HELLP Syndrome

Jan 23, 2020
11 min read

Updated: Nov 9

HELLP syndrome represents one of the most dangerous failures in maternal medicine, a hypertensive disorder that dismantles the body’s blood, liver, and clotting systems with little warning. It strikes roughly 1 in 1,000 pregnancies, often in the final trimester or shortly after delivery, yet up to 20 percent of cases occur without the hallmark signs of preeclampsia. The result is delayed recognition, preventable organ failure, and death in settings where early laboratory screening could have intervened. Here, we dissect the pathophysiology, diagnostic thresholds, and treatment imperatives that define HELLP, exposing how inconsistent testing, systemic bias, and fragmented obstetric protocols continue to cost women their lives.

Overview

What is HELLP syndrome?

HELLP syndrome is a life-threatening obstetric complication that affects the liver, blood, and coagulation system during pregnancy. It represents one of the most severe variants within the hypertensive disorders of pregnancy (HDP) spectrum and requires immediate medical recognition and intervention. The condition most commonly emerges in the third trimester (28–40 weeks) but can occur as early as 20 weeks of gestation or within the first seven days postpartum.

The name HELLP describes the triad of laboratory abnormalities that define the disorder:

H — Hemolysis: The destruction of red blood cells, leading to anemia, tissue hypoxia, and endothelial injury.
EL — Elevated Liver Enzymes: Markers of hepatocellular injury (AST, ALT) indicating liver inflammation or microvascular damage.
LP — Low Platelet Count: Thrombocytopenia due to platelet consumption and vascular activation, impairing the body’s ability to control bleeding.

HELLP is frequently associated with preeclampsia, a hypertensive condition characterized by elevated blood pressure and proteinuria, but it can also arise independently, with up to 20 percent of HELLP cases presenting without hypertension or proteinuria. This makes laboratory screening essential, as the absence of high blood pressure does not exclude severe disease.

Comparison

How does HELLP differ from preeclampsia?

While HELLP syndrome shares its pathophysiology with preeclampsia—both of which are driven by endothelial dysfunction, abnormal placentation, and systemic inflammation—it represents a distinct clinical entity with hematologic and hepatic involvement. Preeclampsia primarily affects vascular tone and renal function, while HELLP introduces widespread microangiopathic hemolysis and hepatic necrosis, sharply increasing the risk of disseminated intravascular coagulation (DIC), stroke, and maternal mortality.

Epidemiologic data show that 8 percent of pregnancies in the United States are complicated by preeclampsia, and 10 to 20 percent of those cases progress to HELLP syndrome. The overall prevalence of HELLP is estimated between 0.1 and 0.6 percent of all pregnancies, translating to roughly 4,000–25,000 cases annually in the U.S.

Symptoms

What are the most common signs and symptoms of HELLP syndrome?

HELLP syndrome often develops insidiously and can mimic benign pregnancy discomfort or viral illness. However, early symptoms mark a progressing vascular and hepatic crisis.

Common clinical signs include:

Right upper-quadrant or epigastric pain (present in >90% of cases) due to hepatic distension or subcapsular hematoma
Severe or persistent headache, visual disturbances, and nausea or vomiting
Edema and rapid weight gain secondary to capillary leak and endothelial injury
Fatigue, malaise, or dyspnea from anemia and early fluid overload
Pain with deep inspiration or referred shoulder pain is, possible warning sign of liver capsule rupture or pulmonary involvement

In severe or rapidly deteriorating cases, patients may experience:

Uncontrolled bleeding or bruising due to thrombocytopenia
Seizures resulting from eclampsia or neurological changes from hypertensive encephalopathy
Jaundice or markedly abnormal liver function tests

Because these symptoms overlap with viral hepatitis, gallbladder disease, gastroenteritis, and anxiety disorders, diagnostic delay is common and dangerous. Up to 30 percent of HELLP-related maternal deaths occur after the initial diagnosis was missed or minimized as “normal postpartum recovery.”

Timely laboratory evaluation—including complete blood count, peripheral smear, liver enzymes, LDH, and coagulation profile—is critical for diagnosis and survival. Early recognition and delivery remain the only definitive interventions.

Causes

What causes HELLP syndrome?

The exact cause of HELLP syndrome remains complex and multifactorial, involving an interplay between abnormal placentation, endothelial injury, immune dysregulation, and coagulation pathway activation. Current research indicates that HELLP represents an advanced manifestation within the preeclampsia–eclampsia spectrum, driven by microangiopathic hemolysis and systemic inflammation rather than a single pathogenic event.

