Hypertension in Pregnancy

& Medication

Mark Finney, Consultant Obstetrician

Andrea Goodlife & Claire Dodd, Specialist Hypertension Midwives

Essential Hypertension

• Pre-existing raised BP

• May be on treatment or just under

observation

• May be known prior to pregnancy or detected

at booking as raised BP

Cardiovascular changes of Pregnancy

• Massive changes in

cardiac output and

haemodynamics

• Already occurred

largely by 12 weeks

Risks to Mum Risks to Baby

• Worsening of BP

• Superimposed pre-

eclampsia (PET)

• Medical over-

intervention

• Teratogenesis from

certain drugs (eg ACE-I)

• IUGR

• PET

• Hypoglycaemia if on

labetolol &

breastfeeding

Pre-pregnancy

• If planned, review medications

– Take off teratogenic meds eg ACE-I or similar

– Take off diuretics

• Optimise diet

• Stop smoking

• Start folic acid

Early pregnancy

• Review meds at booking

• Take off any teratogenic meds

• Early booking at hospital for risk review

• Dating scan +/- NT (combined) scan

• Plan for pregnancy

– Including issues re: obesity, screening for GDM

Pregnancy

• Regular BP checks

• May need to come off meds if BP ↓↓

• May need to start or restart meds later in

pregnancy as BP rises

• Serial growth scans

• Joint care between MW & hospital

Later Pregnancy

• If BP well controlled & fetal growth normal,

aim to labour spontaneously or IOL for

postdates

• If BP raised, try control first with medications

• If superimposed PET or fetal growth issues,

consider delivery

Post delivery

• Watch BP for at least 24-48 hours

• May need oral antihypertensives

• Communicate closely with GP to ensure that

BP monitoring is taken over & ongoing care is

handed over to GP

Pre-Eclampsia

Definition

• Hypertension + proteinuria with onset ≥20 weeks

• Diastolic ≥90mmHg on 2 occasions 4-6 hours apart OR ≥110mmHg on one occasion

• Proteinuria >300mg/24 hours

• Symptoms of PET

• Differentiation from PIH/renal disease

Hypertensive disorders

No proteinuria -

PIH

Mild and moderate PET Severe PET Eclampsia HELLP

Proteinuria and Raised BP

Pre -eclampsia

Pregnancy induced hypertension(Raised BP after 20 weeks)

Chronic hypertension(Raised BP before 20 weeks gestation)

Raised BP in pregnancy> or = 140/90

Incidence of PET

• 2-3% pregnancies

• 5-7% primips

• 1.8% PET will develop eclampsia

• Worldwide 1.5-8 million develop PET;

• 150 000 deaths

Importance

• Maternal morbidity

– Neurological

– renal

• Fetal death

– Abruption, hypoxia, IUGR

• Fetal morbidity

– Prematurity (PET is cause of >40% iatrogenic PTB) with

risks respiratory and neurodevelopmental complications

(inc. learning difficulty/↓IQ in up to 60%)

Risk Factors for PET

• Primip

• Pregnancy interval > 10

yrs

• Family history (1 in 3

risk if mother had PET)

• Twins/multiples

• Previous history PET

• Essential hypertension

• Renal disease

• SLE

• APLS

• Thrombophilias

• Age >40

• Obesity

LDA

• 75mg Aspirin recommended from 12 weeks

for those with risk factors

• Reduction 10-15% in PET

PET Pathophysiology

• Pregnancy specific syndrome

• Placenta has a central role to play

– Reduced placental perfusion

– Inadequate vascular remodelling at ~16 wks

• Genetic component in some women

– No candidate genes or consistent results

2 stage process

• Inadequate implantation

• Poor remodelling• Cytokines produced +

growth factors

• ↑placental apoptosis/necrosis

• Shedding of microparticles into circulation

• Markers seen

preceding PET

• Inflammation &

endotheial activation

STAGE 1: Reduced

placental perfusion

STAGE 2: Maternal

syndrome

(multisystem disorder)

PET Diagnosis

• Hypertension >140/90

• Proteinuria >300mg in 24 hours

Mild PET

• Classically asymptomatic

• BP 140/90 (ish)

• Maybe trace / + proteinuria

• Often incidental finding at CMW clinic

attendance

What questions should you ask?

• Headache

• Oedema – especially hand / face

• Visual disturbances (‘flashing lights’)

– Sign of cerebral vasospasm/impending eclampsia

• Epigastric pain

– Hepatic congestion/liver capsule stretching

• Is baby moving normally?

