Hypertension in Pregnancy Flashcards
What % of all pregnancies does hypertension affect?
10-15%
What is a primigravida woman?
A woman who is pregnant for the first time
What % of primigravida women are affected by mild pre-eclampsia?
10%
What % of primigravida women are affected by sever pre-eclampsia?
1%
What % of women with eclampsia will die?
<1%
What is pre-eclampsia the commonest cause of?
Iatrogenic prematurity
Up to what % of antenatal hospital admissions are due to hypertension?
25%
Hypertension results in __% of antenatal hospital admissions?
25%
Peripheral vascular resistance _________ by 15-20% during pregnancy
DECREASES
CVP is _________ during pregnancy
UNCHANGED
What is CVP?
Central vascular resistance - resistance in the vena cava
During what trimester do most cardiovascular changes occur?
1st
What is BP proportional to?
Systemic vascular resistance and cardiac output.
In pregnancy, what happens to blood vessels?
They vasodilate
What happens to BP in early pregnancy?
It FALLS
Why does BP fall in early pregnancy?
It occurs because the circulation expands during pregnancy and hormonal changes cause the blood vessels to dilate, leading to a lowering of blood pressure.
The blood pressure begins to fall in early pregnancy and is usually at its lowest sometime in the middle of the second trimester.
When is Nadir reached (lowest point)?
At 22-24 weeks
After nadir, when the lowest BP is reached, what happens?
The BP slowly rises until term
What happens to BP after delivery?
Falls after delivery, but subsequently rises and peaks at day 3-4 P/N
What is hypertension in pregnancy defined as?
- ≥140/90 mmHg on 2 occasions
or - > 160/110 mmHg once
- (ACOG - >30/15 mmHg compared to first trimester BP)
What are the 3 categories of hypertension in pregnancy?
- Pre-existing hypertension.
- Pregnancy Induced Hypertension (PIH).
- Pre-eclampsia.
When is pre-existing hypertension diagnosed?
Before pregnancy obvs
When should you think pre-existing hypertension?
If there is hypertension in EARLY pregnancy
What are PET and PIH diseases of?
Second half of pregnancy
When may pre-existing hypertension be a retrospective diagnosis?
BP has not returned to normal within 3 months of delivery
List some causes of pre-existing hypertension.
Renal/cardiac, Cushing’s, Conn’s, Phaeochromocytoma
What are the risks for a pregnant woman with pre-existing hypertension?
PET (x2), IUGR and abruption.
When does the onset of PIH occur?
Second half of pregnancy
When will PIH resolve by?
6 weeks after pregnancy
How can PIH be differentiated from pre-eclampsia?
There is no proteinuria, or other features of pre-eclampsia.
What has better outcomes; PIH or pre-eclampsia?
PIH
What is the % progression of this to pre-eclampsia? What does this depend on?
15% - depends on gestation.
What is the rate of recurrence of PIH with subsequent pregnancies like?
High
What is pre-eclampsia classically defined by the presence of?
Hypertension \+ Proteinuria (≥0.3g/l or ≥0.3g/24h) \+ Oedema
If one of the 3 features of pre-eclampsia is not present, it can be ruled out as a diagnosis
FALSE
What is pre-eclampsia?
A pregnancy-specific multi-system disorder with unpredictable, variable and widespread manifestations.
Pre-eclampsia can be asymptomatic at time of first presentation
True
Pathologically, what does pre-eclampsia involve?
A diffuse vascular endothelial dysfunction and widespread circulatory disturbance.
Name 6 systems which pre-eclampsia may involve?
Renal. Hepatic. Cardiovascular. Haematology CNS. Placenta.
When does EARLY pre-eclampsia occur?
<34 weeks
How common is EARLY pre-eclampsia?
Uncommon – 12% of all pre-eclampsia.
In relation to the placenta, what is pre-eclampsia associated with?
Extensive villous and vascular lesions of the placenta.
Compare the risk of early pre-eclampsia to late pre-eclampsia.
Higher risk of maternal and foetal complications.
When does LATE pre-eclampsia occur?
> 34 weeks
What type of pre-eclampsia makes up the majority of pre-eclampsia?
LATE - around 88%
What effect does late pre-eclampsia have on the placenta?
Minimal placental lesions
Most deaths from pre-eclampsia occur when?
In late disease
What factors are thoughts to predispose someone to pre–eclampsia?
Genetic and environmental factors – thought to create conditions leading to defective deep placentation, with the injured placenta then releasing factors into the maternal circulation that induce pre-eclampsia
What are the 2 main causative factors in pre-eclampsia?
