Hypertension in pregnancy Flashcards
What is the most common cause of iatrogenic prematurity?
Pre-eclampsia
What are the CVS system changes in pregnancy?
- Plasma volume increases by 45%
- Cardiac output increases by 30-50%
- Stroke volume increases by 25%
- Heart rate increases by 15-25%
- Peripheral vascular resistance decreases by 15-20%
What is the definition of hypertension?
>140/90mmHg on 2 occasions
>160/mmHg once
(ACOG >30/15mmHg compared to first trimester BP)
What are the three variations of hypertension in pregnancy?
- pre-existing hypertension
- pregnancy induced hypertension (PIH)
- pre-eclampsia
When is pre-existing hypertension likely
When hypertension discovered early in pregnancy
When is pre-existing hypertension a retrospective diagnosis?
If BP has not returned to nromal within 3 months of delivery
What could be the secondary causes of pre-existing hypertension?
- renal/cardiac
- cushings
- conn’s
- phaeochromocytoma
What are the risks of pre-existing hypertension?
PET (x2)
IUGR
Abruption
What is PIH?
Pregnancy induced hypertension
- happens in second half of pregnancy and resolves within 6/52 of delivery
In PIH there is no ______ or other features of ___-_____, however __% progress to pre-eclampsia
In PIH there is no proteinuria or other features of pre-eclampsia, however __% progress to pre-eclampsia
What is pre-eclampsia?
- hypertension
- proteinuria (>0.3g/l or >0.3g/24hr)
- oedema
Pregnancy multi-system disorder with unpredictable, widespread manifestations.
Describe the presentation of pre-eclampsia
May be asymptomatic at first presentation
Then diffuse vascular and endothelial dysfunction, widespread circulatory disturbance
When is pre-eclapmsia classed as early or late?
> 34 weeks
What is the pathogenesis of pre-eclampsia?
- genetic/environmental predisposition
- stage 1- abnormal placental perfusion
- placental ischaemia
- stage 2- maternal syndrome
- an anti-angiogenic state associated with endothelial dysfunction
What are genetic and environmental factors though to do that cause pre-eclampsia?
Create conditions leading to defective deep placentation; the injured placenta then releases factors into the maternal circulation that induce pre-eclapmsia
Describe the pathogenesis of abnormal placentation?
- Abnormal placentation and trophoblast invasion -> failure of normal vascular remodelling
- Spiral arteries fail to adapt to become high capacitance, low resistance vessels
- Placental ischaemia and widespread endothelial damage and dysfunction
- Mechanism unclear (??oxidative stress / PGI2: TXA2 imbalance / NO)
- Endothelial Activation causes;
- increased Capillary Permeability
- increased Expression of CAM
- increased Prothrombotic Factors
- increased Platelet aggregration
- Vasoconstriction
What maintains endothelial health in normal pregnancy?
VEGF and TGF-B1
What is excreted in excess in pre-eclampsia?
sFIt1 and sEng
- they antagonise VEGF and TGF-B1*
- sFit1 also antagonises PIGF*
What systems does pre-eclampsia affect?
- CNS
- Renal
- hepatic
- haematological
- pulmonary
- cardiovascular
- placental
Describe liver disease in pregnancy?
HELLP syndrome
Haemolysis, Elevated Liver Enzymes, Low Platelets
How might liver disease in pregnancy present?
- Epigastric/RUQ pain
- abnormal liver
- hepatic capsule rupture
Placental disease can cause;
f___ _____ r_____
_________ a________
and intrauterine _____
Placental disease can cause;
foetal growth restriction
placental abruption
and intrauterine death
What are the symptoms of pre-eclampsia?
- headache
- visual disturbance
- epigastric/RUQ pain
- nausea/volitting
- rapidly progressive oedema
What are the signs of pre-eclampsia?
- hypertension
- proteinuria
- oedema
- abdominal tenderness
- disortientation
- small for gestational age (SGA) fetus
- intrauterine fetal death
- hyper-reflexia/involuntary movements/clonus
What are the investigations for pre-eclapmsia?
