Hypertension in PregnancyHypertension in Pregnancyfor Undergraduatesfor Undergraduates

Max Brinsmead MB BS PhDMax Brinsmead MB BS PhD

February 2015February 2015

This talkThis talk How to measure BPHow to measure BP When is a pregnant woman hypertensiveWhen is a pregnant woman hypertensive What is the Differential DiagnosisWhat is the Differential Diagnosis What tests are required and how do you What tests are required and how do you

interpret theminterpret them Risk factors for pre-eclampsiaRisk factors for pre-eclampsia Pathophysiology of pre eclampsiaPathophysiology of pre eclampsia How to manage the hypertensive gravidaHow to manage the hypertensive gravida Drugs to lower BP in pregnancyDrugs to lower BP in pregnancy

This talk(2)This talk(2)

When to deliverWhen to deliver Best practice intrapartum careBest practice intrapartum care Who requires an anticonvulsant?Who requires an anticonvulsant? What is the best drug for Eclampsia?What is the best drug for Eclampsia? Best practice postpartum careBest practice postpartum care Prognosis after pre-eclampsiaPrognosis after pre-eclampsia Can pre-eclampsia be prevented?Can pre-eclampsia be prevented?

How to Measure BP in a Pregnant WomanHow to Measure BP in a Pregnant Woman

o Automated machines not recommendedAutomated machines not recommendedo Unless calibrated against a mercury sphygmomanometer in Unless calibrated against a mercury sphygmomanometer in

the individual patientthe individual patient

Appropriate sized cuffAppropriate sized cuff Seated for 2 - 3 minutes with feet supportedSeated for 2 - 3 minutes with feet supported Both arms first visitBoth arms first visit Palpate systolic and go 20 mm higherPalpate systolic and go 20 mm higher Deflate slowly 2 mm every secDeflate slowly 2 mm every sec Use Korotkoff 5 (or 4 if 5 absent) for diastolicUse Korotkoff 5 (or 4 if 5 absent) for diastolic Repeated measures may be requiredRepeated measures may be required Ambulatory monitoring useful for White Coat Ambulatory monitoring useful for White Coat

HypertensionHypertension

When is a Pregnant Woman When is a Pregnant Woman Hypertensive?Hypertensive?

>140/90 on >one occasion>140/90 on >one occasion (Rise of >30 systolic or >15 diastolic)(Rise of >30 systolic or >15 diastolic)

Knowledge of prior BP very importantKnowledge of prior BP very important No longer accepted as a diagnostic pointNo longer accepted as a diagnostic point

Severe hypertension is >169 systolic Severe hypertension is >169 systolic and and oror diastolic >109 diastolic >109

Requires admission and urgent RxRequires admission and urgent Rx

(However, the diagnosis is more important (However, the diagnosis is more important than the actual level of BP).than the actual level of BP).

Differential Diagnosis of Hypertension Differential Diagnosis of Hypertension in Pregnancyin Pregnancy

Gestational HypertensionGestational Hypertension Sustained hypertension after 20w of pregnancy without any Sustained hypertension after 20w of pregnancy without any

other organ involvement. Returns to normal in 3mother organ involvement. Returns to normal in 3m

PreeclampsiaPreeclampsia Sustained hypertension after 20w of pregnancy with Sustained hypertension after 20w of pregnancy with

evidence of other organ involvement. Returns to normal in evidence of other organ involvement. Returns to normal in 3m3m

Chronic HypertensionChronic Hypertension Hypertensive before 20w. 95% is Essential Hypertension Hypertensive before 20w. 95% is Essential Hypertension

Includes “White Coat Hypertension”Includes “White Coat Hypertension”

Systems involved in PreeclampsiaSystems involved in Preeclampsia RenalRenal

Significant proteinuria Significant proteinuria S Creat >90 S Creat >90 OliguriaOliguria

HepaticHepatic Elevated transaminases Elevated transaminases Epigastric or RUQ painEpigastric or RUQ pain

HaematologicalHaematological Thrombocytopenia Thrombocytopenia HaemolysisHaemolysis DICDIC

CNSCNS Eclampsia or strokeEclampsia or stroke Hyperreflexia with sustained clonusHyperreflexia with sustained clonus Severe headache or visual disturbanceSevere headache or visual disturbance

