Acute fatty liver of pregnancy

Definition

• Acute fatty liver of pregnancy is a rare, life-threatening complication of late pregnancy with acute liver dysfunction due to microvesicular fatty infiltration of the liver parenchyma, which can lead to coagulopathy, electrolyte imbalance and multi-organ failure.

Occurrence & epidemiology

Epidemiology

• The incidence is about 1 in 7,000 to 1 in 20,000 pregnancies; it recurs in a later pregnancy in about 20%.

Aetiopathogenesis

Aetiology and risk factors

• The cause is mitochondrial dysfunction and defects of fetal and placental fatty acid oxidation, especially fetal LCHAD deficiency; toxic 3-hydroxy fatty acids reach the maternal circulation and cause microvesicular fatty liver.
• Primiparous women, pregnancies with a male fetus, multiple pregnancies, women with previous acute fatty liver of pregnancy and low BMI are more often affected; pre-eclampsia coexists in more than 50%.

Clinical features

Clinical features and complications

• It occurs in the third trimester, rarely late in the second trimester or shortly after birth; initially there is non-specific epigastric pain, nausea and vomiting with raised transaminases.
• Early complications are hypoglycaemia, acute pancreatitis, infection and acute renal failure; signs of acute liver failure such as encephalopathy and bleeding from coagulopathy usually follow 1–2 weeks after onset, together with disseminated intravascular coagulation and postpartum haemorrhage.

Histology

• Liver biopsy typically shows microvesicular fatty infiltration of hepatocytes; it is not required for the diagnosis and is rarely performed in pregnancy.

Diagnosis

• Laboratory findings include moderately raised transaminases that do not correlate with severity; leucocytosis and raised urea and creatinine are common, followed by hypoglycaemia and raised ammonia; platelets are usually normal unless DIC is present.
• The Swansea criteria standardise the diagnosis: at least 6 of 14 points from clinical and laboratory findings such as nausea or vomiting, abdominal pain, encephalopathy, raised bilirubin, leucocytosis, raised transaminases and creatinine, prolonged PT/aPTT and steatosis on ultrasound support the diagnosis.
• Imaging contributes little to the diagnosis and mainly serves to exclude other liver processes such as haematoma or rupture.

Keep learning in the app

Further reading (selection)

1. StatPearls: Acute Fatty Liver of Pregnancy (NCBI Bookshelf)
2. Int J Mol Sci 2022: Mitochondrial Dysfunction and Acute Fatty Liver of Pregnancy (PMC, open access)

Cross-references