As pregnancy progresses, fluid may accumulate in tissues, usually in the feet, ankles, and legs, causing them to swell and appear puffy. This condition is called edema. Occasionally, the face and hands also swell. Some fluid accumulation during pregnancy is normal, particularly during the 3rd trimester. It is called physiologic edema.
Fluid accumulates during pregnancy because the adrenal glands produce more of the hormones that make the body retain fluids [aldosterone and cortisol]. Fluid also accumulates because the enlarging uterus interferes with blood flow from the legs to the heart. As a result, fluid backs up in the veins of the legs and seeps out into the surrounding tissues.
Usually during pregnancy, swelling is
Physiologic edema
In preeclampsia, blood pressure and protein levels in urine increase during pregnancy. Fluids may accumulate, causing swelling in the face, hands, or feet and weight gain. If severe, preeclampsia can damage organs, such as the brain, kidneys, lungs, or liver, and cause problems in the baby.
Peripartum cardiomyopathy causes shortness of breath and fatigue as well as swelling.
In cellulitis, bacteria infect the skin and tissues under the skin, sometimes causing swelling with redness and tenderness. Cellulitis most commonly affects the legs but may occur anywhere.
The risk of deep vein thrombosis and preeclampsia is increased by various conditions [risk factors].
For deep vein thrombosis, risk factors include the following:
A previous episode of deep vein thrombosis
Inherited blood clotting disorders
A disorder that makes blood more likely to clot, such as cancer or kidney or heart problems
Immobility, as may occur after an illness or surgery
Obesity
For preeclampsia, risk factors include
Preeclampsia during a previous pregnancy or a family member who has had preeclampsia
Age under 17 or over 35
A first pregnancy
A pregnancy with more than one fetus
Blood vessel [vascular] disorders
For peripartum cardiomyopathy, risk factors include the following:
Age 30 or older
African descent
A pregnancy with more than one fetus
Preeclampsia
Doctors must rule out deep vein thrombosis, preeclampsia, a heart disorder, cellulitis, and other possible causes before they can diagnose physiologic edema.
In pregnant women with swollen legs, the following symptoms are cause for concern:
Blood pressure that is 140/90 mm Hg or higher
Swelling in only one leg or calf, particularly if the area is warm, red, and/or tender or fever is present
Swelling in the hands
Swelling that suddenly increases
Confusion, difficulty breathing, changes in vision, shaking [tremor], a seizure, sudden abdominal pain, or a sudden headache—symptoms that may be caused by preeclampsia
Chest pain
Women should go to the hospital immediately if they have
Symptoms that suggest preeclampsia or a heart disorder
Women with other warning signs should see a doctor that day. Women without warning signs should see a doctor, but a delay of several days is usually not harmful.
Doctors ask the following:
When the swelling started
How long it has been present
Whether any activity [such as lying on the left side] lessens or worsens it
Lying on the left side decreases physiologic edema.
Doctors also ask about conditions that increase the risk of developing deep vein thrombosis, preeclampsia, and peripartum cardiomyopathy.
Women are asked about other symptoms, which may suggest a cause. They are asked whether they have ever had deep vein thrombosis, pulmonary embolism, preeclampsia, high blood pressure, or heart problems, including cardiomyopathy.
During the physical examination, doctors look for evidence of a serious cause. To check for symptoms of preeclampsia, doctors measure blood pressure, listen to the heart and lungs, and may check the woman's reflexes and look at the back of her eyes with an ophthalmoscope [a handheld device that resembles a small flashlight]. Doctors also look for areas of swelling, particularly in the legs, hands, and face. Any swollen areas are checked to see if they are red, warm, or tender.
If deep vein thrombosis is suspected, Doppler ultrasonography of the affected leg is done. This test can show disturbances in blood flow caused by blood clots in the leg veins.
If preeclampsia is suspected, the protein level is measured in a urine sample. High blood pressure plus a high protein level in urine indicates preeclampsia. If the diagnosis is unclear, the woman is asked to collect her urine for 24 hours, and protein is measured in that volume of urine. This measurement is more accurate. However, preeclampsia may also be present if the protein level in urine is normal. High blood pressure with headache, changes in vision, abdominal pain, or abnormal blood or urine test results may also indicate preeclampsia.
If peripartum cardiomyopathy is suspected, electrocardiography, chest x-ray, echocardiography, and blood tests to check heart function are done.
When swelling results from a disorder, that disorder is treated.
The swelling that occurs normally during pregnancy can be reduced by doing the following:
Lying on the left side, which moves the uterus off the large vein that returns blood to the heart [inferior vena cava]
Resting frequently with the legs elevated
Wearing elastic support stockings
Wearing loose clothing that does not restrict blood flow, particularly in the legs [for example, not wearing socks or stockings that have tight bands around the ankles or calves]
Some swelling in the legs and ankles is normal [physiologic] during pregnancy and occurs during the 3rd trimester.
Doctors can identify serious causes of swelling based on results of a physical examination, blood pressure measurement, blood and urine tests, and sometimes ultrasonography.
If pregnancy itself is the cause, swelling can be reduced by lying on the left side, elevating the legs periodically, wearing support stockings, and wearing clothing that does not restrict blood flow.