Fluid buildup in the abdomen

Last medical review:

Fluid buildup in the abdomen is called ascites.

Ascites happens in the peritoneal cavity when the body makes more fluid than it can remove. It can happen because of cancer and other conditions. When ascites is due to cancer, or if the fluid in the abdomen has cancer cells, it is often called malignant ascites or malignant peritoneal effusion.

Ascites develops most often with ovarian, uterine, cervical, colorectal, stomach, pancreatic, breast and liver cancers. Cancer that spreads to the liver can also cause ascites.


Ascites can be caused by:

  • cancer cells that spread to and irritate the thin lining of the inner wall of the abdomen (called the peritoneum)
  • tumours that block the lymphatic system so that lymph fluid can't flow properly
  • the liver not making enough protein (albumin), which may disturb the body's fluid balance
  • cancer cells that block blood flow through the liver


Symptoms of ascites can vary depending on their cause and other factors. They include:

  • swelling of the abdomen
  • bloating
  • pain in the back or abdomen
  • fatigue
  • shortness of breath
  • weight gain
  • nausea
  • vomiting
  • indigestion
  • loss of appetite
  • feeling full after eating a small amount
  • constipation
  • swelling of the ankle or leg
  • changes to the belly button

If symptoms get worse or don't go away, tell your doctor or healthcare team as soon as possible without waiting for your next scheduled appointment.


Your doctor will try to find the cause of ascites. You may need to have the following tests:

  • a physical exam
  • an abdominal x-ray
  • an abdominal ultrasound or a CT scan

Sometimes fluid is removed from the abdomen to see if it contains cancer cells.

Managing ascites

Once the cause of ascites is known, your healthcare team can suggest ways to manage it, such as:

  • reducing the amount of salt you eat and the amount of fluids you drink
  • taking medicines to help your body get rid of extra fluids (called diuretics)
  • removing fluid from the abdomen with a long, hollow needle (called a paracentesis)
  • infusing albumin into the abdomen after a paracentesis to help slow down the buildup of fluid
  • inserting a catheter into the abdomen to remove fluid on a regular basis

Chemotherapy or radiation therapy can be used to treat the cancer that is causing the ascites. You may also be offered surgery to redirect fluid from one place to another so that it doesn't build up (called a shunt).

Expert review and references

  • Valerie Fiset, RN, MScN

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