Edema During Late Pregnancy: A Merck Manual of Patient Symptoms podcast

Edema is common during late pregnancy. It typically involves the lower extremities but occasionally appears as swelling or puffiness in the face or hands.

Etiology

The most common cause of edema in pregnancy is

• Physiologic edema

Physiologic edema results from hormone-induced Na retention. Edema may also occur when the enlarged uterus intermittently compresses the inferior vena cava during recumbency, obstructing outflow from both femoral veins.

Pathologic causes of edema are less common but often dangerous. They include deep venous thrombosis (DVT) and preeclampsia (see Table 6: Symptoms During Pregnancy: Some Causes of Edema During Late Pregnancy). DVT is more common during pregnancy because pregnancy is a hypercoagulable state, and women may be less mobile. Preeclampsia results from pregnancy-induced hypertension; however, not all women with preeclampsia develop edema. When extensive, cellulitis, which usually causes focal erythema, may resemble general edema.

Table 6
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Some Causes of Edema During Late Pregnancy Cause Suggestive Findings Diagnostic Approach Physiologic edema Symmetric, bilateral leg edema that lessens with recumbency Diagnosis of exclusion DVT Tender unilateral swelling of a leg or calf, erythema, and warmth Sometimes presence of risk factors for DVT Lower-extremity duplex ultrasonography Preeclampsia Hypertension and proteinuria, with or without significant nondependent edema (eg, in face or hands), which, when present, is not red, warm, or tender Sometimes presence of risk factors for preeclampsia When preeclampsia is severe, possibly additional symptoms of headache; pain in the right upper quadrant, epigastric region, or both; and visual disturbances Possibly papilledema, visual field deficits, and lung crackles (in addition to edema), detected during physical examination BP measurement Urine protein measurement CBC, electrolytes, BUN, glucose, creatinine, liver function tests Cellulitis Tender unilateral swelling in a leg or calf, erythema (asymmetric), warmth, and sometimes fever Manifestations often more circumscribed than in DVT Ultrasonography to rule out DVT unless swelling is clearly localized Examination for source of infection DVT = deep venous thrombosis.

Evaluation

Evaluation aims to exclude DVT and preeclampsia. Physiologic edema is a diagnosis of exclusion.

History: History of present illness should include symptom onset and duration, exacerbating and relieving factors (physiologic edema is reduced by lying in the left lateral decubitus position), and risk factors for DVT and preeclampsia. Risk factors for DVT include

• Venous insufficiency
• Trauma
• Hypercoagulability disorder
• Thrombotic disorders
• Cigarette smoking
• Immobility
• Cancer

Risk factors for preeclampsia include

• Chronic hypertension
• Personal or family history of preeclampsia
• Age < 17 or > 35
• First pregnancy
• Multifetal pregnancy
• Diabetes
• Vascular disorders
• Hydatidiform mole
• Abnormal maternal serum screening results

Review of symptoms should seek symptoms of possible causes, including nausea and vomiting, abdominal pain, and jaundice (preeclampsia); pain, redness, or warmth in an extremity (DVT or cellulitis); dyspnea (pulmonary edema or preeclampsia); sudden increase in weight or edema of the hands and face (preeclampsia); and headache, confusion, mental status changes, blurry vision, or seizures (preeclampsia).

Past medical history should include history of DVT, pulmonary embolism, preeclampsia, and hypertension.

Physical examination: Examination begins with review of vital signs, particularly BP.

Areas of edema are evaluated for distribution (ie, whether bilateral and symmetric or unilateral) and presence of redness, warmth, and tenderness.

General examination focuses on systems that may show findings of preeclampsia. Eye examination includes testing visual fields for deficits, and funduscopic examination should check for papilledema.

Cardiovascular examination includes auscultation of the heart and lungs for evidence of fluid overload (eg, audible S₃ or S₄ heart sounds, tachypnea, rales, crackles) and inspection of neck veins for jugular venous distention. The abdomen should be palpated for tenderness, especially in the epigastric or right upper quadrant region. Neurologic examination should assess mental status for confusion and seek focal neurologic deficits.

Red flags: The following findings are of particular concern:

• BP ≥ 140/90 mm Hg
• Unilateral leg or calf warmth, redness, or tenderness, with or without fever
• Hypertension and any systemic symptoms or signs, particularly mental status changes

Interpretation of findings: Although edema is common during pregnancy, considering and ruling out the most dangerous causes (preeclampsia and DVT) are important:

• If BP is > 140/90 mm Hg, preeclampsia should be considered.
• If edema involves only one leg, particularly when redness, warmth, and tenderness are present, DVT and cellulitis should be considered.
• Bilateral leg edema suggests a physiologic process or preeclampsia as the cause.

Clinical findings help suggest a cause (see Table 6: Symptoms During Pregnancy: Some Causes of Edema During Late Pregnancy). Additional findings may suggest preeclampsia (see Table 7: Symptoms During Pregnancy: Some Findings That Suggest Preeclampsia).

Table 7
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Some Findings That Suggest Preeclampsia System or Body Part Symptom Clinical Finding Eyes Blurry vision Visual field deficits, papilledema Cardiovascular Dyspnea Increased S3 or audible S4 heart sound Tachypnea, rales, crackles GI Nausea, vomiting, jaundice Epigastric or right upper quadrant tenderness GU Decreased urine output Oliguria Neurologic Confusion, headache Abnormal mental status Extremities Weight gain that is sudden and dramatic Edema of legs, face, and hands Skin Rash Petechiae, purpura

Testing: If preeclampsia is suspected, urine protein is measured; hypertension plus proteinuria indicates preeclampsia. Urine dipstick testing is used routinely, but if diagnosis is unclear, urine protein may be measured in a 24-h collection. Many laboratories can more rapidly assess urine protein by measuring and calculating the urine protein:urine creatinine ratio.

If DVT is suspected, lower-extremity duplex ultrasonography is done.

Treatment

Specific causes are treated.

Physiologic edema can be reduced by intermittently lying on the left side (which moves the uterus off the inferior vena cava), by intermittently elevating the lower extremities, and by wearing elastic compression stockings.

Key Points

• Edema is common and usually benign (physiologic) during late pregnancy.
• Physiologic edema is reduced by lying in the left lateral decubitus position, elevating the lower extremities, and using compression stockings.
• Hypertension and proteinuria indicate preeclampsia.
• Unilateral leg edema, redness, warmth, and tenderness require evaluation for DVT.

Last full review/revision August 2009 by R. Phillips Heine, MD; Geeta K. Swamy, MD

Content last modified February 2012