical writer and journalist since 2004. His byline appears in over 1,000 articles online including EverydayHealth, The Clinical Advisor, and Healthgrades. He has also written for print media including Cruising World Magazine, MD News, and The Johns Hopkins Children's Center Magazine. Chris lives with his wife and close to his three children and four grandchildren in the Boston area.

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