11/14/24, 10\:48 AM Pre-eclampsia and Eclampsia

Pre-eclampsia and Eclampsia

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Pre-eclampsia\: multisystem syndrome post-20 weeks, with hypertension, proteinuria, maternal/uteroplacental
dysfunction.
Incidence\: 2-8% of pregnancies, 0.5% develop severe form; severe pre-eclampsia can lead to eclampsia (seizures).
Aetiology\: abnormal placentation, maternal microvascular disease; leads to endothelial dysfunction, oedema, proteinuria,
hypertension.
High-risk factors\: chronic hypertension, previous hypertensive pregnancy, diabetes, kidney disease, autoimmune disease.
Moderate-risk factors\: age ≥40,
Symptoms\: headache, visual disturbance, limb/facial swelling, nausea, abdominal pain, reduced urine output.
Investigations\: BP monitoring, urine dipstick, FBC (low platelets), U&Es (renal impairment), LFTs (liver dysfunction), clotting
pro
Management\: regular monitoring (BP, proteinuria, blood tests), fetal monitoring (CTG, ultrasound, Doppler), aspirin,
antihypertensives (labetalol, nifedipine, methyldopa).
Severe pre-eclampsia\: BP ≥160/110 mmHg, hospital admission, risk scoring, early delivery if indicated, IV magnesium
sulphate for seizures.
Eclampsia\: de
least two of the following features within 24 hours of the seizure\: hypertension, proteinuria, thrombocytopenia, raised AST.
If this develops it is an emergency and requires early IV magnesium sulphate.
Complications\: multi-organ dysfunction, cardiovascular events, placental abruption, eclampsia, HELLP syndrome
(haemolysis, elevated liver enzymes, low platelets).
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A comprehensive topic overview

Introduction

Pre-eclampsia is a multisystem syndrome, developing after 20 weeks of pregnancy. It is characterised by d e n o v o
hypertension which co-exists with one or more of the following clinical features\:
Proteinuria
Maternal dysfunction
Uteroplacental dysfunction
Hypertension may also develop after delivery but typically resolves by 6 weeks postpartum.
Pre-eclampsia is common, occurring in 2-8% of pregnancies.
1
Around 0.5% of pregnant women can develop severe pre-eclampsia which can be life-threatening for both the mother
and baby.
2
Severe pre-eclampsia can progress to eclampsia (1 in 4000 pregnancies), a complication resulting in maternal seizures.
2
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Aetiology

The underlying pathophysiology of pre-eclampsia is poorly understood. It is thought to be due to abnormal placentation
or maternal microvascular disease. Poor perfusion of the placenta results in oxidative stress and the release of pro-
in
results in the typical clinical features of pre-eclampsia\:
Oedema and proteinuria\: due to increased capillary permeability and movement of
Hypertension and end-organ damage (e.g. kidneys, liver)\: systemic vasoconstriction occurs secondary to the release of
vasoconstrictive factors.

Risk factors

The risk factors for pre-eclampsia are shown in table 1.
4
Table 1. Pre-eclampsia risk factors.
High risk Moderate risk
Chronic hypertension
Hypertensive disease in a previous
pregnancy
Type I or type II diabetes mellitus
Chronic kidney disease
Autoimmune disease\:
Anti-phospholipid syndrome
Systemic lupus erythematous
Aged 40 years or over
First pregnancy
Pregnancy interval >10 years
Multiple pregnancy
2
Pre-pregnancy obesity (BMI >35kg/m )
Family history of pre-eclampsia (
degree relative)
The risk of adverse maternal and fetal outcomes is increased if pre-eclampsia develops early, before 33 weeks gestation,
or at any gestation in those with additional risk factors.