CardiovascularCardiovascular Pulmonary oedemaPulmonary oedema

PlacentalPlacental IUGRIUGR AbruptionAbruption

Please notePlease note

I have not used the words “Pregnancy induced I have not used the words “Pregnancy induced Hypertension” or PIHHypertension” or PIH

No mention is made of oedemaNo mention is made of oedema

Proteinuria is the most common manifestation of Proteinuria is the most common manifestation of “other system involvement” “other system involvement”

Evidence for other organ involvement in Pre Evidence for other organ involvement in Pre eclampsia is a mix of symptoms, signs and testseclampsia is a mix of symptoms, signs and tests

Some rare causes of preeclampsia Some rare causes of preeclampsia before 20w before 20w

Hydatidiform moleHydatidiform mole

Fetal triploidy (with or without partial mole)Fetal triploidy (with or without partial mole)

Severe renal diseaseSevere renal disease

Lupus obstetric syndromeLupus obstetric syndrome

Renal Disease in PregnancyRenal Disease in Pregnancy

Responsible for about 5% of chronic hypertensionResponsible for about 5% of chronic hypertension

Causes include:Causes include: chronic or recurrent infectionchronic or recurrent infection glomerulonephritisglomerulonephritis renal artery stenosisrenal artery stenosis

Must be assessed by creatinine clearance (CC) Must be assessed by creatinine clearance (CC) which doubles in normal pregnancywhich doubles in normal pregnancy

When CC falls below 50% the prognosis for a When CC falls below 50% the prognosis for a pregnancy is very badpregnancy is very bad

Monitoring for superimposed pre eclampsia can Monitoring for superimposed pre eclampsia can be difficult if there is chronic proteinuriabe difficult if there is chronic proteinuria

Some rare causes of hypertensionSome rare causes of hypertension

Coarctation of the aortaCoarctation of the aortaSometimes the clue is to measure BP in both armsSometimes the clue is to measure BP in both armsThere is a systolic murmur that can be heard in the There is a systolic murmur that can be heard in the

backback

PhaeochromocytomaPhaeochromocytomaParoxysms of symptomatic hypertensionParoxysms of symptomatic hypertensionThe clue to diagnosis is to think of itThe clue to diagnosis is to think of itAssociated with high levels of catecholaminesAssociated with high levels of catecholamines

HyperaldosteronismHyperaldosteronismAlso known as Conn’s diseaseAlso known as Conn’s disease

Placental tissuePlacental tissueIn healthy pregnancies cytotrophoblast In healthy pregnancies cytotrophoblast

infiltrates the decidual portion of the uterine infiltrates the decidual portion of the uterine spiral arteriesspiral arteries

In order to increase maternal blood flow to the In order to increase maternal blood flow to the placentaplacenta

In patients destined to develop pre eclampsia In patients destined to develop pre eclampsia this fails to occurthis fails to occur

This results in placental hypoperfusionThis results in placental hypoperfusionThese changes occur at <16 weeks gestation These changes occur at <16 weeks gestation

but the pre eclampsia may not be manifest until but the pre eclampsia may not be manifest until much later in the pregnancymuch later in the pregnancy

Pathophysiology of Pre eclampsiaPathophysiology of Pre eclampsia

HypoperfusionHypoperfusion of the Placenta of the Placenta Becomes worse as pregnancy progresses Becomes worse as pregnancy progresses The abnormal uterine vasculature is unable to The abnormal uterine vasculature is unable to

accommodate the normal rise in blood flow to accommodate the normal rise in blood flow to the fetus/placenta that occurs with increasing the fetus/placenta that occurs with increasing gestational age. gestational age.

Late placental changes consistent with Late placental changes consistent with ischemia include atherosis (lipid-laden cells in ischemia include atherosis (lipid-laden cells in the wall arterioles), fibrinoid necrosis, the wall arterioles), fibrinoid necrosis, thrombosis, sclerotic narrowing of arterioles, thrombosis, sclerotic narrowing of arterioles, and placental infarction and placental infarction

Pathophysiology of Pre eclampsiaPathophysiology of Pre eclampsia

An ‘immunolgical’ response to pregnancyAn ‘immunolgical’ response to pregnancy ---in ‘at risk’ or predisposed women---in ‘at risk’ or predisposed women

A response to a conceptus whose genetic A response to a conceptus whose genetic material is 50% foreign (from the father)material is 50% foreign (from the father)

A failure of ‘Blocking Antibody’A failure of ‘Blocking Antibody’

This disease is still a mysteryThis disease is still a mystery

Pathophysiology WHY?Pathophysiology WHY?

