Recognise cardiac symptoms that exceed normal pregnancy physiology, assess lesion-specific maternal risk and coordinate a pregnancy heart team plan through the vulnerable postpartum period.
Pregnancy increases cardiac output and circulating volume while lowering systemic vascular resistance. A healthy circulation accommodates these changes, but a stenotic valve, failing ventricle, pulmonary vascular disease or vulnerable aorta may not. The challenge is to distinguish expected symptoms from objective deterioration. Mild breathlessness without abnormal examination can be physiological, whereas orthopnoea, exertional syncope, hypoxia, persistent resting tachycardia or a new diastolic murmur should lead to investigation.
Preconception assessment should define anatomy and physiology rather than only record a historical label such as repaired congenital heart disease. Review ventricular function, residual shunts or valve lesions, pulmonary pressures, rhythm history, oxygen saturation, aortic dimensions, exercise tolerance and previous cardiac events. Discuss medicines, anticoagulation, inheritance, contraception and reproductive preferences. Some patients need intervention or optimisation before conception, and those already pregnant need prompt assessment without assumptions about what decisions they will choose.
Congenital lesions, valve disease, cardiomyopathy and aortopathy can predate pregnancy, with risk determined by residual anatomy and physiological burden rather than diagnosis alone.
Peripartum cardiomyopathy, spontaneous coronary artery dissection, thrombosis and hypertensive cardiac injury may first present during pregnancy or the postpartum period.
Greater plasma volume, stroke volume and heart rate increase cardiac output, challenging a ventricle or valve that has limited reserve.
Fixed obstruction, pulmonary vascular disease and preload-dependent circulations respond differently to vasodilatation, fluid shifts and tachycardia, requiring individualised management rather than one cardiac protocol.
Uterine contraction and mobilisation of retained extracellular fluid increase venous return after birth, potentially precipitating congestion or failure in a vulnerable circulation.
Orthopnoea, elevated jugular venous pressure, crackles or resting desaturation indicate possible failure rather than isolated dependent ankle swelling.
Exertional syncope or chest pain with a significant systolic murmur may reflect severe outflow obstruction and needs urgent echocardiographic assessment.
Palpitations accompanied by hypotension, chest pain, fainting or pulmonary oedema require immediate rhythm diagnosis and treatment.
Abrupt severe chest or back pain in connective-tissue disease or known aortic dilatation should activate an emergency dissection pathway.
Normal pregnancy can cause mild exertional symptoms, but orthopnoea, hypoxia, syncope, pathological murmurs or objective congestion require assessment for disease.
Sudden breathlessness, pleuritic pain, tachycardia or hypoxia can mimic cardiac failure and requires an appropriate pregnancy-specific diagnostic and treatment pathway.
Both can cause tachycardia and reduced exercise tolerance, may worsen established heart disease and should be considered without prematurely excluding structural pathology.
Circulatory demand can unmask ventricular dysfunction or provoke sustained rhythm disturbance, compromising maternal perfusion and fetal oxygen delivery.
Mechanical valves, cyanotic disease and specific aortopathies carry risks that may require specialist anticoagulation, surveillance or intervention throughout pregnancy and postpartum.
Maternal hypoxia, reduced cardiac output or necessary treatment can contribute to impaired fetal growth, prematurity and inherited cardiac disease requiring targeted assessment.
Residual valve disease, arrhythmia substrate or ventricular dysfunction can remain important long after congenital cardiac repair.
Delaying necessary imaging or cardioversion can worsen maternal perfusion and oxygenation, creating greater fetal risk than timely treatment.
The early days after delivery may challenge the heart more than a stable antenatal visit, so observation plans must extend beyond birth.
A routine third-stage prescription can cause avoidable harm when pulmonary pressure, coronary perfusion or a fixed cardiac output makes haemodynamic shifts poorly tolerated.
Attributing orthopnoea or persistent resting tachycardia to normal pregnancy without objective assessment.
Using a historic mWHO category without reviewing ventricular function, aortic dimensions or current guideline changes.
Automatically choosing caesarean birth for every cardiac diagnosis.
Substituting prophylactic-dose LMWH for a mechanical-valve anticoagulation plan.
Withholding defibrillation or synchronised cardioversion because the patient is pregnant.
Ending follow-up at delivery despite significant cardiac disease or new peripartum cardiomyopathy.
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Eight days after an uncomplicated vaginal birth, a previously healthy woman develops orthopnoea, resting tachycardia, basal crackles and oxygen saturation of 91%. What is the most appropriate initial response?
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 7 Sept 2026; clinical approval remains outstanding.
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Symptoms may reveal previously unknown acquired disease. Peripartum cardiomyopathy presents with heart failure towards the end of pregnancy or in the months after birth, without another explanation for left ventricular systolic dysfunction, commonly with ejection fraction below 45%. Do not dismiss postpartum breathlessness as anxiety, sleep deprivation or deconditioning before examining and measuring oxygenation. Myocardial infarction, including pregnancy-associated spontaneous coronary artery dissection, pulmonary embolism and aortic dissection also require a low threshold for urgent assessment.
Investigations should answer the suspected diagnosis promptly. ECG, echocardiography and appropriate blood tests are readily available and do not expose the fetus to ionising radiation. Chest radiography, CT or coronary imaging may still be necessary; the danger of a missed maternal emergency usually outweighs the small diagnostic exposure risk. Explain the purpose and expected consequences, involve radiology for protocol optimisation and avoid letting repeated discussion delay an urgent decision.
Medicines require an indication-specific review. ACE inhibitors, ARBs, ARNIs and some other standard heart-failure medicines are unsuitable during pregnancy, but stopping every cardiac drug can destabilise the patient. Diuretics can be used for genuine congestion with careful volume assessment, and selected beta-blockers may be needed for arrhythmia or cardiomyopathy with fetal-growth monitoring. A mechanical valve creates a particularly high-stakes anticoagulation problem: transitions between vitamin K antagonists and therapeutic heparin must be designed and monitored by specialists.
Labour planning should consider the haemodynamic lesion, pain, preload, afterload and potential blood loss. Vaginal birth is appropriate for many patients and caesarean birth is reserved for obstetric or specific cardiac indications. Regional analgesia can reduce stress but sudden vasodilatation may be poorly tolerated in fixed-output or preload-dependent disease. Plan third-stage medicines before labour: ergometrine and carboprost are inappropriate in some cardiac conditions, and oxytocin may need a slow infusion to avoid abrupt haemodynamic change.
Risk persists after delivery because autotransfusion from the uterus and shifts in extracellular fluid increase circulatory load. Record the observation location, duration, fluid balance, anticoagulation restart and heart-failure medication plan. Discuss breastfeeding and contraception with the patient, using evidence for the actual medicines required. Review future pregnancy risk after recovery rather than assuming that an uncomplicated birth proves subsequent pregnancy will be low risk.
Avoid indiscriminate diuresis in preload-dependent lesions or hypovolaemia; monitor blood pressure, urine output, electrolytes and renal function and assess fetal wellbeing.
Exclude pre-excitation and relevant contraindications, including severe asthma; urgent cardioversion takes priority in instability. This guideline sequence differs from some product SmPC schedules and requires protocol-based prescribing.