19th June 2026

Pre-eclampsia and eclampsia

Background

Pre-eclampsia is a systemic syndrome in pregnancy that usually occurs after 20 weeks’ gestation, characterised by hypertension and proteinuria. The mechanism underlying pre-eclampsia has not been fully elucidated; however, it is thought to be related to abnormal placentation and inadequate trophoblastic invasion of the uterine spiral arteries, leading to vasoconstriction, increased systemic vascular resistance, and decreased organ perfusion. Eclampsia is a complication of pre-eclampsia, characterised by seizures.

Epidemiology

Nearly 2-8% pregnancies worldwide are implicated by pre-eclampsia. Eclampsia is a rare complication, with an incidence of 1 in 2,000 pregnancies.

Risk factors 

• Nulliparity 
• Previous maternal history or family history
• BMI > 30
• Maternal age > 40 years
• Multiple pregnancy
• > 10-year interval since previous pregnancy
• Sub-fertility 
• Gestational hypertension
• Pre-existing diabetes
• Pre-existing renal or vascular disease
• PCOS
• Autoimmune disease

Clinical features

• The key clinical features of pre-eclampsia are hypertension and proteinuria after 20 weeks’ gestation
• Women may be asymptomatic and diagnosed at a routine clinic visit
• Headaches (usually frontal): indicates severe pre-eclampsia 
• Visual disturbances
• Peripheral oedema
• Upper abdominal pain (usually right upper quadrant)
• Nausea and vomiting 
• Breathlessness (due to pulmonary oedema): one of the main causes of maternal mortality 
• Seizures: requires prompt admission to ICU, stabilisation and delivery
• Oliguria

HELLP syndrome is a variant of severe pre-eclampsia characterised by haemolysis, elevated liver enzymes, and low platelets.

Diagnosis and investigations

Diagnosis is based on the presence of the following after 20 weeks’ gestation:

• Hypertension: SBP ≥ 140 mmHg and/or a DBP ≥ 90 mmHg on 2 occasions at least 4 hours apart
• Proteinuria: ≥ 30 mg/mmol on PCR or ≥ 0.3g/24 hours or ≥ 1+ on a urine dipstick

After diagnosing pre-eclampsia, further testing should be performed, including foetal assessment for complications and maternal testing for systemic involvement. A summary of the investigations can be found in Table 1.

Table 8. Investigations for pre-eclampsia

PCR, protein: creatinine ratio; PIGF, placental growth factor

Severity classification of pre-eclampsia:

• Hypertension: BP of 140/90 – 159/109 mmHg
• Severe hypertension: BP of ≥ 160/110 mmHg

Complications

Maternal complications

• Seizures (eclampsia)
• Placental abruption
• Pulmonary oedema
• Pregnancy-associated stroke
• Cardiovascular disease 
• Renal failure
• Death

Foetal complications 

• IUGR
• Pre-term delivery
• Intrauterine death

Management

Managing pre-eclampsia requires attention to the following critical considerations: 

• Monitoring
• Delivery: date and method
• Controlling blood pressure
• Controlling seizures
• Postnatal fluid management

Important considerations

• Antihypertensive treatment: choice should be based on pre-existing treatment, possible side effects, maternal vs foetal risk, and the woman’s preference. Combination therapy may be required.
• Corticosteroids (e.g. betamethasone) to promote foetal lung maturation, as indicated
• Magnesium sulphate if planned early delivery. It is the treatment of choice for eclampsia. Monitor for signs of magnesium toxicity (e.g. respiratory depression and loss of reflexes); calcium gluconate may be used as a reversal agent.
• Delivery: the definitive management of pre-eclampsia, however it may take a few days to resolve completely. Indications for planned early delivery < 37 weeks may include the following:
  • Inability to control maternal BP despite ≥ 3 classes of antihypertensives
  • Maternal pulse oximetry < 90%
  • Progressive deterioration in blood results
  • Ongoing neurological features, e.g. severe intractable headache, repeated visual scotomata
  • Placental abruption
  • Reversed end-diastolic flow in umbilical artery doppler velocimetry, a non-reassuring CTG, or stillbirth

Table 9. Management of pre-eclampsia

fullPIERS, Pre-eclampsia Integrated Estimate of RiSk; PREP-S, Prediction of complications in early-onset pre-eclampsia (using a survival model).

Postnatal investigation, monitoring and treatment

• Measure BP at least once between day 3 and 5 after birth, then on alternate days until normal, if BP was abnormal
• Continue antihypertensive treatment if required. Start treatment if BP ≥ 150/100 mmHg and they were not treated during pregnancy. Reduce treatment dosages if BP falls < 130/80 mmHg
• Follow-up with GP or specialist 6-8 weeks after birth, or 2 weeks after transfer to community care for women who remain on antihypertensive treatment
• The main risk to the mother in this period is fluid overload; therefore, fluid management is crucial. NICE guidelines fluid restriction to 80 ml/hour