Contracted intravascular volume of motherContracted intravascular volume of motherIn reality a failure to increase plasma volumeIn reality a failure to increase plasma volume

↑↑Sensitivity to pressure agentsSensitivity to pressure agentsLeaky capillariesLeaky capillariesReduced oncotic pressureReduced oncotic pressure

In part due to low serum albumenIn part due to low serum albumen

Poor placental reservePoor placental reserveA fetus at risk of hypoxia and deathA fetus at risk of hypoxia and death

Pathophysiology WHAT?Pathophysiology WHAT?

Tests for the Hypertensive GravidaTests for the Hypertensive Gravida Blood testsBlood tests

FBC - look at HB, Haematocrit and PlateletsFBC - look at HB, Haematocrit and Platelets UEC - look at Creatinine Should be < 0.07 (or 70)UEC - look at Creatinine Should be < 0.07 (or 70) URATE - equivalent to weeks of gestationURATE - equivalent to weeks of gestation Liver enzymes – AST & ALT should be <70. Ignore ALPLiver enzymes – AST & ALT should be <70. Ignore ALP

UUrine Tests rine Tests UMCS - exclude UTI and look for castsUMCS - exclude UTI and look for casts Protein:Creatinine ratio from spot test (>30 significant)Protein:Creatinine ratio from spot test (>30 significant) 24 hr protein excretion (>300 mg/day significant)24 hr protein excretion (>300 mg/day significant)

Assess fetal welfare by CTG & Scan for Assess fetal welfare by CTG & Scan for amniotic fluid volume & umbilical artery amniotic fluid volume & umbilical artery DopplersDopplers

Management of Hypertensive Management of Hypertensive GravidaGravida

Hospitalise if pre-eclampticHospitalise if pre-eclamptic Discharge if “just BP”Discharge if “just BP” Bed rest only when there is proteinuriaBed rest only when there is proteinuria Control BP to protect mother from severe Control BP to protect mother from severe

hypertensionhypertension Role of antihypertensive agents for mild & Role of antihypertensive agents for mild &

moderate chronic hypertension is still moderate chronic hypertension is still controversialcontroversial

Delivery will cure pre eclampsia and Delivery will cure pre eclampsia and gestational hypertensiongestational hypertension

Remember thromboprophylaxisRemember thromboprophylaxis

Drugs for Hypertension in Drugs for Hypertension in Pregnancy?Pregnancy?

AldometAldomet An old and safe drug An old and safe drug

Beta BlockersBeta Blockers Labetalol widely used in AustraliaLabetalol widely used in Australia Oxyprenalol also shown in RCT to be usefulOxyprenalol also shown in RCT to be useful

Ca channel blockersCa channel blockersNifedipineNifedipine

PrazosinPrazosin Relaxes pressor arteriolesRelaxes pressor arterioles

Drugs for Hypertension in Drugs for Hypertension in Pregnancy?Pregnancy?

Combination therapy of drugs from Combination therapy of drugs from different classes is possible e.g.different classes is possible e.g.Aldomet + Beta blocker + PrazosinAldomet + Beta blocker + Prazosin

Do not use…Do not use…Thiazide diuretics – reduce plasma volumeThiazide diuretics – reduce plasma volumeHighly selective beta blokers – cause IUGRHighly selective beta blokers – cause IUGRACE inhibitors – may cause IUFDACE inhibitors – may cause IUFD

Aim for BP 130 -150 systolic and 80 – Aim for BP 130 -150 systolic and 80 – 100 diastolic100 diastolic

Drugs for Acute Hypertension in Drugs for Acute Hypertension in PregnancyPregnancy

IV IV HydralazineHydralazine IV IV LabetalolLabetalol

Not available in AustraliaNot available in Australia NifedipineNifedipine tablets crushed and oral tablets crushed and oral

Repeat after 30 minRepeat after 30 min IV IV DiazoxideDiazoxide in small boluses in small boluses

Which Drug is Best for Eclampsia?Which Drug is Best for Eclampsia?

First aid is more important than drugsFirst aid is more important than drugs Protect from injuryProtect from injury Secure an airwaySecure an airway Administer oxygenAdminister oxygen Then secure IV accessThen secure IV access

IV MgSOIV MgSO4 loading dose Maintain by infusion IV Diazepam only for status eclampticus Monitor urine output, respirations, O2

saturation and deep tendon jerks

Who Requires Delivery?Who Requires Delivery?

