Preeclampsia !

Preeclampsia is new high blood pressure after 20 weeks of pregnancy with protein in the urine or organ damage; it can worsen fast and endanger mother and baby.

Updated 2026-10-29

Structures involved

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

In biochemistry

In histology

Placenta

In embryology

In the clinical exam

In physiology

Why it happens

What it is

A pregnancy disorder with new high blood pressure after 20 weeks and either proteinuria or signs of organ damage. It can worsen quickly to eclampsia or HELLP syndrome, and delivery is the only definitive treatment.

Who gets it

Hypertensive disorders of pregnancy are among the leading causes of maternal death in Colombia and Latin America. Preeclampsia is more common in first pregnancies and in women with chronic hypertension, diabetes or kidney disease. It can also appear for the first time after delivery.

Causes

Abnormal placentation: the spiral arteries are not fully remodelled
Placental ischaemia releasing anti-angiogenic factors into the mother's circulation
Exact cause not fully understood; immune and genetic factors take part

Risk factors

Preeclampsia in a previous pregnancy
First pregnancy
Chronic hypertension, pregestational diabetes, chronic kidney disease
Autoimmune disease (antiphospholipid syndrome, lupus)
Multiple pregnancy
Obesity, older maternal age, assisted reproduction, family history

Pathophysiology

Trophoblast invasion of the spiral arteries is shallow, so they stay narrow and the placenta is poorly perfused. The stressed placenta releases anti-angiogenic factors that cause widespread maternal endothelial dysfunction, with vasoconstriction, capillary leak and platelet activation. This damages the kidneys, liver, brain, lungs and clotting system.

Classification

Preeclampsia without severe features
Preeclampsia with severe features: very high blood pressure, low platelets, raised liver enzymes, kidney impairment, pulmonary oedema, new headache or visual changes
HELLP syndrome: haemolysis, elevated liver enzymes, low platelets
Eclampsia: new seizures not explained by another cause
Superimposed on chronic hypertension; postpartum preeclampsia

Symptoms and signs

Often none: found at a routine blood pressure check
New hypertension after 20 weeks
Swelling of the face and hands, rapid weight gain (not diagnostic on their own)
Headache
Visual disturbance: blurring, flashing lights
Upper abdominal or right upper quadrant pain, nausea, vomiting

Diagnosis

Clinical: Blood pressure of 140/90 mmHg or more on two occasions after 20 weeks in a woman previously normotensive, plus proteinuria or organ dysfunction. Symptoms of severe features are asked about at every visit.
Tests: Urine protein (protein-to-creatinine ratio or 24-hour collection), full blood count with platelets, creatinine, liver enzymes, LDH and blood film for haemolysis. Angiogenic markers are used in some centres.
Imaging: Obstetric ultrasound for fetal growth, amniotic fluid and Doppler of the umbilical artery; continuous fetal heart monitoring as needed.

Differential diagnosis

Gestational hypertension (no proteinuria or organ damage)
Chronic hypertension
Acute fatty liver of pregnancy
Thrombotic thrombocytopenic purpura or haemolytic uraemic syndrome
Epilepsy or other causes of seizures (for eclampsia)

Goal of treatment

Protect the mother from stroke, seizures and organ damage, time delivery to balance maternal risk against fetal maturity, and watch for postpartum worsening.

Treatment

Medical: Antihypertensives considered safe in pregnancy (for example labetalol, hydralazine or nifedipine) for severe-range pressure; ACE inhibitors and ARBs are avoided during pregnancy.
Acute: Magnesium sulfate as the standard prophylaxis and treatment of eclamptic seizures, with monitoring for toxicity.
Medical: Antenatal corticosteroids for fetal lung maturity when preterm delivery is expected.
Procedure: Delivery is the definitive treatment: commonly at 37 weeks without severe features, and earlier once the mother is stabilised when there are severe features, HELLP or eclampsia.
Follow-up: Close monitoring of blood pressure, symptoms, labs and fetal wellbeing, continuing for days after birth.

Drugs for this condition

Complications

Eclampsia
HELLP syndrome and disseminated intravascular coagulation
Stroke (haemorrhagic or posterior reversible encephalopathy)
Placental abruption
Pulmonary oedema, acute kidney injury, liver haematoma or rupture
Fetal growth restriction, preterm birth, stillbirth

Prognosis

Most signs resolve within days to weeks after delivery, but the condition can recur in later pregnancies. Women who have had preeclampsia carry a higher lifelong risk of hypertension and cardiovascular disease, which justifies long-term follow-up.

Prevention

Low-dose aspirin from early in the second trimester for women at high risk
Calcium supplementation where dietary calcium intake is low
Blood pressure and urine checks at every prenatal visit

Test yourself

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

From what gestational age can preeclampsia be diagnosed?

After 20 weeks of gestation (and up to several weeks after delivery).

What does HELLP stand for?

Haemolysis, elevated liver enzymes and low platelets.

What drug is the standard prophylaxis against eclamptic seizures?

Magnesium sulfate.

What is the only definitive treatment of preeclampsia?

Delivery of the baby and placenta.

Which antihypertensive classes are avoided in pregnancy?

ACE inhibitors and angiotensin receptor blockers, because of fetal toxicity.

Add to my cards (5)

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

Sources: Preeclampsia (StatPearls (NCBI Bookshelf), 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.

Uterine artery highlighted on the Durgical 3D model