During normal pregnancy, placental development requires remodeling of maternal spiral arteries to ensure adequate blood flow. In HELLP, defective trophoblastic invasion leads to placental hypoxia, which in turn releases inflammatory mediators (such as TNF-α, IL-6, and sFlt-1) that damage the vascular endothelium. This cascade promotes platelet activation, red-cell fragmentation, and hepatic microthrombi formation, the hallmarks of hemolysis, elevated liver enzymes, and low platelets.

Because many of its symptoms—such as abdominal pain, fatigue, nausea, and edema—overlap with common pregnancy discomforts and gastrointestinal disorders, up to 25% of cases are initially misdiagnosed or delayed in recognition. The absence of hypertension in 15–20% of cases further contributes to diagnostic error.

Risk Factors

What risk factors are associated with HELLP syndrome?

Although HELLP syndrome can develop suddenly and without clear warning, several maternal and medical factors are known to increase susceptibility. These include both pregnancy-specific and chronic health conditions that contribute to vascular injury, endothelial dysfunction, and placental ischemia.

History of preeclampsia or eclampsia: Approximately 10–20% of patients with these conditions go on to develop HELLP syndrome.
Prior history of HELLP syndrome: The recurrence rate in subsequent pregnancies ranges from 12–19%, underscoring the importance of close surveillance in women with a prior episode.
Maternal age over 35 years: Advanced maternal age has been consistently associated with a higher risk.
Multiparity: Women who have had multiple prior births face a higher likelihood of HELLP, particularly when combined with hypertensive disorders.
Chronic hypertension: Preexisting high blood pressure predisposes patients to placental insufficiency and vascular stress that can trigger HELLP.
Renal disease: Impaired kidney function increases systemic inflammation and hemodynamic instability, contributing to endothelial injury.
Diabetes mellitus: Both type 1 and type 2 diabetes heighten oxidative stress and vascular dysfunction, elevating risk.
Autoimmune disorders: Conditions such as systemic lupus erythematosus and antiphospholipid syndrome (APS) are significant risk factors due to their impact on coagulation and microvascular integrity.
Race and genetic background: Some epidemiologic studies have found higher incidence among White and Caucasian populations, although results vary across cohorts and may reflect differences in study design or access to prenatal care.

Collectively, these factors create a biological environment that disrupts placental blood flow, damages the endothelial lining, and accelerates the cascade of hemolysis, elevated liver enzymes, and low platelet count that defines HELLP syndrome.

Complications

What are the most common complications of HELLP syndrome?

HELLP syndrome is a rapidly progressive obstetric emergency that affects multiple organ systems and can result in severe maternal and fetal morbidity if not promptly recognized and managed. Complications arise from widespread endothelial injury, intravascular coagulation, and multi-organ microangiopathy. Maternal complications occur in up to 40% of cases, often requiring intensive care support and multidisciplinary management.

Disseminated Intravascular Coagulation (DIC)

Disseminated intravascular coagulation (DIC) develops in approximately 15–20% of patients with HELLP syndrome and represents one of its most life-threatening hematologic complications. The condition is triggered by systemic activation of the coagulation cascade, leading to widespread microthrombi formation, consumption of clotting factors, and severe thrombocytopenia. As clotting factors are depleted, patients become profoundly coagulopathic, increasing the risk of massive postpartum hemorrhage and multiorgan failure. Laboratory findings typically reveal prolonged prothrombin and activated partial thromboplastin times, low fibrinogen, and elevated D-dimer levels, necessitating aggressive replacement of blood products and correction of the underlying cause.

Hepatic Rupture or Subcapsular Hematoma

Hepatic rupture or subcapsular hematoma of the liver occurs in approximately 1–2% of HELLP cases and carries one of the highest maternal mortality rates—often exceeding 30%. The event results from hepatic sinusoidal obstruction and intraparenchymal hemorrhage leading to capsular distention and eventual rupture. Clinically, it presents with severe right upper quadrant or epigastric pain, shoulder pain from diaphragmatic irritation, hypotension, and signs of hypovolemic shock. Immediate recognition is critical, as rapid surgical intervention and hemodynamic stabilization determine survival. Imaging, typically via CT or MRI, confirms the diagnosis, and management often requires coordinated care between obstetrics, hepatobiliary surgery, and critical care.

Acute Kidney Injury (AKI)

Acute kidney injury complicates 10–15% of severe HELLP cases, typically resulting from microangiopathic hemolysis, renal vasospasm, and hypoperfusion secondary to endothelial damage. Oliguria and rising serum creatinine indicate worsening renal function. In some patients, hemoglobinuria from intravascular hemolysis further damages renal tubules, exacerbating injury. Management focuses on restoring intravascular volume, controlling blood pressure, and correcting coagulation abnormalities. In severe cases, temporary renal replacement therapy may be required until renal function recovers postpartum.

