[18] Pre-eclampsia Flashcards
What is pre-eclampsia?
Pregnancy induced hypertension in association with proteinuria (>0.3g in 24 hours)
Why is pre-eclampsia important?
It is relatively common but can become life-threatening for mother and fetus
What is severe pre-eclampsia?
BP of ≥160/110 mmHg and/or symptoms and/or biochemical and/or haematology impairment
What is eclampsia?
The occurence of one or more convulsions superimposed on pre-eclampsia
What % of pregnancies in the UK are affected by pre-eclampsia?
6%
How dangerous are severe pre-eclampsia and eclampsia?
They are the second most common cause of direct maternal death in the UK
What proportion of pregnancies are affected by severe pre-eclampsia?
5/1000
What proportion of pregnancies are affected by eclampsia?
5/10,000
What proportion of stillbirths with no congenital abnormalities occur in women with pre-eclampsia?
20%
What proportion of women with severe pre-eclampsia deliver before 36 weeks?
50%
What is the common thought of what causes pre-eclampsia?
Poor placental perfusion due to abnormal placentation
What happens in normal placentation?
The trophoblast invades the myometrium and the spiral arteries, destroying the tunica muscularis media, rendering spiral arteries dilated and unable to constrict.
What is the result of normal placentation?
Provides pregnancy with a high flow, low resistance circulation
How is the remodelling of spiral arteries different in pre-eclampsia?
They are incompletely re-modelled
What is the result of incomplete spiral artery re-modelling in pre-eclampsia?
Development of a high resistance, low-flow uteroplacental circulation develops as the constrictive muscular walls of the spiral arterioles is maintained
How does the high resistance, low flow uteroplacental circulationof pre-eclampsia affect BP?
Causes an inccrease
What other pathophysiological factors are caused by inadequate uteroplacental perfusion in pre-eclampsia?
Hypoxia and oxidative stress
What is caused by the raised BP, hypoxia and oxidative stress caused by pre-eclampsia?
Systemic inflammatory response and endothelial cell dysfunction (resulting in leaky blood vessels)
What factors put women at high risk of pre-eclampsia?
- Previous pre-eclampsia
- Previous eclampsia
- Previous hypertension in pregnancy
- Pre-existing hypertension
- Pre-existing CKD
- Pre-existing diabetes
- SLE
- Antiphospholipid syndrome
What factors put women at moderate risk of pre-eclampsia?
- 10 years or more since last pregnancy
- First pregnancy
- Age 40 or more
- BMI >35 at presentation
- Family history
- Multiple pregnancy
What criteria should be met to be diagnosed with pre-eclampsia?
- Hypertension
- Significant proteinuria
- > 20 weeks gestation
What is classified as hypertension fulfilling the criteria of pre-eclampsia?
BP >140/90 mmHg on 2 occasions >4 hours apart
What is classified as significant proteinuria, fulfilling the criteria of pre-eclampsia?
> 300mg protein in a 24 hour urine sample or >30mg/mmol urinary protein:creatinine
Is the presentation of pre-eclampsia the same in everyone?
No
Why should proteinuria and hypertension be checked for at every antenatal appointment?
Some people with pre-eclampsia are asymptomatic
What are some possible clinical features of pre-eclampsia?
- Headaches
- Visual disturbance
- Epigastric pain
- Sudden onset non-dependent odema
- Hyper-reflexia
What visual disturbances can occur in pre-eclampsia?
- Blurred or double vision
- Halos
- Flashing lights
Where do pre-eclampsia headaches usually occur?
Frontal
What BP range is mild pre-eclampsia?
140-149/90-99 mmHg
What BP range is moderate pre-eclampsia?
150-159/100-109 mmHg
What is severe pre-eclampsia?
> 160/100 mmHg AND proteinuria
OR
> 140/90mmHg, proteinuria and symptoms
What are the differentials for pre-eclampsia?
- Essential HTN
- Pregnancy induced HTN
- Eclampsia
What is essential HTN?
HTN prior to 20 weeks gestation
What is pregnancy induced HTN?