- Abnormal placental perfusion
2. Maternal syndrome
What is the 1st stage in the pathogenesis of pre-eclampsia?
Abnormal placental perfusion – placental ischaemia.
What is the 2nd stage in the pathogenesis of pre-eclampsia?
Maternal syndrome – an anti-angiogenic state associated with endothelial dysfunction
In pre-eclampsia, there is ________ blood flow in the ______ artery
- Reduced
2. Spiral
Outline how abnormal placentation can lead to pre-eclampsia.
Abnormal placentation and trophoblast invasion leads to failure of normal vascular remodelling.
Spiral arteries then fail to adapt to become high capacitance, low resistance vessels.
Placental ischaemia results in widespread endothelial damage and dysfunction
Endothelial Activation …..
- Capillary Permeability
- Expression of CAM
- Prothrombotic Factors
- Platelet aggregration
- Vasoconstriction
How can pre-eclampsia affect the CNS?
- Eclampsia.
- Hypertensive encephalopathy.
- Intracranial haemorrhage.
- Cerebral oedema.
- Cortical blindness.
- Cranial nerve palsy.
What renal affects may pre-eclampsia have?
- Decreased GFR.
- Proteinuria.
- Increased serum uric acid (also placental ischaemia).
- Increased creatinine/potassium/urea.
- Oliguria/anuria.
- Acute renal failure: acute tubular necrosis, renal cortical necrosis.
What signs/symptoms may be seen in liver disease caused by pre-eclampsia?
- Epigastric/RUQ pain.
- Abnormal liver enzymes.
- Hepatic capsule rupture.
What syndrome may pre-eclampsia affecting the liver result in?
HELLP Syndrome
- Haemolysis
- Elevated Liver Enzymes
- Low Platelets
(high morbidity/mortality)
What 3 things should ALWAYS be checked in someone with pre-eclampsia (if trying to find liver disease)?
- Renal function
- Liver function
- Platelets (fbc)
How may pre-eclampsia manifest haemotologically?
- Decreased volume.
- Haemo-concentration.
- Thrombocytopenia.
- Haemolysis.
- Disseminated intravascular coagulation.
How may pre-eclampsia cause ARDS?
Due to pulmonary oedema
How may pre-eclampsia affect the placenta?
- Feral growth restriction (FGR).
- Placental abruption.
- Intrauterine death.
What symptoms may pre-eclampsia present with?
- Headache.
- Visual disturbance.
- Epigastric/RUQ pain.
- Nausea/vomiting.
- Rapidly progressive oedema.
What signs may be present in pre-eclampsia?
- Hypertension.
- Proteinuria.
- Oedema.
- Abdominal tenderness.
- Disorientation.
- SGA.
- IUD.
- Hyper-reflexia/involuntary movements/clonus.
What is one of the first things to be elevated in pre-eclampsia?
Serum urate – either due to problems with the liver, or placental ischaemia.
What Ix’s should be carried out in pre-eclampsia?
- Urea & Electrolytes
- Serum Urate
- Liver Function Tests
- Full Blood Count
- Coagulation Screen
- Urine PCR
- CTG
- Ultrasound - fetal biometry, AFI, Doppler
When should risk of pre-eclampsia be assessed?
At booking
Hypertension in <20 weeks, what should be looked for?
Pre-existing cause
During an antenatal appointment, how is pre-eclampsia screened for (3 things)?
BP, urine, MUAD
What does MUAD look at? Why is this important when assessing a pregnant lady in the context of pre-eclampsia?
Blood flow to the uterus.
Tells us if change in the spiral arteries to the uterus has taken place.
What are the risk factors for the development of pre-eclampsia?
- Maternal age (>40 years - 2X)
- Maternal BMI (>30 - 2X)
- Family history (20-25% if mother affected, up to 40% if sister)
- Parity (first pregnancy 2-3X)
- Multiple pregnancy (Twins 2X)
- Previous PE (7X)
- Birth interval >10 years (2X)
- Molar Pregnancy / Triploidy
- Multiparous women develop more severe disease
What are the medical risk factors for the development of pre-eclampsia?
- Pre-existing renal disease
- Pre-existing hypertension
- Diabetes (pre-existing/gestational)
- Connective tissue disease
- Thrombophilias (congenital / acquired)
How does aspirin work?
It inhibits cyclo-oxygenase, preventing TXA2 synthesis.
What dose of aspirin is given in high risk women (of pre-eclampsia)?
75mg
It reduces PET by 15% (NNT = 90)
What is low dose aspirin useful in preventing?