Clinical features

History

Patients with pre-eclampsia often have no symptoms.
However, symptoms of pre-eclampsia may include\:
Headache
Visual disturbance\: such as blurring or
Swelling of the arms, legs and face
Nausea and vomiting
Abdominal pain
Reduced urine output

Clinical examination

Clinical signs of pre-eclampsia may include\:
Hypertension
Oedema\: typically in the peripheries and face
Epigastric/right upper quadrant tenderness
Hyper-re
Papilloedema
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Di

It is important to di
Chronic hypertension\: hypertension that occurs before 20 weeks gestation or persists after 12 weeks postpartum.
Gestational hypertension\: hypertension that occurs after 20 weeks gestation that develops without any co-existing
complications.
Pre-eclampsia superimposed on chronic hypertension\: hypertension that already exists but worsens after 20 weeks
gestation alongside the development of co-existing complications.

Investigations

Antenatal screening is used to detect pre-eclampsia at an early stage to allow appropriate management to prevent
adverse outcomes. Antenatal appointments include assessment of blood pressure, a urine dipstick test to identify
proteinuria (as well as signs of infection) and fetal heart auscultation.

Laboratory investigations

Speci
FBC\: low platelet count may suggest HELLP syndrome (see complications).
U&Es\: raised urea, raised creatinine and low eGFR indicate renal impairment.
LFTs\: raised ALT or AST indicate liver dysfunction.
Clotting pro
Placental growth factor (PIGF) supports trophoblastic growth and therefore has a role in placental angiogenesis. A blood
test measuring PIGF levels can be used to aid diagnosis in pre-eclampsia, particularly in patients with chronic or gestational
hypertension. Elevated levels of PIGF suggest that pre-eclampsia is unlikely to be present. However, low PIGF levels only
indicate, but do not con

Diagnostic criteria

The diagnostic criteria for pre-eclampsia are as follows\:
Hypertension\: blood pressure of ≥140mmHg systolic or ≥90mmHg diastolic.
Proteinuria\: ≥300 mg protein in a 24-hour urine collection, a urine protein/creatinine ratio ≥30 mg/mmol or two readings
of at least ++ protein on urinary dipstick analysis.
4
Maternal organ dysfunction\: liver involvement, renal insu
thrombocytopenia, DIC) and neurological involvement (e.g. visual disturbance).
Uteroplacental dysfunction\: intrauterine growth restriction and stillbirth.

Management

Pre-eclampsia typically progresses throughout pregnancy and only resolves after delivery. As a result, management
focuses on monitoring progression and managing risk factors until delivery is possible.

Monitoring

Monitoring of the patient's health involves\:
Regular blood pressure assessment
Regular screening for proteinuria
Regular blood tests including FBC, U&Es and LFTs
Regular fetal monitoring is also required for all patients with pre-eclampsia including\:
4
Cardiotocography\: assessment of the fetal heartbeat.
Ultrasound\: assessment of fetal growth and amniotic
Umbilical artery Doppler velocimetry\: assessment of placental and fetal circulation.
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Unless clinically indicated, only the latter two should be repeated regularly throughout pregnancy to monitor fetal
development, with monitoring frequency tailored to the severity of pre-eclampsia.

Medical management

All women with pre-eclampsia and a pre-existing chronic medical condition should have a medication review to optimise
their treatment.
Aspirin is thought to delay or prevent the onset of pre-eclampsia by inhibiting the in
Aspirin (75-150mg once daily) should be prescribed from 12 weeks gestation until delivery for patients with one high-risk
factor or two moderate risk factors.
4
Antihypertensives are key to reducing cardiovascular risk, particularly stroke risk in patients with pre-eclampsia. They
should be started at diagnosis with an aim of reducing blood pressure to 135/85mmHg and should be continued up to 6-12
weeks postpartum. Labetalol is a
unsuitable. Nifedipine is
receptor blockers and thiazide diuretics are contraindicated in pregnancy.
4
Venous thromboembolism (VTE) prophylaxis is required due to an increased risk of VTE development in pre-eclampsia
patients, particularly during hospital admission. Low molecular weight heparin can be used alongside physical measures
such as anti-embolism stockings.

