Portal Hypertension and Its Significance in Pregnancy

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Portal hypertension is high blood pressure in within what doctors call the hepatic portal system. This is a system of veins that carries blood to the liver from various sections of the gastrointestinal tract (the stomach and intestines), and from the spleen, the pancreas, and the gallbladder. The pressure in the portal system increases due to what’s called liver cirrhosis. The main causes of liver cirrhosis are alcoholism, hepatitis B virus (HBV), and hepatitis C virus (HCV). In the United States, about 9 of every 1,000 pregnant women harbor the HBV virus, although the numbers vary between different segments of the US population. HBV infection furthermore has been reported in pregnant women at much higher rates in other parts of the world. In some places, the virus is present in 10 percent or more of the population. In such regions, the most important route by which HBV spreads is mother-to-child, also called vertical transmission. While HBV causes portal hypertension by causing cirrhosis, a non-cirrhotic form of portal hypertension (NCPH) also can occur in pregnant women. This can happen due to various, recognized causes, such as infections, and autoimmune diseases, such as systemic lupus erythematosus (SLE, “lupus”). It also can result from toxins affecting the liver and from various processes upstream and downstream from the liver. If no cause can be diagnosed, the condition is called idiopathic non-cirrhotic portal hypertension (INCHP). In fact, 15 percent of people suffering from idiopathic INCPH are females of reproductive age.

Portal hypertension produces particular signs that are noticeable when your doctor performs a physical examination. These signs include ascites (a fluid-filled, distended abdomen), and enlarged, swollen veins (varices) that can be observed on the abdomen or in the anus. Various blood tests and ultrasound images will also be performed. Because, portal hypertension carries a high risk of bleeding from the esophagus, you also need to be evaluated with a procedure called upper endoscopy.

Portal hypertension causes blood to detour through certain groups of veins that normally carry less blood. The extra blood stimulates the development of varices, which are swollen veins. This process can advance more rapidly in pregnancy, because in pregnancy your body produces extra blood. In certain locations, such as the esophagus, varices are prone to severe, life-threatening bleeding. Other dangerous complications of portal hypertension include ascites (fluid fills the abdomen), deterioration of brain function (hepatic encephalopathy), and kidney failure resulting from liver damage (hepatorenal syndrome). Portal hypertension also elevates the risk for spontaneous abortion (miscarriage), stillbirth, and preterm and premature mature birth. These outcomes are particularly likely if you suffer from variceal bleeding.

Your doctors may decide to lower your risk of variceal bleeding by lowering your blood pressure with a beta-blocker medication, and possibly a diuretic (drug that promotes excretion of water through the kidney). Beta-blocker treatment carries a risk of fetal growth restriction and slowing down the fetal heartbeat. However, the fetal risks must be weighed against the risk of the mother suffering a life-threatening bleed. Another medication given for lowering portal pressure is isosorbide, but more study is required of this drug in pregnancy settings. Particularly if you suffer from a swollen abdomen, a diuretic will be a likely part of the treatment and your doctors are likely to put you on an antibiotic, because ascites carries a risk of a dangerous complication called peritonitis. Generally, the antibiotic given will be one that is considered safe, not only in pregnancy, but also in nursing mothers.

Common treatments for portal hypertension also include sclerotherapy and banding, both of which are performed by way of endoscopy (a tube is inserted through the gastrointestinal tract and instruments and a camera are passed through the tube). This is for the purpose of preventing varices from bleeding. Surgical treatments are available to shunt blood away from the portal system in order to lower the pressure. A large component of the management consists of supportive measures, such as administration of fluids and monitoring of your liver function. If you are progressing toward liver failure, it may become necessary to terminate the pregnancy in order to save your life. In the case of liver failure, the only curative treatment is liver transplantation.

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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