Pulmonary Edema

Pulmonary edema in HELLP syndrome is usually multifactorial, resulting from increased vascular permeability, reduced colloid oncotic pressure from hypoalbuminemia, and excessive intravenous fluid administration. It may develop even in patients without overt preeclampsia and represents a major cause of maternal respiratory failure. Patients present with dyspnea, hypoxia, and diffuse crackles on lung examination. Management includes oxygen support, judicious fluid restriction, and diuretics once hemodynamic stability is achieved. Severe cases may necessitate noninvasive or mechanical ventilation.

Eclampsia

Eclampsia, defined as the occurrence of new-onset seizures in a patient with preeclampsia or HELLP, can occur despite prior control of hypertension or proteinuria. It reflects escalating cerebral endothelial dysfunction, vasogenic edema, and altered cerebral autoregulation. Neurological manifestations include headache, visual disturbances, confusion, and seizure activity, which may progress to coma if untreated. Management involves stabilization, magnesium sulfate administration, and expedited delivery once maternal condition permits.

Placental Abruption

Placental abruption, the premature separation of the placenta from the uterine wall, is a well-documented complication of HELLP syndrome and other hypertensive disorders of pregnancy. The process results from widespread vascular injury and impaired placental perfusion, leading to hemorrhage between the placenta and uterine wall. Patients present with vaginal bleeding, uterine tenderness, and fetal distress. The condition poses an immediate risk to both mother and fetus, with maternal blood loss and disseminated intravascular coagulation contributing to significant morbidity. Prompt recognition and emergent delivery, often by cesarean section, are essential to optimize maternal and neonatal outcomes.

Fetal Complications

Are there possible fetal and neonatal complications associated with HELLP syndrome?

Fetal outcomes are directly tied to the degree of maternal instability and placental perfusion.

Preterm delivery: Occurs in up to 70% of cases, with approximately half resulting from medically indicated early delivery to preserve maternal health.
Intrauterine Growth Restriction (IUGR): Caused by chronic placental insufficiency and reduced oxygen delivery to the fetus.
Perinatal mortality: Reported rates range from 7% to 20%, influenced by gestational age at diagnosis, access to tertiary care, and the timing of delivery.

Together, these complications highlight the urgency of early diagnosis, multidisciplinary management, and rapid delivery planning in patients with HELLP syndrome.

Diagnosis

How is HELLP syndrome diagnosed?

Diagnosis of HELLP syndrome requires integration of both clinical presentation and confirmatory laboratory results. Because symptoms can overlap with preeclampsia, acute fatty liver of pregnancy, and thrombotic microangiopathies, early biochemical screening is critical.

Key diagnostic criteria include:

Hemolysis: Evidence of red blood cell destruction, marked by elevated lactate dehydrogenase (LDH >600 U/L), decreased hematocrit (<30%), elevated total bilirubin (>1.2 mg/dL), and schistocytes or burr cells on peripheral smear.
Elevated liver enzymes: AST or ALT ≥70 U/L, reflecting hepatic injury or periportal necrosis.
Low platelets: Platelet count <100,000/mm³, with or without concurrent coagulopathy (elevated D-dimer, prolonged PT/aPTT).

Hypertension and proteinuria, both hallmarks of preeclampsia, may be absent in up to 20% of patients, leading to delayed recognition if laboratory screening is not performed. Advanced imaging, such as abdominal ultrasound or CT, can identify hepatic hematomas, subcapsular hemorrhage, or hepatic rupture, which are associated with severe maternal morbidity and mortality.

Clinical Classification

How is HELPP syndrome classified?

HELLP syndrome is stratified according to platelet nadir and extent of hepatic dysfunction, which correlate strongly with clinical severity, transfusion requirements, and perinatal outcomes. Standard classification is determined utilizing the Tennessee or Mississippi system, which is based on three possible categorizations:

Class I (Severe): Platelets <50,000/mm³ — highest risk for disseminated intravascular coagulation (DIC), hepatic rupture, and renal failure.
Class II (Moderate): Platelets 50,000–100,000/mm³ — significant hepatic involvement, rising LDH (>600 U/L), and worsening hemolysis.
Class III (Mild): Platelets 100,000–150,000/mm³ — early or evolving HELLP; requires close monitoring and serial labs every 6–12 hours.

Patients may progress rapidly between classes, particularly if delivery is delayed. Severity classification helps determine the timing of delivery, ICU monitoring, transfusion thresholds (platelets <50,000/mm³), and the need for magnesium sulfate or corticosteroid therapy to stabilize the maternal condition before delivery.

Management and Treatment

What treatment options are available for HELPP syndrome?

