Hypertension in pregnancy Flashcards by Emily Ong

Describe the changes in blood pressure in pregnancy

¥ Blood pressure (BP) proportional to systemic vascular resistance and cardiac output
¥ Pregnancy Vasodilatation
¥ BP falls in early pregnancy
¥ Nadir reached at 22-24 weeks (lowest point)
¥ Steady rise until Term
¥ BP falls after delivery but subsequently rises and peaks at day 3-4 P/N

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what is the classification of hypertension in pregnancy?

¥ ≥140/90 mmHg on 2 occasions
¥ Diastolic BP >110 mmHg
¥ ACOG - >30/15 mmHg compared to booking BP

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What 3 different ways can hypertension present in pregnancy?

pre-existing hypertension
pregnancy induced hypertension
Pre-eclampsia

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Pre-existing hypertension:

what is this?
what is important to consider?
what does this increase the risk of?

This is:

HTN at booking or <20wks
HTN >3mths of delivery

Consider:
-secondary causes e.g. renal/cardiac, cushing’s, conn’s, phaeochromocytoma

Risks:

PET
IUGR
Abruption

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What is pregnancy induced hypertension?

New hypertension > 20wks without signif. Proteinuria and resolves within 6months of delivery

¥ No proteinuria or other features of pre-eclampsia
¥ Better outcomes than pre-eclampsia
¥ 15% progression to pre-eclampsia - depends on gestation
¥ Rate of recurrence is high

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What is pre-eclampsia? what are the three criteria?

This is a pregnancy-specific multi-system disorder with unpredictabl, variable and widespread manifestations

Hypertension
Proteinuria (≥0.3g/l or ≥0.3g/24h)
Oedema

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what is the pathogenesis of pre-eclampsia?

¥ Genetic predisposition
¥ Stage 1 - abnormal placental perfusion
¥ Stage 2 - maternal syndrome

¥ Abnormal placentation and trophoblast invasion failure of normal vascular remodelling
¥ Spiral arteries fail to adapt to become high capacitance, low resistance vessels
¥ Placental ischaemia widespread endothelial damage and dysfunction
¥ Mechanism unclear (??oxidative stress / PGI2 : TXA2 imbalance / NO)
¥ inc. Endothelial Activation
¥ inc. Capillary Permeability
¥ inc. Expression of CAM
¥ inc. Prothrombotic Factors
¥ inc. Platelet aggregration

VASOCONSTRICTION

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How does Pre eclampsia effects the CNS? 6

¥	Eclampsia
¥	Hypertensive encephalopathy
¥	Intracranial haemorrhage
¥	Cerebral Oedema
¥	Cortical Blindness
¥	Cranial Nerve Palsy

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How does Pre eclampsia affect the renal system?

¥ GFR

¥ Proteinuria

¥ serum uric acid (also placental ischaemia)

¥ creatinine / potassium / urea

¥ Oliguria /anuria

¥ Acute renal failure

acute tubular necrosis
renal cortical necrosis

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How does Pre eclampsia affect the liver?

¥ Epigastric/ RUQ pain

¥ Abnormal liver enzymes

¥ Hepatic capsule rupture

¥ HELLP Syndrome
Haemolysis, Elevated Liver Enzymes, Low Platelets
(microvascular endothelial activation and cell injury)

¥ high morbidity/ mortality

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How does Pre eclampsia affect the haematological system?

¥	decreased `Plasma Volume
¥	Haemo-concentration
¥	Thrombocytopenia
¥	Haemolysis
Disseminated Intravascular Coagulation

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How does Pre eclampsia cause cardi/pulmonary disease?

¥	Pulmonary oedema leads to ARDS
¥	iatrogenic
¥	disorder related
¥	Pulmonary Embolus
High mortality

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What can the placental disease of Pre eclampsia lead to?

Intrauterine growth restriction
Placental abruption
Intrauterine death

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What are the symptoms of pre-eclampsia? 6

¥	Headache 
¥	Visual disturbance
¥	Epigastric / RUQ pain
¥	Nausea / vomiting
¥	Rapidly progressive oedema
¥	Considerable variation in timing, progression and order of symptoms

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What are the signs seen in pre-eclampsia? 8

¥	Hypertension
¥	Proteinuria
¥	Oedema
¥	Abdominal tenderness
¥	Disorientation
¥	SGA
¥	IUD
¥	Hyper-reflexia / involuntary movements / clonus

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What investigations are carried out for Pre eclampsia ? 10

¥	Urea &amp; Electrolytes
¥	Serum Urate
¥	Liver Function Tests
¥	Full Blood Count
¥	Coagulation Screen
¥	UPCR
¥	CTG
¥	Ultrasound - biometry, 
¥	AFI, Doppler

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What are the risk factors for 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 PET (7X)
¥	Molar Pregnancy / Triploidy
¥	medical risk factors
(Multiparous women develop more severe disease)

What are the medical risk factors for Pre eclampsia ? 5

¥	Pre-existing renal disease
¥	Pre-existing hypertension
¥	Diabetes Mellitus
¥	Connective Tissue Disease
¥	Thrombophilias (congenital / acquired)

How is Pre eclampsia screened for/assessed at the booking appointment?

¥ Assess risk at booking – risk factors for pre-eclampsia = aspirin
¥ Then surveillance (scans/BP monitoring/urine testing)
¥ Hypertension < 20 weeks - look for secondary cause
Antenatal screening – BP/urine

How is Pre eclampsia managed antenatally?

¥ Treat hypertension

¥ Follow ups in MDAU PIH can be managed as o/p in day care unit

How is Pre eclampsia managed in labour?