Severe early onset pre-eclampsia
Who is aspirin given to?
High risk women in pregnancy – renal, DM, APS, multiple risk factors, previous PET
When should aspirin be started in high risk women?
Before 12 weeks
What is MUAD?
Materna uterine artery doppler
When should a pregnant lady be referred to AN DCU (antenatal day care unit)?
- BP - 140/90.
- (++) Proteinuria.
- Oedema.
- Symptoms – especially persistent headache.
When should you admit a pregnant lady to hospital? (6)
- BP >170/110 OR >140/90 with (++) proteinuria
- Significant symptoms - headache / visual disturbance / abdominal pain
- Abnormal biochemistry
- Significant proteinuria - >300mg / 24h
- Need for antihypertensive therapy
- Signs of fetal compromise
What inpatient assessment should be done for a pregnant lady with suspected pre-eclampsia?
- Blood Pressure - 4 hourly
- Urinalysis – daily
- Input / output fluid balance chart
- Urine PCR - if proteinuria on urinalysis
- Bloods - FBC, U&Es, Urate, LFTs. Minimum X2 per week (in CAP!)
Treat hypertension regardless of cause
TRUE
With MAP >= 150mmHg, what is there significant risk of?
cerebral haemorrhage
Most cases of hypertension should be treated if …..
> =150/100mmHg
What BP needs immediate Rx?
≥ 170/110 mmHg
What BP range should be aimed for in pregnancy?
140-150/90-100mmHg
What does controlling BP during pregnancy not reduce the risk of?
Risk of developing pre-eclampsia
What are the 3 first line treatments of hypertension in pregnancy?
- Methyldopa.
- Labetalol.
- Nifedipine.
What is the first line drug in treatment of hypertension in pregnancy?
Labetalol
Name 2, 2nd line anti-hypertensives used in pregnancy.
Hydralazine.
Doxazocin.
What 2 categories of anti-hypertensives should NEVER be used in pregnancy?
Diuretics and ACEI’s.
How can a foetus be monitored?
- Assessing fetal movements.
- Daily CTG.
- US– biometry, amniotic fluid index, umbilical artery doppler.
In what trimester is umbilical artery doppler done?
3rd trimester
How many umbilical arteries are there?
2
What happens in REDF?
Blood starts flowing back towards the baby - serious
What is the only cure for pre-eclampsia?
BIRTH
Before birth in a mother with pre-eclampsia, what must be done?
The mother must be stabilised
When do most women with pre-eclampsia deliver?
Within 2 weeks of the diagnosis
What are some indications for birth?
- Term gestation.
- Inability to control BP.
- Rapidly deteriorating biochemistry/haematology.
- Eclampsia.
- Other crisis.
- Fetal compromise – REDF, abnormal CTG.
What is eclampsia?
Tonic-clonic (grand mal) seizure occurring with features of pre-eclampsia.
When will >1/3 have a seizure in eclampsia?
Before the onset of hypertension/proteinuria
Who is eclampsia more common in?
Teenagers
What is eclampsia associated with (in relation to vascular problems)?
Ischaemia/vasospasm.
What are the 4 steps in the management of severe PET/eclampsia?
- Control BP.
- Stop/Prevent seizures.
- Fluid balance.
- Delivery.
What is given for treatment/prophylaxis of seizures ??
MAGNESIUM SULPHATE
What is the loading dose of magnesium sulphate in seizures?
4g IV over 5 mins
What is the maintenance dose of magnesium sulphate in seizures?
IV infusion 1g/h
What should you do if the patient has further seizures after giving magnesium sulphate?
Administer 2g Mg SO4
What should be considered if the patient has persistent seizures?
Diazepam 10mg IV.
What is the main cause of maternal death? How does this develop?
Pulmonary oedema – capillary leak leads to fluid overload, then cardiac failure.
In what % of cases is there oliguria? What is done for this?
30%.
Nothing – does not require intervention
If there is any doubts about renal function in a pregnant lady, what should be checked?
Urine osmolality
What are potentially dangerous when checking fluid balance? What is therefore safer?
Fluid challenges.
Safer to run a patient ‘dry’ – 80ml/h.
What kind of birth should be aimed for in hypertension?
Vaginal
What kind of anaesthesia may be used during labour in hypertension?
Epidural
What should be done continually during labour of someone with hypertension?
Electronic foetal monitoring
What should be avoided during labour in eclampsia?
Ergometrine (has hypertensive effects).
What should be used with caution during labour?
IV fluids.