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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??
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