Preeclampsia: Symptoms, Types, Causes and Treatment

Preeclampsia is one of the most critical and complex conditions faced in pregnancy. Often described as a “disease of theories,” it can affect both mother and baby, sometimes with life-threatening consequences. Yet, despite its seriousness, preeclampsia remains poorly understood by many outside the medical community. This article provides a comprehensive, evidence-based overview of its symptoms, types, causes, and current treatment strategies, helping demystify this multifaceted syndrome.

Symptoms of Preeclampsia

Preeclampsia often develops silently, but its signs and symptoms can escalate quickly. Recognizing these early is vital for timely treatment and better health outcomes for both mother and child. Symptoms can be diverse, ranging from subtle to severe, and sometimes overlap with common pregnancy discomforts, making awareness all the more crucial.

Symptom	Description	Severity	Source
Hypertension	Blood pressure ≥140/90 mmHg after 20 weeks	Mild-Severe	1 2 6
Proteinuria	Protein in urine (≥300 mg/24h)	Mild-Severe	1 2 14
Edema	Swelling (especially hands, face, feet)	Mild	2 5
Visual Changes	Blurred vision, scotomata, blindness	Severe	3 4
Headache	Persistent, often severe	Severe	2 5
Abdominal Pain	Often right upper quadrant	Severe	1 2
Nausea/Vomiting	Unexplained, persistent	Severe	1 2
HELLP Syndrome	Hemolysis, elevated liver enzymes, low platelets	Life-threatening	1 6 14
Fetal Growth Restriction	Slowed fetal growth	Any	2 14

Table 1: Key Symptoms

Blood Pressure and Proteinuria: The Hallmarks

The defining features of preeclampsia are new-onset hypertension and proteinuria after 20 weeks of gestation in a previously normotensive woman. Blood pressure readings of 140/90 mmHg or higher on two occasions are considered concerning. Proteinuria is usually detected as ≥300 mg in a 24-hour urine sample, but even in its absence, preeclampsia can be diagnosed if organ dysfunction is present 1 2 6 14.

Edema and Other Manifestations

While edema (swelling) is common in pregnancy, in preeclampsia it is often pronounced and may affect the face, hands, or even the whole body. Other symptoms include:

• Severe, persistent headaches
• Visual disturbances (blurred vision, flashes, loss of vision)
• Pain in the upper abdomen, particularly under the ribs on the right side (suggesting liver involvement)
• Nausea and vomiting not related to other causes

These symptoms may indicate severe disease and require urgent medical attention 2 3 4 5 14.

HELLP Syndrome and Organ Involvement

A dangerous complication is HELLP syndrome—marked by hemolysis (breakdown of red blood cells), elevated liver enzymes, and low platelets. This can occur in up to 20% of severe cases, and may also signal serious liver or coagulation problems 1 6 14. Kidney dysfunction, liver injury (manifested as pain or abnormal liver function tests), and brain involvement (causing seizures or altered mental status, progressing to eclampsia) are possible 1 2.

Fetal Consequences

Preeclampsia affects the placenta, often resulting in fetal growth restriction due to reduced blood flow. If left untreated, it can threaten fetal survival 2 14.

Types of Preeclampsia

Preeclampsia is not a single disease but a syndrome with multiple subtypes. Understanding its forms is vital for prognosis and tailored care.

Type	Defining Features	Risk/Outcome	Source
Early-Onset	<34 weeks gestation, placental dysfunction	Higher risk	6 7 9 10
Late-Onset	≥34 weeks, maternal cardiovascular intolerance	Moderate risk	7 9 10
Type I ("Placental")	Placental malperfusion, severe, FGR common	Severe	8 9 10
Type II ("Maternal")	Maternal vascular maladaptation, later onset	Less severe	8 9 10
HELLP Syndrome	Hemolysis, ↑Liver enzymes, ↓Platelets	Severe, multi-organ	1 6 14

Table 2: Preeclampsia Types and Subtypes

Early-Onset vs. Late-Onset

Early-onset preeclampsia appears before 34 weeks of pregnancy and is often linked to poor placental development, leading to more severe symptoms, higher risks for both mother and baby, and a greater chance of fetal growth restriction or preterm delivery 6 7 9 10.

