Acute Fatty Liver of Pregnancy
A life-threatening third-trimester liver failure caused by microvesicular fat accumulation, requiring immediate delivery.
Emergency Management: Massive postpartum hemorrhage secondary to severe coagulopathy/DIC.
Acute Fatty Liver of Pregnancy (AFLP) is a rare, life-threatening obstetric emergency occurring typically in the third trimester or early postpartum period. It is characterized by microvesicular fatty infiltration of hepatocytes leading to rapid, progressive acute liver failure, encephalopathy, and coagulopathy. It often requires immediate delivery to reverse the hepatic insult.
Detailed Overview
AFLP is driven by a maternal-fetal mismatch in mitochondrial fatty acid oxidation. It is highly associated with fetal homozygosity for a mutation in long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD). The resulting accumulation of long-chain fatty acids in the maternal bloodstream overwhelms the maternal liver, leading to massive microvesicular steatosis. Due to the high risk of maternal and fetal mortality, prompt recognition via the Swansea criteria and expedited delivery are critical.
Epidemiology & Demographics
Incidence is roughly 1 in 7,000 to 1 in 20,000 pregnancies. More common in primigravidas, multiple gestations, and male fetuses. Typically presents between 32 and 38 weeks of gestation.
Etiological Mechanism
Genetic defect in fetal mitochondrial beta-oxidation of fatty acids, specifically LCHAD deficiency (G1528C mutation).
Primary Causes
Accumulation of un-metabolized long-chain fatty acids produced by the fetus/placenta crossing into maternal circulation.
When a fetus is homozygous for the LCHAD mutation and the mother is heterozygous, the fetus cannot process long-chain fatty acids. These fatty acids accumulate and cross the placenta into the maternal circulation. The heterozygous mother has reduced capacity to metabolize this sudden influx, leading to intracellular accumulation of fat within maternal hepatocytes (microvesicular steatosis) without prominent necrosis. This rapidly impairs hepatic function, causing profound hypoglycemia, severe coagulopathy, hyperammonemia, and eventually multi-organ system failure.
Diagnostic Criteria & Guidelines
Diagnosed using the Swansea criteria (requires 6 or more): vomiting, abdominal pain, polydipsia/polyuria, encephalopathy, elevated bilirubin (>0.8 mg/dL), hypoglycemia (<72 mg/dL), elevated uric acid (>5.7 mg/dL), leukocytosis (>11,000/microL), ascites, elevated transaminases (>42 U/L), elevated ammonia (>47 micromol/L), prolonged PT (>14s), microvesicular steatosis on biopsy.
Immediate stabilization and prompt delivery of the fetus, regardless of gestational age. Give 10% or 50% Dextrose infusion to maintain blood glucose > 70 mg/dL.
Second-Line & Adjunctive Therapy
Aggressive blood product transfusion: Fresh Frozen Plasma (FFP), Cryoprecipitate, and Platelets to correct DIC and coagulopathy prior to/during delivery.
Surgical & Procedural Management
Cesarean delivery if labor induction is not rapidly progressing or if fetal/maternal status deteriorates rapidly.
Patient Counseling & Advice
Discuss the high risk of recurrence (up to 25% if parents are carriers of the mutation) in future pregnancies. Inform that maternal liver function usually normalizes completely within a few weeks postpartum.
Follow-Up & Monitoring Schedule
Daily comprehensive metabolic panels and coagulation profiles postpartum until complete resolution. Test the neonate for LCHAD deficiency immediately after birth.
Preventive Strategies
No primary prevention. Close monitoring in subsequent pregnancies for early signs.
Maternal mortality is around 1-5% (drastically reduced from 85% with early delivery). Fetal mortality is 10-20%. Liver function typically returns to normal in survivors.