HELLP Syndrome

HELLP syndrome refers to the constellation of Hemolysis, Elevated Liver function tests, and Low Platelet count seen in pregnant women and sometimes considered to be a severe form of preeclampsia.

  • Diagnosis
  • Background
  • Lab Tests
  • References
  • Related Topics

Indications for Testing

  • Pregnant patient presenting with clinical picture of preeclampsia, thrombocytopenia, or acute liver failure

Criteria for Diagnosis

  • Patients lacking all 3 of the criteria for HELLP (hemolysis, elevated liver enzymes, and low platelets) can be deemed partial HELLP

Laboratory Testing

  • CBC – anemia, thrombocytopenia (<100,000/mm3 to meet criteria)
    • Peripheral smear with evidence of helmet cells, burr cells, schistocytes (microangiopathic hemolysis)
  • Liver function tests
    • Aspartate aminotransferase (AST) – 2 times the upper reference limit (to meet criteria)
    • Lactate dehydrogenase (LD) – markedly elevated (≥600 U/L to meet criteria)
      • LD criteria should be based on the upper limits of normal values in the lab where specimen is processed
  • Consider other testing if clinically indicated

Differential Diagnosis


  • Incidence – 0.6% of pregnant women (ASH, 2013)
    • 5-10% of pregnancies with preeclampsia
    • 30-50% of pregnancies with eclampsia
  • Age – childbearing years
  • Sex – exclusively in pregnant or postpartum females

Risk Factors

  • Caucasian race
  • Multiparity
  • Age – >34 years
  • Presence of preeclampsia or eclampsia
  • Fetus affected with fatty acid oxidation defect – ie, defects such as long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency
  • Previous pregnancy with HELLP


  • Placenta in preeclampsia is poorly perfused, which releases factors that create endothelial dysfunction
  • Endothelial dysfunction causes platelet aggregation and altered ratio of thromboxane to prostacyclin
  • Thrombin-induced activation of the coagulation cascades leads to hemolytic anemia and multiorgan microvascular injury

Clinical Presentation

  • Usually occurs during pregnancy
    • 2/3 of patients are diagnosed antepartum
    • Typically does not present prior to 3rd trimester
    • Postpartum presentation usually within first week
  • Symptoms
    • Nonspecific – malaise, fatigue
    • Gastrointestinal – right upper quadrant pain, nausea, emesis
    • Central nervous system – headache, confusion
    • Cardiovascular – hypertension
  • Complications
    • Maternal
    • Fetal/perinatal
      • Prematurity
      • Placental insufficiency
      • Intrauterine growth restriction
      • Neonatal intraventricular hemorrhage
Tests generally appear in the order most useful for common clinical situations. Click on number for test-specific information in the ARUP Laboratory Test Directory.

CBC with Platelet Count and Automated Differential 0040003
Method: Automated Cell Count/Differential

Hepatic Function Panel 0020416
Method: Quantitative Enzymatic/Quantitative Spectrophotometry

Lactate Dehydrogenase, Serum or Plasma 0020006
Method: Quantitative Enzymatic

Hypertension in Pregnancy. American College of Obstetricians and Gynecologists. Washington, DC [Accessed: Dec 2016]

Rajasekhar A, Gernsheimer T, Stasi R, James A. 2013 Clinical Practice Guide on Thrombocytopenia in Pregnancy. American Society of Hematology. Washington, DC [Accessed: Dec 2016]

General References

Bacq Y. Liver diseases unique to pregnancy: a 2010 update. Clin Res Hepatol Gastroenterol. 2011; 35(3): 182-93. PubMed

Haram K, Svendsen E, Abildgaard U. The HELLP syndrome: clinical issues and management. A Review. BMC Pregnancy Childbirth. 2009; 9: 8. PubMed

Hepburn IS, Schade RR. Pregnancy-associated liver disorders. Dig Dis Sci. 2008; 53(9): 2334-58. PubMed

Joshi D, James A, Quaglia A, Westbrook RH, Heneghan MA. Liver disease in pregnancy. Lancet. 2010; 375(9714): 594-605. PubMed

O'Brien JM, Barton JR. Controversies with the diagnosis and management of HELLP syndrome. Clin Obstet Gynecol. 2005; 48(2): 460-77. PubMed

Sibai BM, Ramadan MK, Usta I, Salama M, Mercer BM, Friedman SA. Maternal morbidity and mortality in 442 pregnancies with hemolysis, elevated liver enzymes, and low platelets (HELLP syndrome) Am J Obstet Gynecol. 1993; 169(4): 1000-6. PubMed

Medical Reviewers

Last Update: October 2017