Late-onset preeclampsia develops at or after 34 weeks and is more often related to the mother's cardiovascular system failing to adapt to pregnancy demands. It tends to be less severe but can still lead to complications 7 9 10.

Pathophysiological Subtypes: Type I and Type II

Recent research proposes two main pathophysiological subtypes:

• Type I ("Placental"): Driven by placental dysfunction, shallow trophoblast invasion, and significant antiangiogenic imbalance. Presents earlier and is associated with severe disease and fetal growth restriction 8 9 10.
• Type II ("Maternal"): Results from maladaptation of the mother’s cardiovascular system, usually appears later, and the placenta is less severely affected 8 9 10.

HELLP Syndrome

HELLP syndrome is considered a severe form of preeclampsia or a related entity. It involves hemolysis, elevated liver enzymes, and low platelets, and can occur alongside classic symptoms or independently 1 6 14.

Why Classification Matters

Recognizing these types helps guide monitoring, anticipate complications, and personalize interventions. It also highlights that preeclampsia is a dynamic, multisystem disease, not a one-size-fits-all diagnosis 7 10.

Causes of Preeclampsia

The origins of preeclampsia are complex and multifactorial, involving genetics, the immune system, the placenta, and maternal health. Understanding these factors is crucial for prevention and research into new therapies.

Cause/Factor	Mechanism/Role	Key Notes	Source
Abnormal Placentation	Shallow invasion, ischemia	Central mechanism	1 11 12 13 14
Antiangiogenic Factors	Excess sFlt-1, endoglin → endothelial injury	Biomarker, target	1 11 14 15
Immune Imbalance	↑Pro-inflammatory T-cells, ↓Tregs	Chronic inflammation	12 13
Genetic/Autoimmune	Family history, immune tolerance breakdown	Higher risk	13 14
Metabolic/Health Risks	Obesity, diabetes, hypertension	Modifiable risks	13 14
Infections	Periodontal/gut dysbiosis, viral (e.g., SARS-CoV-2)	Emerging evidence	13

Table 3: Major Causes and Risk Factors

Abnormal Placentation and Placental Ischemia

The most widely accepted theory is that preeclampsia starts with abnormal development of the placenta. In normal pregnancy, placental cells invade and remodel maternal blood vessels to ensure sufficient blood flow. In preeclampsia, this process is shallow or incomplete, leading to placental ischemia (reduced oxygen) and the release of factors that damage the maternal endothelium 1 11 12 13 14.

Antiangiogenic Factors

The stressed placenta releases excessive antiangiogenic factors, notably soluble fms-like tyrosine kinase-1 (sFlt-1) and soluble endoglin. These circulating molecules disrupt blood vessel health, leading to hypertension, proteinuria, and organ injury—central features of the disorder 1 11 14 15.

Immune System and Inflammation

Preeclampsia is marked by an immune imbalance: increased pro-inflammatory T-cells and decreased regulatory T-cells (Tregs) drive chronic inflammation and vascular dysfunction. This immune dysregulation is thought to be triggered by placental ischemia and may underlie the hypertension and systemic symptoms 12 13.

Genetic, Metabolic, and Other Risk Factors

• Family history and genetic predisposition increase risk.
• Obesity, diabetes, and pre-existing hypertension are notable contributors.
• Autoimmune conditions can disrupt maternal-fetal tolerance.
• Infections such as periodontal disease and possibly viral infections (e.g., COVID-19) have been linked to increased risk 13 14.

