Acute Fatty Liver of Pregnancy

Acute fatty liver of pregnancy is a disorder limited to the gravid state. It occurs in the third trimester of pregnancy and involves acute hepatic failure. With improved recognition and immediate delivery, the mortality range is now 20-30%. The disorder is usually seen after the 35th week of gestation and is more common in primigravidas and those with twins. The incidence is about 1:14,000 deliveries.

The cause of acute fatty liver of pregnancy is not known. Pathologic findings are unique to the disorder, with fatty engorgement of hepatocytes. Clinical onset is gradual, with flu-like symptoms that progress to the development of abdominal pain, jaundice, encephalopathy, disseminated intravascular coagulation, and death. On examination, the patient shows signs of hepatic failure.

Laboratory findings show marked elevation of alkaline phosphatase but only moderate elevations of ALT and AST. Prothrombin time and bilirubin are also elevated. The white blood cell count is elevated, and the platelet count is depressed. Hypoglycemia may be extreme.

The differential diagnosis is that of fulminant hepatitis. However, liver aminotransferases for fulminant hepatitis are higher (< 1000 units/mL) than those for acute fatty liver of pregnancy (usually < 500 units/mL). It is also important to review the appropriate history and perform the appropriate tests for toxins that cause liver failure. Preeclampsia may involve the liver but typically does not cause jaundice. The elevations in liver function tests in patients with preeclampsia usually do not reach the levels seen in patients with acute fatty liver of pregnancy.

Diagnosis of acute fatty liver of pregnancy mandates immediate delivery. Supportive care during labor includes administration of glucose, platelets, and fresh frozen plasma as needed. Vaginal delivery is preferred. Resolution of encephalopathy occurs over days, and supportive care with a low-protein diet is needed.

Recurrence rates for this liver disorder are unclear. Most authorities advise against subsequent pregnancy, but there have been reported cases of successful outcomes in later pregnancies.

Treem WR: Mitochondrial fatty acid oxidation and acute fatty liver of pregnancy. Semin Gastrointest Dis 2002;13:55.