New onset HTN after 20 weeks without proteinuria
What is eclampsia?
Pre-eclampsia and seizures
What investigations should be done for pre-eclampsia?
- Urinalysis
- Blood tests
- Clotting studies
- 24 hour urine collection for protein quantification and creatinine clearance
- Assessment of fetus
What analysis should urine undergo in suspected pre-eclampsia if protein is present?
- Microscopy
- Culture
- Sensitivty
What blood tests should be ordered in assessment of pre-eclampsia?
- FBC
- LFT
- Renal function
- Serum urea
How should the fetus be assessed in suspected pre-eclampsia?
- Ultrasound assessment of fetal growth
- Volume of amniotic fluid
- Umbilical artery doppler
When should a woman with suspected pre-eclampsia be admitted straight to hospital?
- > 1+ protein OR
- >30mg/mmol spot urea:creatinine
Whys should women with certain protein or spot protein:creatine be admitted straight to hospital?
They are over the dividing line between minimal and significant risk to mother and baby
What are the aims of management in pre-eclampsia?
- Prevent development of eclampsia
- Minimise the risk of complications for mother and fetus
What plays a large part in management of pre-eclampsia?
Monitoring of maternal and fetal wellbeing
How can maternal and fetal wellbeing monitoring be achieved in pre-eclampsia?
- Regular BP measurements
- Urinalysis
- Blood tests
- Fetal growth scans
- Cardiotocography
As a rule what is the degree and frequency of monitoring in pre-eclampsia correlated with?
Severity of disease
What are some other potential management points for pre-eclampsia?
- VTE prevention
- Anti-hypertensives
- Delivery
Why is VTE prevention an important consideration in the management of pre-eclampsia?
Most women are managed as inpatients and require fluid management and VTE prophylaxis
What is the most commonly used agent for VTE prevention in pre-eclampsia?
LMWH
Why are anti-hypertensives used in pre-eclampsia?
Reduce the risk of maternal haemorrhagic stroke
Do antihypertensives help to alter the course of pre-eclampsia?
No
What is the only definitive cure for pre-eclampsia?
Delivery of the baby
What should influence the decision of how and when to deliver in pre-eclampsia?
Health of mother and fetus
Who does prolonging pregnancy in pre-eclampsia benefit?
Only the fetus
What should be given if delivery is to occur before 35 weeks gestation for pre-eclampsia?
IM steroids
Why are IM steroids used for early delivery in pre-eclampsia?
to aid development of fetal lungs
When does pre-eclampsia resolve?
After delivery of the placenta
How long should the mother be monitored for post-partum in pre-eclampsia?
24 hours
Why should the mother have monitoring for 24 hours post-partum in pre-eclampsia?
They are still at risk of having eclamptic seizures
When can women with pre-eclampsia be considered safe after delivery?
Day 5
How long should BP be monitored for after delivery in pre-eclampsia?
Daily for first 2 days then at least once 3-5 days post-partum
Should women stay on anti-hypertensives after pre-eclampsia?
The need should be re-assessed
What should women be warned of in the future following pre-eclampsia?
Risk of developing pre-eclampsia or gestational induced hypertension in future pregnancies
What feature of pre-eclampsia is associated with a poorer prognosis for the development of complications?
Onset before 34 weeks
What are the maternal complications of pre-eclampsia?
- HELLP syndrome
- Eclampsia
- AKI
- DIC
- ARDS
- Post-partum hypertension
- Cerebrovascular damage
What are the major fetal complications of pre-eclampsia?
- Prematurity
- IUGR
- Placental abruption
- Intrauterine fetal death
How can pre-eclampsia and its complications be prevented?
- Identify women with known risk factors at booking
- Early recognition and action against symptoms
- Antiplatelet agents
- Calcium supplementation in pregnancy
What antiplatelet agent is often used to reduce the risk of pre-eclampsia?
Low dose aspirin
What is NICE’s recommended dose of aspirin for prevention of pre-eclampsia?
75mg from 12 weeks to women at high risk or 2 moderate risk factors