The Role of Maternal Cardiovascular Health

Some subtypes of preeclampsia, especially late-onset or Type II, may arise from underlying maternal cardiovascular maladaptation to pregnancy, rather than primary placental dysfunction 9 10.

Treatment of Preeclampsia

Preeclampsia poses a unique challenge: the only definitive cure is delivery, yet premature birth carries its own risks. Treatment is therefore aimed at balancing maternal safety and fetal maturity, while managing symptoms and preventing complications.

Treatment	Purpose/Mechanism	Indication/Timing	Source
Delivery	Removes placenta (disease source)	Definitive cure	1 2 8 11
Antihypertensives	Lower maternal blood pressure	Severe/mild cases	19
Magnesium Sulfate	Prevent seizures (eclampsia)	Severe preeclampsia	3 19
Corticosteroids	Accelerate fetal lung maturity	Preterm delivery	19
Low-dose Aspirin	Prevention in high-risk women	Prophylactic	19
Investigational	PPIs, Sildenafil, Resveratrol	Experimental	15 16 17 18

Table 4: Main Treatment Strategies

Delivery: The Only Cure

The only definitive treatment for preeclampsia is delivery of the baby and placenta. The timing depends on disease severity and fetal maturity. For severe cases, especially after 34 weeks, prompt delivery is usually indicated. For less severe cases, doctors may try to prolong pregnancy under careful monitoring 1 2 8 11.

Blood Pressure Control

Antihypertensive medications are used to lower blood pressure and prevent maternal complications:

• Mild cases: Slow-release nifedipine is often recommended.
• Severe cases: Labetalol is the drug of choice 19.

Seizure Prevention

Magnesium sulfate is administered to prevent seizures (eclampsia), particularly in severe preeclampsia or when neurological symptoms develop 3 19.

Fetal Protection

Corticosteroids are given to speed up fetal lung development if early delivery is anticipated, improving neonatal outcomes 19.

Prevention

Low-dose aspirin is recommended for women at high risk of preeclampsia, as it may reduce incidence if started early in pregnancy 19.

Investigational and Adjunctive Therapies

Research into new treatments is ongoing:

• Proton pump inhibitors (PPIs): Shown to reduce antiangiogenic factors and endothelial dysfunction in preclinical studies 15.
• Sildenafil: May improve uteroplacental blood flow and lower blood pressure in experimental models 17.
• Resveratrol: Reduces antiangiogenic factors and inflammation, though effects on the endothelium are mixed 18.
• Antioxidants: While some benefit in fetal growth restriction has been noted, they have not shown clear preventive benefit for preeclampsia itself 16.

Monitoring and Support

Women with preeclampsia require close monitoring for worsening symptoms, organ dysfunction, and fetal well-being. Hospitalization may be necessary in severe cases 1 2 11.

Conclusion

Preeclampsia is a complex, multisystem disorder with serious implications for both mother and baby. Early recognition, accurate classification, and timely intervention are essential for optimal outcomes. While birth remains the only cure, advances in understanding its causes and types are paving the way for improved prevention, earlier diagnosis, and future therapies.

Key Takeaways:

• Symptoms: New hypertension, proteinuria, edema, headaches, visual and abdominal symptoms, and, in severe cases, HELLP syndrome and fetal growth restriction 1 2 3 4 5 6 14.
• Types: Classified by time of onset (early vs. late), underlying mechanism (placental vs. maternal), and presence of HELLP syndrome 6 7 8 9 10 14.
• Causes: Multifactorial—abnormal placentation, antiangiogenic factors, immune imbalance, genetics, metabolic health, and infections all play roles 1 11 12 13 14 15.
• Treatment: Delivery is the only cure; supportive therapies include antihypertensives, magnesium sulfate, corticosteroids, and investigational agents in research settings 1 2 8 11 15 16 17 18 19.

By staying informed and vigilant, patients, families, and healthcare providers can work together to improve the prognosis and quality of life for those affected by preeclampsia.