Pre eclampsia >36 completed weeksPre eclampsia >36 completed weeks Uncontrollable hypertensionUncontrollable hypertension Deteriorating renal, hepatic or haematologic Deteriorating renal, hepatic or haematologic

statestate Eclampsia or imminently eclampticEclampsia or imminently eclamptic Fetus is compromisedFetus is compromised

Give steroids to mature the fetal lungsGive steroids to mature the fetal lungs APH - abruptionAPH - abruption

How to DeliverHow to Deliver

Deliver vaginally if >37w and Cx is favourable Deliver vaginally if >37w and Cx is favourable or can be ripenedor can be ripened

Caesarean only if the above not metCaesarean only if the above not met Elective CS usually at gestations <35wElective CS usually at gestations <35w Inappropriate attempts at delivery when it is Inappropriate attempts at delivery when it is

not indicated is an invitation to CS (and more not indicated is an invitation to CS (and more CS) CS)

Deliver in an environment that can cope with Deliver in an environment that can cope with a severe multisystem diseasea severe multisystem disease

Don’t overlook patient’s and family’s psychological needsDon’t overlook patient’s and family’s psychological needs

Intrapartum CareIntrapartum Care

Assess convulsive risk and consider Assess convulsive risk and consider prophylactic MgSOprophylactic MgSO4

Control BP with an epidural or IV HydralazineControl BP with an epidural or IV Hydralazine Careful fluid balanceCareful fluid balance Monitor the fetusMonitor the fetus Avoid ergometrineAvoid ergometrine

Postpartum CarePostpartum Care Things may get worse before they get Things may get worse before they get

betterbetter Oliguria for 24 hours is commonOliguria for 24 hours is common

Seizure risk is greatest for 48 hrsSeizure risk is greatest for 48 hrs Continue MgSOContinue MgSO4 infusion for 24 hrs infusion for 24 hrs

Avoid NSAIDsAvoid NSAIDs Treat any BP >150/100Treat any BP >150/100 OK to discharge 3 days after BP OK to discharge 3 days after BP

controlcontrol Follow up weekly to 6w then 3mFollow up weekly to 6w then 3m

The Prognosis after Pre eclampsiaThe Prognosis after Pre eclampsia

Mild pre eclampsia near term has a low Mild pre eclampsia near term has a low recurrence riskrecurrence risk

Unless there is a new partner or a long gap to the next Unless there is a new partner or a long gap to the next pregnancypregnancy

Severe pre eclampsia prior to 34w has a 50- Severe pre eclampsia prior to 34w has a 50- 66% recurrence risk66% recurrence risk

Most recover by 12w but these patients are at Most recover by 12w but these patients are at increased lifetime risk of hypertension and increased lifetime risk of hypertension and related diseaserelated disease

Risk factors for severe pre eclampsiaRisk factors for severe pre eclampsia

Previous pre eclampsia at <35wPrevious pre eclampsia at <35w Renal diseaseRenal disease ThombophiliasThombophilias Autoimmune disease e.g. SLEAutoimmune disease e.g. SLE DiabetesDiabetes Multiple pregnancyMultiple pregnancy Severe alloimmunisationSevere alloimmunisation Family history of pre eclampsiaFamily history of pre eclampsia ObesityObesity Increasing maternal ageIncreasing maternal age

The prevention of pre eclampsiaThe prevention of pre eclampsiawith low dose Aspirinwith low dose Aspirin

History of fetal death or severe IUGRHistory of fetal death or severe IUGRPatients who required delivery for pre Patients who required delivery for pre

eclampsia prior to 34weclampsia prior to 34w You need to treat 4-5 to prevent one FDIU or You need to treat 4-5 to prevent one FDIU or

severe IUGRsevere IUGRDoes Does notnot increase the risk of APH or PPH increase the risk of APH or PPH

Conditions with high risk of pre eclampsia Conditions with high risk of pre eclampsia eg Lupus or homozygous for thrombophiliaeg Lupus or homozygous for thrombophilia

These patients also require heparinThese patients also require heparin

Also give Ca supplements 1.5 G/dayAlso give Ca supplements 1.5 G/day

For the NICE Guideline go For the NICE Guideline go toto

http://pathways.nice.org.uk/pathways/http://pathways.nice.org.uk/pathways/hypertension-in-pregnancyhypertension-in-pregnancy

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