Acute fatty liver of pregnancy !

A rare, dangerous liver failure in late pregnancy: fat builds up inside the liver cells. The mother needs urgent delivery and intensive care.

Updated 2026-11-01

Structures involved

Tap one to see what it is and open it in 3D.

Why it happens

What it is

A rare obstetric emergency of the third trimester (or early postpartum) in which microvesicular fat accumulates in hepatocytes, leading to acute liver failure with hypoglycaemia, coagulopathy and kidney injury. Delivery is the only definitive treatment.

Who gets it

Rare: about 1 in 7,000 to 1 in 20,000 pregnancies, usually around 35–37 weeks. More frequent with twin pregnancies and male fetuses. Maternal and fetal mortality have fallen with early recognition and delivery but remain significant, including in Latin American referral centres.

Causes

Fetal deficiency of long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) or other fatty acid oxidation defects in some cases
Fetal and placental fatty acid metabolites enter the maternal circulation and overload the maternal liver
Late-pregnancy changes in maternal fat metabolism

Risk factors

Fetal fatty acid oxidation disorder (LCHAD deficiency)
Multiple pregnancy
Male fetus
First pregnancy
Low maternal body mass index
Preeclampsia or HELLP syndrome in the same pregnancy
Previous acute fatty liver of pregnancy

Pathophysiology

When the fetus cannot oxidise long-chain fatty acids, toxic intermediates cross back to the mother. Combined with the mother’s own reduced mitochondrial capacity in late pregnancy, fat accumulates as tiny droplets in hepatocytes (microvesicular steatosis) and mitochondrial function fails. The liver can no longer make glucose, clotting factors or clear ammonia, so hypoglycaemia, coagulopathy and encephalopathy follow, often with acute kidney injury and pancreatitis.

Classification

Swansea criteria (6 or more of 14 clinical, laboratory and imaging or biopsy features, in the absence of another cause) are widely used to support the diagnosis

Symptoms and signs

Malaise, loss of appetite, nausea and vomiting
Right upper quadrant or epigastric pain
Jaundice
Excessive thirst and passing large amounts of urine (transient diabetes insipidus)
Confusion, drowsiness (encephalopathy)
Bleeding from coagulopathy
Mild hypertension and proteinuria in about half of cases

Diagnosis

Clinical: Suspected in a woman in the third trimester with vomiting, abdominal pain, jaundice or malaise and signs of liver failure; supported by the Swansea criteria after excluding other causes.
Tests: Raised bilirubin and transaminases (usually moderately), hypoglycaemia, raised ammonia and uric acid, raised creatinine, leucocytosis, prolonged prothrombin time and low fibrinogen and antithrombin. Glucose must be checked frequently. Liver biopsy is diagnostic but rarely done because of coagulopathy.
Imaging: Ultrasound may show a bright (echogenic) liver or ascites but is often normal; CT or ultrasound mainly exclude other causes. A normal scan does not rule the condition out.

Differential diagnosis

HELLP syndrome and severe preeclampsia
Acute viral hepatitis
Drug-induced liver injury
Intrahepatic cholestasis of pregnancy
Thrombotic microangiopathies
Hyperemesis gravidarum with liver test abnormalities

Goal of treatment

Stabilise the mother and deliver the baby promptly, then support the liver and other organs in intensive care until hepatic function recovers.

Treatment

Acute: Stabilisation: correct hypoglycaemia with intravenous glucose, correct coagulopathy with plasma, cryoprecipitate and platelets, and control blood pressure.
Surgical: Prompt delivery once the mother is stabilised, by induction or caesarean section according to obstetric and maternal condition; anaesthesia is planned around the coagulopathy.
Follow-up: Intensive care with frequent glucose checks, coagulation studies, renal function, fluid balance and neurological observation; nursing priorities are hypoglycaemia detection and bleeding precautions.
Acute: Organ support as needed: management of encephalopathy, renal replacement therapy, plasma exchange in selected cases and referral for liver transplant evaluation if the liver fails to recover.
Follow-up: The newborn should be tested for fatty acid oxidation disorders, and the parents offered genetic counselling.

Complications

Acute liver failure and hepatic encephalopathy
Disseminated intravascular coagulation and postpartum haemorrhage
Acute kidney injury
Severe hypoglycaemia
Acute pancreatitis
Maternal death
Fetal death or neonatal metabolic crisis from an inherited fatty acid oxidation defect

Prognosis

With early delivery and intensive care most mothers recover fully, with liver tests normalising within days to weeks. Delays increase maternal and fetal mortality. It can recur, especially if the fetus has a fatty acid oxidation disorder.

Prevention

Not preventable
Early recognition in any late-pregnancy woman with vomiting, malaise or jaundice, and testing of babies and later pregnancies when a family has an LCHAD defect

Test yourself

Think of the answer, then tap the question to see it.

Which fetal enzyme deficiency is associated with acute fatty liver of pregnancy?

Long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency, a fatty acid oxidation defect.

Which laboratory finding helps distinguish it from HELLP syndrome?

Hypoglycaemia (with marked coagulopathy and raised ammonia); in HELLP, haemolysis and low platelets predominate and glucose is usually normal.

What is the typical histological finding?

Microvesicular fatty infiltration of hepatocytes.

What is the definitive treatment?

Prompt delivery after maternal stabilisation, followed by intensive supportive care.

Add to my cards (4)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: Acute Fatty Liver of Pregnancy (Cleveland Clinic, 2024).

← All conditions

Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake

Representative model, for educational purposes only.

Liver highlighted on the Durgical 3D model