– Fetal wellbeing

PET Investigations

• FBC platelet count

• U+E signs renal dysfunction

• LFTs elevated transaminases

• Clotting (not routinely if plts > 100)

• PCR >30 = abnormal

• MSU (to exclude UTI as cause of protein)

Abnormal results in pregnancy

• Creatinine > 70

• ALT > 32

PET fetal surveillance

• Fetal assessment

– Clinical

– USS for growth

– CTGs

Monitoring

• Monitor BP

– CMW

– Day assessment or Triage

• Monitor bloods

– Weekly or twice weekly

• Monitor fetus

– CTG

– Serial USS

Definitive treatment

• Deliver when:

– BP/protein or clinical condition deteriorates so

becomes moderate or severe PET

– Fetal condition mandates delivery even if

maternal condition stable

Severe PET

• SYSTOLIC 160-180

• DIASTOLIC >110

• CNS

– Headache

– Visual disturbances

– Disorientation/

irritability

– Hyperreflexia

– Clonus >3beats

• Hepatic

– Abnormal LFTs, dysfunction

– RUQ pain

– Epigastric pain

• Renal

– Elevated creatinine, urea

– Oliguria

– Heavy proteinuria

• Haemtological

– Thrombocytopaenia

– Haemolysis

Multisystem disease

• Eyes– Arteriolar spasm

– Retinal haemorrhages

– Blindness

– Scotoma

– Papilloedema

• CNS– Seizures

– Encephalopathy

– Cerebral haemorrhages

– CVA

• Respiratory– Pulmonary oedema

– ARDS

• Liver– Subcapsular haemorrhages

– Liver rupture

• Kidneys– Acute renal failure

• Fetoplacental Unit– IUGR

– Abruption

– Fetal compromise

– Fetal death

• Haemotological– DIC

– haemolysis

Symptoms

• Headache (↑BP)

• Flashing lights (lightning) (cerebral oedema)

• Epigastric pain (stretching of liver capsule)

• Oedema (↓albumin/↑BP)

• Asymptomatic

Management of Severe PET

• Immediate admission to hospital - 999

• High dependency care

• Invasive monitoring

– NICU for baby if early gestation

• Senior multidisciplinary involvement early

– Obstetrics & Anaesthetics

Aims of treatment

• Aims

– Prevent seizures

– Control hypertension (to prevent cerebral

haemorrhage)

– Deliver safely (stabilise, +/- IUT, +/- steroids)

Maternal Assessment

• BP-check every 15 minutes

• Urine output-hourly

• Urinary protein dipstix

• Strict fluid balance chart

• Bloods

– U+E, urea, creatinine,

– FBC esp. platelets (G+S)

– LFTs

• Deep tendon reflexes and presence of clonus

• CTG

Control BP

• Antihypertensives – aim diastolic 85-95

– IV / oral labetolol (Avoid if asthmatic or signs of pulmonary oedema)

– IV hydralazine (5mg every 15 minutes for acute control BP)

– Oral Nifedipine 10mg SR

– Methyldopa TOO SLOW ONSET (24-48 hours) for use in acute situation

– Titrate IV antihypertensive vs. BP then infusion

Prevent Fits

• Magnesium sulphate

– All severe and moderate PET

– 4g IV over 15 minutes

– Then infusion 1g/ hour

– Monitor reflexes (present) urine OP (>30ml/hr) and respiratory rate (>12/minute)

– Slows neuromuscular conduction and decreases CNS irritability

– Best anticonvulsant in these circumstances AND IN ECLAMPSIA

Magnesium toxicity

• If urine OP OK then likely

not to accumulate (85%

renal excretion)

• If urine output falls,

reduce dose to 0.5g/hour

• If signs toxicity, stop

• Antidote = Calcium

gluconate 1g IV over 3

minutes

• Magnesium levels

– Therapeutic 2-4 mmol/l

– Warmth, flushing, slurred speech

3.8-5mmol/l

– Loss of patellar reflexes >5 mmol/l

– Respiratory depression >6 mmol/l

– Respiratory arrest 6.3-7mmol/l

– Cardiac arrest, asystole >12

mmol/l

Deliver Baby

• If severe PET, do NOT transfer

• Ensure SCBU aware if baby premature

• Give antenatal steroids if time but usually, if require IV therapy, delivery is indicated once stabilised