- urea and electrolytes
- serum urate
- liver function tests
- full blood count
- coagulation screen
- urine- protein creatinine ratio
- cardiotocography
- ultrasound- foetal assessment
Describe the management of hypertension in pregnancy?
- assess risk at booking- identify risk factors
- hypertension <20 weeks- look for secondary cause
- antenatal screening- BP, urine, MUAD
- treat hypertension
- maternal & foetal surveillance
- timing of delivery
What are the risk factors for hypertension in pregnancy?
- maternal age (>40 years ->2x)
- maternal BMI (>30 -> 2x)
- family history
- parity (first pregnancy 2-3x)
- multiple pregnancy (twins 2x)
- previous PE (7x)
- birht interval >10 years (2x)
- molar pregnancy/triploidy
- multiparous women might develop more severe disease
What are the medical risk factors for hypertension?
- pre-existing renal disease
- pre-existing hypertension
- diabetes (pre-existing/gestational)
- connective tissue disease
- thrombophilias (congenital acquired)
How does aspirin work?
Inhibits cyclooxygenase -> prevents TXA2 synthesis
When is LDA used?
High risk women- renal, DM, aPS, multiple risk factors, previous PET
When should LDA be commenced and what dose?
Before 16 weeks
150mg
When should a hypertensive pregnant lady be admitted?
- BP >170/110 OR >140/90 with (++ proteinuria)
- Significant symptoms- headache/visual disturbance/abdominal pain
- abnormal biochemistry
- significant proteinuria >300mg/24hr
- need for antihypertensive therapy
- signs of fetal compromise
Describe inpatient assesement of hypertension
- blood pressure- 4 hourly
- urinalysis- daily
- input/output fluid balance chart
- urine PCR - proteinuria on urinalysis
- bloods- FBC, U&Es, Urate, LFTs, minimum X2 week
What is there significant risk of in MAP >150mmHg
Cerebral haemorrhage
What BP requires immediate Rx
>170/110mmHg
What should be the aim of treatment
Achieve BP for 140-150/90-100mmHg
Control of BP ______ reduced the risk of developing pre-eclampsia?
Control of BP doesn’t reduced the risk of developing pre-eclampsia
Describe treatment of hypertension
First line;
- methyldopa- centrally acting a agonist, start on 250mg bd, maximum 1g tds, contraindications : depression, safe for breastfeeding
- labetolol- a and b antagonist, start on 100mg bd, maximum 600mg qid, containdications : asthma, safe for breastfeeding
- nifedipine SR- Ca channel antagonist, start on 10mg bd, maximum 40mg bd, safe for breastfeeding
Second line
- hydralazine- vasodilator, start on 25mg tds, maximum 75mg qid, safe for breastfeeding
- doxazocin- a antagoinst, 1mg od, max 8mg bd, not safe in breastfeeding
What is done in foetal surveillance?
- fetal movements
- CTG-daily
- ultrasound
- biometry
- amniotic fluid index
- umbilical artery doppler
What are the indications for birth in maternal hypertension?
- term gestation
- inability to control BP
- rapidly deteriorating biochemistry/haematology
- eclampsia
- other crisis
- fetal compromise- abnormal US or CTG
What are the crises in pre-eclampsia
- eclampsia
- HELLP
- pulmonary oedema
- placental abruption
- cerebral haemorrhage
- cortical blindness
- DIC
- acute renal failure
- hepatic rupture
Describe eclampsia
- tonic-clonic (grand mal) seizure occuring with features of pre-eclampsia
What is the management of severe PET/eclampsia
- control BP
- stop/prevent seizures
- fluid balance
- delivery
What antihypertensives should be given in severe PET/eclampsia
IV labetolol
IV hydralazine
What is the seizure treatment/prophylaxis?
Magnesium sulphate
- Loading dose 4g IV over 5 minutes*
- Maintenance dose- IV infusion 1g/hr*
If further seizures administer 2g Mg SO4
If persistent seizures consider diazepam 10mg IV
What is the main cause of maternal death?
Pulmonary Oedema
What causes pulmonary oedema in mums?
Capillary Leak
Fluid overload
Cardiac Failure
What should be done if there is any doubts about renal function?
Urine osmolality