The only definitive treatment for HELLP syndrome is delivery of the fetus and placenta, which removes the source of endothelial injury. According to the American College of Obstetricians and Gynecologists (ACOG, 2020) and Society for Maternal-Fetal Medicine (SMFM), immediate delivery is indicated when:

Gestational age ≥34 weeks, or
Maternal condition is deteriorating, regardless of gestational age.

For pregnancies under 34 weeks with stable maternal-fetal status, management includes:

Corticosteroids (e.g., betamethasone) to accelerate fetal lung maturity
Magnesium sulfate for seizure prophylaxis
Antihypertensives to maintain systolic BP <160 mmHg and diastolic <110 mmHg
Platelet transfusion if count <50,000/mm³ or prior to cesarean delivery
Serial laboratory monitoring of platelets, liver enzymes, and renal function every 6–12 hours

HELLP symptoms typically resolve within 48–72 hours postpartum, but careful monitoring is essential, as up to 25% of maternal deaths occur after delivery due to delayed DIC or hepatic rupture.

Outlook and Prognosis

What is my outlook following a HELLP syndrome diagnosis?

HELLP syndrome is a critical but survivable obstetric emergency where the outcome depends entirely on the speed of recognition and intervention. With timely delivery and multidisciplinary care, most women recover fully within several days postpartum as liver enzymes normalize, platelets stabilize, and hemolysis resolves. However, recovery does not equal reversal. Long-term vascular, hepatic, and metabolic sequelae can persist for months or years, underscoring the importance of postpartum surveillance.

Early diagnosis and management reduce maternal morbidity to below 25 percent, but when delayed or missed, the condition can escalate to multi-organ failure, disseminated intravascular coagulation (DIC), or hepatic rupture. In contemporary hospital settings with rapid-response obstetric and critical-care teams, maternal survival exceeds 98–99 percent, but this figure hides substantial variation between institutions, particularly in regions with limited access to high-acuity obstetric care.

Real-World Outcomes

Is HELLP syndrome life-threatening?

Yes. HELLP syndrome is one of the leading causes of maternal death in the developed world when unrecognized or undertreated. Mortality rates for mothers range from 1 to 3 percent overall, but rise sharply in cases complicated by liver rupture, stroke, or renal failure. The danger is not in its rarity but in its unpredictability, as HELLP can progress from mild malaise to organ collapse within hours.

When detected early and managed appropriately, the prognosis for both mother and infant is favorable. Maternal recovery typically occurs within 72 hours postpartum, though platelet and liver function may take up to a week to return to normal. However, recurrence risk in future pregnancies is 10–20 percent, and the risk of developing chronic hypertension or cardiovascular disease later in life is two to four times higher than in the general female population.

Fetal outcomes are determined primarily by gestational age and placental perfusion at the time of diagnosis. Overall perinatal survival rates range from 40 to 90 percent, improving markedly after 32 weeks’ gestation. Neonates born prematurely are at risk for respiratory distress, intraventricular hemorrhage, necrotizing enterocolitis, and retinopathy of prematurity, though outcomes approach those of other preterm infants of similar birth weight once stabilized.

Prevention

What steps can help prevent HELLP syndrome or slow its progression?

There is currently no definitive method to prevent HELLP syndrome, as its pathogenesis begins early in placentation, well before clinical symptoms appear. However, risk mitigation is possible through precision obstetric monitoring and targeted pharmacologic prevention.

Low-dose aspirin (81 mg daily starting at 12–16 weeks) has been shown to reduce preeclampsia risk by 10–20 percent and may indirectly lower HELLP incidence in high-risk pregnancies.
Serial blood pressure monitoring, urine protein testing, and third-trimester lab screening are essential for early detection in women with prior HELLP, autoimmune disease, or thrombophilia.
Postpartum follow-up at 6 weeks, 3 months, and 1 year should include metabolic and vascular evaluation, given the association between HELLP and future endothelial dysfunction.

Lifestyle factors, including adequate hydration, a nutrient-dense diet, stress reduction, and adherence to prenatal visits, contribute to overall maternal health but cannot substitute for medical surveillance.

Seeking Care

When should I contact my provider or seek urgent medical care?

HELLP syndrome can deteriorate rapidly. Any pregnant or postpartum woman should seek immediate emergency evaluation (call 911 in the U.S.) if experiencing:

Severe upper right abdominal or epigastric pain
Sudden vision changes or persistent headache
Shortness of breath, chest pressure, or swelling
Heavy bleeding, confusion, or seizures

Even subtle symptoms, including nausea, fatigue, or flu-like malaise in late pregnancy, warrant assessment, as up to one-third of HELLP cases present without hypertension. The safest course is to treat every warning sign as a potential emergency until proven otherwise.

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