• If cervix favourable and patient >34 weeks, consider short trial IOL

• If cervix unfavourable and/or <34 weeks, deliver by LSCS

• Anaesthesia epidural vs. general

DELIVERY

• Risk of sharp rise of BP on intubation

• Need experienced and senior anaesthetist

to give GA in these circumstances

• The mother is the priority

Eclampsia

• Occurrence of fits

– 44% postpartum

– 38% antenatal)

– ALWAYS GRAND MAL

• Due usually to cerebral vasospasm

• Do not try to shorten initial convulsion (self-limiting)

• Prevent maternal injury

• Maintain oxygenation

• Prevent aspiration

• ABC…

Eclampsia

• Beware known epileptics

– If BP normal, no protein, typical for their type

of fit-may be epilepsy BUT any fit must be

considered as eclampsia until proven

otherwise especially of BP slightly up etc

• Any FOCAL fit is not eclampsia

– Consider: cerebral bleed/infarction due to

severe PET

– Arrange head CT urgently

Collaborative Eclampsia Trial

• Comparisons:

– MgSO4 vs. diazepam

• 52% lower risk recurrent convulsions with MgSO4

– MgSO4 vs. phenytoin

• 67% lower risk recurrent convulsions with MgSO4

• Maternal mortality non-significantly lower in MgSO4

• Less risk of pneumonia, ventilation, ITU with Magnesium

• Babies less likely to be intubated and go to SCBU

Eclampsia

• Treatment is IV magnesium sulphate-4g loading then

1g/hr

• If recurrent fits or fit already on MgSO4, then further

2g IV bolus/increase infusion to 1.5g/hr

• If fits persist, check magnesium levels, contact

anaesthetists, consider CT, consider intubation and

ventilation

• If antenatal, stabilise & DELIVER

Postnatal care

• Watch closely on HDU/LW until diuresis and condition improving

• Anticipate possible worsening or seizures in first 18-24 hours

• Continue MgSO4 for 24 hours and then review

• Do not need to taper off MgSO4

Postnatal Management-Hypertension

• Hypertension may persist for some weeks

• Switch to oral treatment when feasible

– Labetalol

– Enalapril

– Nifedipine

• Polypharmacy may be required to control BP

• Not methyldopa

• Ensure regular BP checks arranged on discharge with review and follow-up by GP

Postnatal Management-Fluids

• Fluid overload real danger after delivery

– Relaxed vigilance

– LSCS

– PPH

– Physiological oliguria

• STRICT FLUID BALANCE

Postnatal Management-Fluids

• Women with PET are very vulnerable to Pulmonary oedema

• Carries risk of ARDS if severe or not recognised rapidly

• ARDS may be fatal

• Fluid restriction is far SAFER

– Renal function more likely to recover than pulmonary and less likely to kill patient

Fluid Balance

• Take Home messages:

– Fluid restrict as pt already fluid overloaded

– Scrupulous input and output

– Do not fluid challenge

– Do not give frusemide

– Consider CVP line if urine output poor

– Seek senior advice early

– Multidisciplinary Mx-obs/anaesth/renal teams

Disease Progression

• Often improve quickly

• Some may deteriorate further immediately after

delivery – may continue to worsen for 24 + hours

– Worsening BP

– Worsening bloods

– Oliguria/anuria

– Increased risk fits

• Consult seniors & manage with MDT

HELLP syndrome

• Haemolysis

• Elevated

• Liver Enzymes

• Low

• Platelets

• 1-12% PET (usually severe end of spectrum)

• Commoner in multips

• Variable presentation– RUQ pain, epigastric pain,

nausea + vomiting

– 85% hypertensive at presentation

• Present: 2/3 antepartum, 1/3 postpartum– mid 2nd trimester to several

days postnatal

Differential diagnosis in HELLP

• Any liver problems

– Biliary colic

– Cholecystitis

– Hepatitis

• Gatroenteritis or reflux

• Pancreatitis

• ITP/ TTP

• Ureteric colic

• Renal calculus

• Acute Fatty liver of

pregnancy

• Rare-if severe pain:

• Aortic dissection

• MI

HTN Treatment Summary

Nifedipine (Adalat)

� In the obstetric department we always give Modified Release

� 2 types of MR are SR or LA

�Grapefruit juice increases blood levels of meds

so avoid!

� Pure Nifedipine is NOT given, this drops the BP too quickly, and

will interrupt uterine placental flow.