¥ Maternal & fetal surveillance
¥ Timing of Delivery – most deliver at 37 weeks vaginally if pre-eclampsia
¥ Stabilize, treat hypertensions, prevent convulsions, deliver

When is a woman with pre-eclampsia referred to the antenatal day care unit? 4

BP 140/90 or more
(++)proteinuria
oedema
symptoms - esp persistent headache

When is a woman admitted for Pre eclampsia ? 6

BP >170/110 OR >140/90 with (++) proteinuria
Significant symptoms - headache / visual disturbance / abdominal pain
Abnormal biochemistry
Significant proteinuria - UPCR >30mg/mmol
Need for antihypertensive therapy
Signs of fetal compromise

What is involved with inpatient assessment of Pre eclampsia ?

¥	Blood Pressure - 4 hourly
¥	Urinalysis - daily
¥	Input / output fluid balance chart
¥	UPCR - if proteinuria on urinalysis
¥	Bloods - FBC, U&amp;Es, Urate, LFTs. Minimum X2 per week

What is involved with fetal surveillance in Pre eclampsia ?

``` ¥ Fetal Movements ¥ CTG - daily ¥ Ultrasound -Biometry -Amniotic Fluid Index -Umbilical Artery Doppler ```

When is hypertension treated in pregnancy?

Treat regardless of aetiology With MAP ≥150 mmHg there is significant risk of cerebral haemorrhage: ¥ Most treat if BP ≥150/100 mmHg (aim for <150/80-100 BP) ¥ If target organ damage aim for BP <140/90 ¥ If less than 140/90 or 130/90 – reduce dose ¥ BP ≥ 170/110 mmHg requires immediate Rx (Control of blood pressure does not reduce the risk of developing pre-eclampsia)

What does every woman with pre-eclampsia recieve?

magnesium sulphate to prevent siezures

What 4 drugs are used for hypertension in pregnancy?

- Methyldopa - labetalol - nifedipine SR - Hydralazine

Methyldopa: - mode of action - starting dose - max. dose - contraindication - breast feed?

mode of action: -centrally acting alpha agonist Starting dose: -250mg BD max. dose: - 1gram TDS Contraindication: -depression breast feed? -YES

Labetalol oral or IV: - mode of action - starting dose - max. dose - contraindication - breast feed?

Mode action: -alpha and beta blocker Starting dose: -100mg BD Max dose: -600mg qid contraindications: -asthma Breastfeed: yes

Nifedipine SR oral : - mode of action - starting dose - max. dose - contraindication - breast feed?

mode of action: -Ca channel blocker - starting dose: - 10mg BD - max. dose: - 40mg BD - contraindication: - none -breast feed? yes

Hydralazine IV: - mode of action - starting dose - max. dose - contraindication - breast feed?

Action: -vasodilator Starting dose: -25mg tds Max dose: -75mg QID Contrai. - none Breast feed: -yes

What anti-HTN drugs are avoided in pregnancy?

Diuretics/ACE-I

When is the baby delivered in pre-eclampsia?

¥ The only cure for pre-eclampsia is delivery ¥ Mother must be stabilised before delivery ¥ Consider expectant management if pre-term ¥ Most women delivered within 2 weeks of diagnosis

What are 6 indications for delivery?

``` ¥ Term gestation ¥ Inability to control BP ¥ Rapidly deteriorating biochemistry / haematology ¥ Eclampsia ¥ Other Crisis ¥ Fetal Compromise - REDF, abnormal CTG ```

What crisis exists in pre-eclampsia? 9

``` ¥ Eclampsia ¥ HELLP syndrome ¥ Pulmonary Oedema ¥ Placental Abruption ¥ Cerebral Haemorrhage ¥ Cortical Blindness ¥ DIC ¥ Acute Renal Failure ¥ Hepatic Rupture ```

What is eclampsia?

Tonic-clonic (grand mal) seizure occuring with features of pre-eclampsia ¥ >1/3 will have seizure before onset of hypertension / proteinuria ¥ Ante-partum (38%) / Intra-partum (16%) / post-partum (44%) ¥ More common in teenagers ¥ Associated with ischaemia / vasospasm

What is the management of severe PET or eclampsia?

¥ Control BP: IV labetalol/IV hydralazine ¥ Stop / Prevent Seizures ¥ Fluid Balance ¥ Delivery

Describe the prevention of siezures in PET?

Magnesium sulfate: Loading dose: 4g IV over 5 minutes Maintenance dose:IV infusion 1g/h If further seizures administer 2g Mg SO4 If persistent seizures consider diazepam 10mg IV

Describe fluid balance in PET?

¥ Main cause of death = pulmonary oedema (Capillary leak / fluid overload / cardiac failure) ¥ Oliguria in 30%. Does not require intervention ¥ Any doubts about renal function urine osmolality ¥ Fluid challenges are potentially dangerous ¥ Safer to run a patient “dry” - 80 ml/

Delivery in PET: - aim for what delivery? - what is used for anaesthesia - what is used to monitor baby? - what is avoided and cautioned?

``` ¥ Aim for vaginal delivery if possible ¥ Control BP ¥ Epidural anaesthesia ¥ Continuous electronic fetal monitoring ¥ Avoid ergometrine ¥ Caution with iv fluids ```

When is low dose aspirin used in the prevention of PET?

¥ Aspirin - inhibits cyclo-oxygenase prevents TXA2 synthesis ¥ 75mg Aspirin 15% reduction in PET (NNT=90) ¥ May be more beneficial in preventing severe early onset pre-eclampsia (MRC CLASP Trial) ¥ Safe ¥ Used for high risk women - Renal, DM, APS, Multiple risk factors, previous PET ¥ Commence before 12 weeks (NICE Aug 2010)