Hypertensive disorders in pregnancy Flashcards
What is the pattern of blood pressure during pregnancy?
It falls in the second trimester by around 30/15mmHg because of reduced vascular resistance.
What happens to protein excretion during pregnancy?
It is increased, but in the absence of any renal disease is less than 0.3g/24hours.
What is the definition of pregnancy induced hypertension? What are the conditions which cause it?
Any increase in blood pressure over 140/90mmHg after 20 weeks gestation - can be pre-eclampsia or transient hypertension.
How do you generally differentiate between pre-eclampsia and gestational hypertension? Why is this difficult to rely on?
Pre-eclampsia has proteinuria whereas gestational hypertension does not.
It is difficult to rely on because occasionally proteinuria is absent in pre-eclampsia, especially in early disease so it is difficult to distinguish.
How is pre-eclampsia cured?
Delivery of the baby.
What is the definition of pre-eclampsia?
Pre-eclampsia is a multisystem syndrome that usually manifests as new hypertension after 20 weeks with significant proteinuria.
What are the 2 types of pre-eclampsia?
Early-onset: causes complications before 34 weeks. Typically the foetal growth is restricted.
Late-onset: manifests later in gestation (>34 weeks) and is not usually associated with growth restriction, although foetal death or damage may also occur.
What is the pathophysiological mechanism of pre-eclampsia?
- Poor foetal perfusion. In normal pregnancy the trophoblastic invasion of spiral arterioles leads to vasodilatation of vessel walls to allow adequate placental perfusion.
This is incomplete in early-onset pre-eclampsia, causing oxidative stress. There is therefore high resistance flow in the spiral uterine arteries.
In late-onset pre-eclampsia, as growth of an apparently normal placental reaches its limits, inter-villous perfusion may reduce, perhaps because terminals become overcrowded, also causing oxidative stress. - Both mechanisms cause the oxidatively stressed placenta to oversecrete proteins that regulate angiogenic balance.
Hypertension –> widespread endothelial cell damage –> vasoconstriction, increased vascular permeability and clotting dysfunction.
What is severe pre-eclampsia?
Pre-eclampsia with severe hypertension and/or with symptoms, and/or biochemical and/or haematological impairment.
What is given to women deemed at risk of pre-eclampsia?
Low-dose aspirin.
What are the risk factors/indication for prophylactic treatment for pre-eclampsia?
Any one of:
- Previous hypertensive disease in pregnancy
- Renal impairment
- Chronic hypertension
- Autoimmune disease such as SLE or antiphospholipid syndrome
- Diabetes (type 1 or 2)
Any 2 of:
- Over 40 years old
- Nulliparous (more common in nulliparous than multiparous women)
- Over 10 years since last child
- BMI > 35
- Family history of pre-eclampsia
- Multiple pregnancy (twins)
How can you tell the difference between normal pregnancy oedema and pre-eclamptic oedema?
In pre-eclampsia it may be massive, not postural or of sudden onset.
There is also generally hypertension and proteinuria which can be tested for.
How long does it take for delivery to cure pre-eclampsia?
Up to 24 hours
What are the complications of pre-eclampsia which require delivery whatever the gestation?
Eclampsia - grand mal seizures, probably resulting from cerebrovascular vasospasm.
Cerebrovascular haemorrhage - results from a failure of cerebral blood flow auto-regulation at mean arterial pressure of above 140/90mmHg - control of hypertension should prevent this.
Liver failure - HELLP syndrome. Haemolysis, elevated liver enzymes and low platelets.
Renal failure
Pulmonary oedema
What is the treatment for eclampsia?
Magnesium sulfate