Nifedipine Slow Release (SR)

• Calcium channel blocker

• Cardiogenic shock/within 1 month of MI

• Side effects:

• May inhibit labour/ headaches/ flushing/ dizziness/ palpitations/fluid retention

• BD or Stat Response

• Given AN or PN

• Max dosage 80mgs

• Given as BD or stat dosage (Stat normally 10 or 20mgs)

ADALAT Long Acting (LA)

• Given ONCE a day, (good for compliance)

• PN patients only

• Think “Leave until After”

• Usual dosage 30 60 or 90mgs LA

• Max 90mgs LA

• Husk capsule that the medication is excreted out of the bowel, therefore. Not to be given if Ulcerative colitis / crohns, warn patient they may see the husk!

• If had am dose, BP raised in evening, give SR dose, then increase next days dose of LA

Labetalol

Beta blocker

Not for patients with;

Asthma- bronchospasm plus less responsive to inhalers

Type 1 diabetic part of the warning system for hypo’s is palpitations, labetalol will stop this happening

Phaeochromocytoma

Side Effects:

Scalp tingling/ headaches/weakness/liver damage/GI disturbances

Max dosage:

Up to 800mg in 2 divided doses, or up to 2.4g daily (3-4 divided doses) Usual

starting dose 100mgs BD

Methyldopa

• Centrally acting anti-hypertensive

Not for:

• Severe depressives, methlydopa makes them “dopey and depressive” Not used PN because of risk of PN depression (NICE guidelines stop within 2 days of delivery)

Side effects:

• Depression and tiredness/dry mouth/GI disturbances

Max dosage

3g daily (250mgs TDS as starting dose)

Enalapril

• ACE inhibitor

• Used post natal (not first line)

Side effects

• Dry cough/dyspnoea/depression

Max Dose

40mgs daily (5mgs daily starting dose, check U&E’s)

Hydralazine

• Avoid in:

• severe tachycardia / recent MI/ idiopathic SLE

• Before 3rd trimester (risk/benefit)

• Side effects

• Tachycardia/ flushing/ palpitations

• Dose

• 25mgs BD max 50mgs BD

• IV infusion: 5–10 mg diluted with 10 mL sodium chloride 0.9%; may be repeated

after 20–30 minutes

• Can breast feed

Home Monitoring BP

• Microlife monitors, validated in pregnancy (dinamaps known to under read in PET)

• Cuff size up to 42cm

• Loaned AN and PN

Ideal for:

• WCH/on anti hypertensive/high risk of PET

• Reduces inpatient stay and relieves pressure on community midwives

Providing:

Machine available / compliant / will return the monitor / will appropriately respond to readings / no language barrier (PN) as medication is altered by telephone consultation

Drawbacks of home monitoring

• Not suitable for everyone

• Language barrier can be an issue

• Anxiety provoking

• Risk of non-compliance

• Mental capacity to understand

• Loss of monitor if not returned!

Home Monitoring of BP (AN)

• From 28 weeks (unless clinically indicated)

• Limits set at 140/90

• Offers reassurance

• Allows early detection of elevated blood pressure

• Pt accurately/appropriately medicated with anti hypertensive medication

• If admitted please continue to use the Microlife monitor to attain

readings!

PN Home Monitoring

• For women who have been on antenatal monitoring, or new onset BP requiring medication

• Limits set at 150/100 (Pt call us if exceeds this limit)

• Spec midwife will phone pt every 2 weeks to attain readings and reduce medication according to set algorithm

• Offers accurate diagnosis and allows for appropriate follow up

• Letter to GP to inform on the scheme, and follow up letter upon discharge/transfer of care

• Can be on the scheme for up to three months postnatal

Not Home Monitoring? (NICE)

Chronic and Gest hypertension

• daily for first 2 days after birth

• at least once 3–5 days after birth

• as clinically indicated if antihypertensive treatment changed.

• Offer medical review if still taking antihypertensive treatment 2 weeks after transfer to community care

PET

• 1–2 days for up to 2 weeks after transfer to community care, until antihypertensive treatment stopped and no hypertension

• Offer medical review if still taking antihypertensive treatment 2 weeks after transfer to community care

Finally…

• Shortage of Nifedipine SR (Adalat Retard) 10mg

• 20mg tablets & LA unaffected

• This is the case until Jan 2018 earliest

INSTEAD of Adalat Retard 10mg OD;

� Px ADIPINE MR 10mg BD

Questions??