Severe pre-eclampsia

Severe pre-eclampsia is de≥160mmHg systolic or ≥110mmHg diastolic and requires hospital
admission.
On admission, the fullPIERS (Preeclampsia Integrated Estimate of Risk) and PREP-S (Prediction model for Risks of
complications in Early-onset Preeclampsia - Survival analysis model) risk scores can be used to calculate the risk of
adverse maternal outcomes within 48 hours although the PREP-S score should not be used after 34 weeks gestation.
4
Both scores take into consideration gestational age and clinical
5 6
Management of severe pre-eclampsia should be individualised. Early delivery may be considered, depending on
gestational age and other factors such as\:
Severity of pre-eclampsia
Speed of progression
Inability to control blood pressure
Presence of complications
Compromised fetal wellbeing

Complications

Maternal complications of pre-eclampsia include\:
Multi-organ dysfunction\: with progressive worsening to multi-organ failure.
Cardiovascular complications\: particularly major events such as myocardial infarction and stroke.
Placental abruption.
Eclampsia
HELLP syndrome

Eclampsia

Eclampsia is de
least two of the following features within 24 hours of the seizure\:
7
Hypertension
Proteinuria
Thrombocytopenia
Raised AST
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Eclampsia develops in approximately 1 in 4000 pregnant women and has a high mortality rate (death in 1 in 50 women and
1 in 14 unborn babies).
2
If eclampsia develops, it is considered an obstetric emergency requiring hospital admission. Treatment should include early
delivery if possible and intravenous magnesium sulphate to treat the mother’s seizures and prevent reoccurrence. If
considering early delivery, corticosteroids should be administered to accelerate fetal lung maturation if less than 34 weeks
gestation.

HELLP syndrome

HELLP syndrome occurs in 10-20% of women with severe pre-eclampsia.
8
HELLP syndrome develops as a result of endothelial damage and consequent thrombi formation, associated with pre-
eclampsia. HELLP is an acronym which describes the characteristic features of the syndrome\:
Haemolysis\: red blood cells become damaged by the abnormal endothelium, resulting in microangiopathic haemolytic
anaemia.
Elevated Liver enzymes\: raised ALT and/or AST can occur due to hepatic sinusoid obstruction by
9
Low Platelets\: platelet levels drop below 150 x10 /L due to platelet consumption as a result of thrombi formation.
A blood
Early detection and aggressive management with intravenous magnesium sulphate, antihypertensives, blood
products and timely delivery reduces disease progression and can help prevent adverse outcomes.

References

NHS.uk. Pre-eclampsia. Published in 2018. Available from\: [LINK]
Royal College of Obstetricians & Gynaecologists. P r e-e c l a m p s i a . Published in 2012. Available from\: [LINK]
Roberts, J. P a t h o p h y s i o l o g y o f i s c h e m i c p l a c e n t a l d i s e a s e . Published in 2014. Available from\: [LINK]
NICE. H y p e r t e n s i o n i n p r e g n a n c y \: d i a g n o s i s a n d m a n a g e m e n t . Published in 2019. Available from\: [LINK]
Evidencio. P r e p-S \: R i s k o f c o m p l i c a t i o n s i n e a r l y-o n s e t p r e-e c l a m p s i a . Published in 2015. Available from\: [LINK]
Evidencio. f u l l P I E R S \: P r e-e c l a m p s i a i n t e g r a t e d e s t i m a t e o f r i s k . Published in 2015. Available from\: [LINK]
Douglas, KA., Redman CWG. E c l a m p s i a i n t h e U n i t e d K i n g d o m . Published in 1994. Available from\: [LINK]
Haram, K., Svendsen, Einar., Abildgaard, U. T h e H E L L P s y n d r o m e \: C l i n i c a l i s s u e s a n d m a n a g e m e n t . A R e v i e w . Published in
2009. Available from\: [LINK]

Reviewer

Dr Farah Shakeel
Consultant in Obstetrics & Gynaecology

Related notes

Amniotic Fluid Embolism
Antenatal Screening for Down’s Syndrome
Antepartum Haemorrhage (APH)
Breech Presentation
Caesarean Section
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Contents

Introduction
Aetiology
Risk factors
Clinical features
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