Pregnancy normally has minimal effect on liver function tests, including most liver enzyme levels. Thus, when liver enzymes are elevated during pregnancy, it usually indicates a liver disorder. According to a July 2013 review in the "International Journal of Critical Illness and Injury Science," liver disease complicates up to 3 percent of pregnancies. Some of these diseases occur only with pregnancy -- hyperemesis gravidarum, intrahepatic cholestasis of pregnancy, acute fatty liver of pregnancy, preeclampsia and HELLP syndrome. Other disorders can occur in anyone but may be more common or more severe in pregnancy. Furthermore, some women will have liver disease that began before they became pregnant.
Milder Disorders of Pregnancy
Hyperemesis gravidarum is unrelenting nausea and vomiting in pregnancy, which usually occurs between the 4th and 10th week of pregnancy and resolves by the 20th week. It can result in dehydration, weight loss and hospitalization. According to a November 2013 article in "World Journal of Gastroenterology," about 1 in 200 women develop hyperemesis gravidarum and approximately 50 percent of those requiring hospitalization have elevated liver enzymes. Intrahepatic cholestasis of pregnancy is a disorder that results in impaired excretion of bile acids in the liver and elevated liver enzymes. Itching, particularly of the palms and soles, is a prominent symptom. It usually occurs in the 2nd half of pregnancy and typically resolves soon after the baby is born.
Severe Disorders of Pregnancy
Preeclampsia is a disorder of pregnancy characterized by high blood pressure, swelling and protein in the urine. The cause is uncertain but appears to be related to abnormal function of the endothelium -- cells lining blood vessels and the surfaces of body organs. HELLP syndrome is a severe form of preeclampsia characterized by Hemolysis, Elevated Liver enzymes and Low Platelets. Hemolysis is the destruction of red blood cells and platelets are the blood cells responsible for forming blood clots. Acute fatty liver of pregnancy, or AFLP, also causes elevated liver enzymes. It is rare but occurs when fat accumulates in the liver. Both HELLP syndrome and AFLP usually occur after the 27th week of pregnancy. They require urgent delivery of the baby.
Conditions Affected by Pregnancy
Changes in hormone levels and gallbladder function during pregnancy increase the risk of developing gallstones. Symptoms are similar for pregnant and nonpregnant women and can include right-sided abdominal pain, nausea, vomiting and fever. Abnormal lab tests typically include elevated liver enzymes, and surgery may be necessary for severe symptoms. Pregnant women may also develop viral hepatitis. Their risk of developing these infections is not increased by pregnancy and the symptoms and severity of most types of viral hepatitis are similar whether or not they occur in pregnancy. Hepatitis due to hepatitis E and herpes simplex viruses, however, are exceptions. They can be significantly more severe when they occur during pregnancy.
Pre-existing Liver Disease
Pregnancy may occur in women who already have liver disease. In most instances, the presence of these conditions will be known and the woman will already be receiving medical care for them. Cirrhosis of the liver is the result of chronic liver damage and scarring, usually from alcohol or viral hepatitis B or C. Autoimmune liver disease is another possible cause of cirrhosis, and pregnancy can aggravate the liver destruction caused by this disorder. Wilson disease and Budd-Chiari syndrome are rare causes of liver disease that can cause elevated liver enzymes in pregnancy. Wilson disease leads to abnormal deposits of copper in the body, and Budd-Chiari syndrome occurs when there is a blockage of the hepatic vein.