Edema (Swelling) During Pregnancy: How Is It Managed?

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Edema is the medical word for swelling, a phenomenon resulting from the accumulation and retention of fluid in body tissues. In can happen at different sites within the body. Fluid in the lungs, for instance, is pulmonary edema. Fluid in the brain is cerebral edema. Such conditions are dangerous, but during pregnancy, edema tends to occur mainly in the lower extremities, notably the the ankles and calves. This is not particularly dangerous, but it can be uncomfortable. While there have not been a large number of studies on the prevalence of this condition during pregnancy, studies that have been conducted have suggested that as many as 67 percent of pregnant women suffer edema, mostly in the lower legs. Edema may also occur in face, in which case it can be a sign of a pregnancy complication called preeclampsia. A complex condition involving fluids, blood pressure, and problems with at least one organ, usually the kidneys, preeclampsia strikes 2 to 8 percent of pregnancies. Additionally, edema also can be a sign of another pregnancy complication called HELLP syndrome, which develops in up to 0.9 percent of pregnancies and in 25 percent of women with preeclampsia. Pulmonary edema (edema in the lungs) meanwhile has been reported to affect 0.08 percent to 1.5 percent of pregnancies. In such cases, the pulmonary edema can develop in the setting of preeclampsia or HELLP, or it can develop separately, due to medications given to delay labor, sometimes due to excessive fluid administration, or otherwise due to underlying heart disease that pregnancy exacerbates.

To diagnose edema of the limbs or the face, the doctor can simply perform a physical examination. To diagnose pulmonary edema, usually this starts with a high level of suspicion for the presence of pulmonary edema based on the presence of symptoms and signs. These include dyspnea (breathing difficulty), wheezing, coughing with pink, frothy sputum, cyanosis (bluish skin), a rapid heartbeat with palpitations, cold and clammy skin, and oxygen saturation (SpO2) that is below the normal cutoff of 95 percent at sea level (the lower limit for normal is less at higher elevations). Diagnosis can then be confirmed by way of a chest X-ray. It is also possible to diagnose pulmonary edema by way of computed tomography (CT) scanning, but this usually is not necessary and it exposes the fetus to more radiation than a simple chest X-ray, so CT is usually avoided in this setting. The radiation dose from a simple chest X-ray is too small to be harmful to the fetus, so it need not be avoided during pregnancy. HELLP stands for hemolysis, elevated liver enzymes, and low platelets, all of which can be detected through various laboratory tests. Preeclampsia is diagnosed by way of laboratory tests on blood and urine, along with measurements of your blood pressure.

Most edema in pregnancy is limited to the lower extremities. As noted earlier, this can be very uncomfortable, but usually does not cause life-threatening problems. Leg edema is worse in hot weather and after you have been standing for a long time. Swelling in the legs also could be a sign of a deep venous thrombosis (DVT, a clot in the vein), which can be dangerous. Thus, you must be checked by your doctor. The other complications connected with edema that are discussed above are potentially life threatening, so they must be evaluated and managed by your doctors. Swelling in your legs during pregnancy in the absence of a DVT and without other problems is not dangerous to the fetus. On the other hand, preeclampsia, HELLP syndrome, and pulmonary edema threaten the life of both the mother and fetus. With pregnancy complications as serious as preeclampsia and HELLP syndrome, the solution generally is to deliver the baby as early as possible, a situation that increases the chances that the baby will suffer behavioral, emotional, and learning difficulties.

Normally, edema can be treated with medicines called diuretics. These include furosemide, but some controversy surrounds their use during pregnancy. According to the US Food and Drug Administration, diuretics should be administered in pregnancy, only when the benefits outweigh the risks, such as in settings of pulmonary edema and preeclampsia. This means that there’s no justification for using them to treat edema of the legs. Meanwhile, extreme caution is advised when furosemide is administered to mothers who wish to nurse, because this medication may inhibit production of breast milk, and also may enter breast milk.

If your pregnancy edema is limited to the legs, you are not likely to need any medication, but there are things that you can do to improve your condition. Classically, people have been advised to reduce their intake of salt, although lately there has been some controversy about the value of such measures. Something that definitely helps, however, is to avoid long periods of standing or sitting. If you must sit for a long time, keeping your legs up, resting on a cushion, can help. Additionally, you will find it helpful to wear comfortable shoes and engage in exercise that is appropriate for your stage of pregnancy.

David Warmflash
Dr. David Warmflash is a science communicator and physician with a research background in astrobiology and space medicine. He has completed research fellowships at NASA Johnson Space Center, the University of Pennsylvania, and Brandeis University. Since 2002, he has been collaborating with The Planetary Society on experiments helping us to understand the effects of deep space radiation on life forms, and since 2011 has worked nearly full time in medical writing and science journalism. His focus area includes the emergence of new biotechnologies and their impact on biomedicine, public health, and society.

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