Cardiac disease in pregnancy



·        Cardiovascular changes

·        General principles

·        Mortality risk

·        Specific diseases


Cardiovascular changes in pregnancy:


·      ↑Cardiac output (↑50% by end T2) – HR and SV

·      ↓SVR (↓30% by end T1)

·      ↑Blood volume (↑50% by end T2) – RBCs and plasma

·      ↑Coagulability

·      Supine aortocaval compression

·      ±Hypertensive disorders of pregnancy: ↑SVR


·      ↑↑Cardiac output: pain + anxiety + contractions

·      Valsalva manoeuvre


·      ↑↑↑Cardiac output (80% above term baseline)

·      Autotransfusion vs PPH

·      Relief of aortocaval compression

·      High of decompensation for several hours


·      IV fluid: ↑preload, ↑risk APO

·      Oxytocics: oxytocin ↓SVR, ergot/PGF2α ↑↑SVR, ↑PVR



Model of care

·      Tertiary centre

·      Obstetrician-led

·      Multi-disciplinary: O&G + paeds + cardiology + anaesthesia + ICU

·      Frequent review

·      Clear birth plan

Serial assessments

Changes are progressive – may be ok in T1 but not in T3

·      History: chest pain, dyspnoea, orthopnoea

·      Examination: volume status, foetal well-being

·      Investigations: ECG, serial TTE, MRI

Risk stratification

Highest risk:

·      Pulmonary hypertension

·      Peripartum cardiomyopathy

·      Fixed output lesion = intolerance of high venous return

·      Dilated aorta = risk of pop

·      Severe anything

CARPREG score:

·      Prior cardiac event (AMI, APO, arrhythmia, stroke)

·      Baseline impairment (NYHA 3+, cyanosis)

·      Left heart obstruction (MS, AS, HCM)

·      LV systolic dysfunction (EF)


·      Medication: e.g. beta blocker

·      Surgery: e.g. balloon valvuloplasty, myotomy

·      Balance risks to mother vs foetus

·      Beware teratogens, esp warfarin (T1), ACEi/ARB, amiodarone




·      Default: IOL @ 39+2, early epidural, instrumental, no pushing

·      When: term vs premature, prefer in-hours

·      Where: tertiary centre, labour ward vs ICU

·      What: VD vs CS, spont vs IOL, push vs instrumental, ±epidural

·      Why: risk of lesion (e.g. APO vs pop)

Critical care

·      Pressure monitoring: A-line vs NIBP

·      Venous access: PIVC vs CVC


·      Oxytocics: ergotamine contraindicated for things that go ‘pop’

·      Antibiotics: if abnormal valve, some congenital disease

·      Anticoagulants: continue vs bridge vs cease

·      Vasoactives: β-blocker vs vasopressor vs inotrope


Management of specific diseases:

Ischaemic heart Dx

·      Usual risk factors

·      Best treatment is balloon angioplasty

·      Avoid anti-platelet + thrombolysis

Aortic stenosis

·      Cannot handle ↑↑venous return

·      Ante-partum: balloon dilatation only if severe

·      Intra-partum: ↔SVR, ↔HR, sinus rhythm

Aortic dilatation

·      e.g. Marfan’s syndrome, association with bicuspid valve

·      Risk of aortic dissection

·      Worse with contractions + pushing

·      Worse with PET

·      Ante-partum: TTE every 1-2 months

·      Planning: timing dependent upon a) diameter b) rate of change

·      Intra-partum: aim HR, ↔SVR, ↔SBP, no pushing

·      ? Labour epidural + instrumental delivery + no pushing

Mitral stenosis

·      High mortality

·      Rheumatic disease: Aborigines, overseas-born

·      Risk: ↑↑Venous return -> APO

·      Ante-partum: β-blocker, anticoag, ±balloon dilatation

·      Intra-partum: limit IV fluid

Pulmonary HTN

·      Very high mortality (50%!)

·      Intra-partum: elective GA – cardiac anaes + O&G anaes

Fontan circulation

·      Single ventricle (usually RV – not designed for high workload)

·      Low venous return -> low cardiac output -> low oxygen delivery

·      High systemic venous pressure

·      Risks to mother: arrhythmia, heart failure, VTE, PPH

·      Risks to foetus: miscarriage+++, IUGR, prematurity

Prosthetic valves

·      Aspirin, UFH and LMWH are safe

·      Warfarin is not



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