Heart Disease in Pregnancy
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Direct answer
Heart disease complicates about one per cent of pregnancies in India, rheumatic mitral stenosis the leading lesion, and remains an important cause of maternal death. Pregnancy raises cardiac output by 30-50 per cent, so stenotic lesions and pulmonary hypertension decompensate while regurgitant lesions and small shunts tolerate the load. Risk is stratified by the WHO classification — class I-II do well with joint care, class III needs specialist centres, and class IV conditions (pulmonary hypertension, Eisenmenger syndrome, severe symptomatic valve disease, poor ventricular function) carry prohibitive risk. Vaginal delivery with early epidural and a shortened second stage suits most; caesarean is reserved for obstetric or specific cardiac indications.
What you must remember
- Lesion risk gradient: mitral stenosis is the worst tolerated common lesion (fixed obstruction against rising flow — pulmonary oedema, atrial fibrillation); severe aortic stenosis behaves similarly; regurgitant lesions, small septal defects and corrected lesions cope.
- WHO risk classes: class I (no increased risk), class II (small increase), class II-III (moderate valve disease, unoperated septal defects), class III (marked — specialist centre), class IV (pulmonary hypertension, Eisenmenger, severe symptomatic stenoses, poor ventricular function or prior peripartum cardiomyopathy with residual dysfunction) — pregnancy is discouraged in class IV.
- Danger windows: rising output peaks late second trimester; labour adds pain-driven surges; and immediate postpartum autotransfusion can flood the pulmonary circuit — the classic moment of collapse in mitral stenosis.
- Red flags of decompensation: progressive dyspnoea at rest or on minimal exertion, orthopnoea, paroxysmal nocturnal dyspnoea, haemoptysis, atrial arrhythmia and rising jugular venous pressure.
- Mitral stenosis care: beta blockade, careful fluid balance, rate control of atrial fibrillation, treatment of anaemia and infection, and balloon mitral valvotomy in selected symptomatic women.
- Delivery planning: vaginal delivery preferred with early epidural, assisted second stage and monitored third stage; caesarean for obstetric indications plus severe stenotic disease, pulmonary hypertension, dilated aortic root or decompensation; endocarditis prophylaxis is not routine, reserved for high-risk cardiac conditions.
- Peripartum cardiomyopathy: systolic dysfunction presenting from the last month of pregnancy to five months postpartum; treat with pregnancy- or lactation-safe heart failure therapy and counsel about recurrence risk if ventricular function has not recovered.
Common confusion
Physiological adaptation and disease are blurred: a soft flow murmur, mild dyspnoea, ankle oedema and sinus tachycardia up to about 100 can be normal, whereas a loud diastolic murmur, dyspnoea at rest, haemoptysis or a rising resting heart rate signal disease. WHO class III needs delivery in a specialist centre; class IV conditions such as Eisenmenger syndrome carry mortality so high that avoiding pregnancy is the counselling answer.
Exam-focused takeaway
Stems ask for the worst-tolerated lesion (mitral stenosis in India), the WHO class IV list, the danger timing (labour and postpartum autotransfusion) and delivery modifications. Balloon valvotomy and peripartum cardiomyopathy counselling complete the set.
Frequently asked questions
Which heart lesion is worst tolerated in pregnancy?
Mitral stenosis — the commonest rheumatic lesion in India — because a fixed obstruction faces a 30-50 per cent output rise, risking pulmonary oedema and atrial fibrillation.
What conditions fall in WHO class IV?
Pulmonary hypertension, Eisenmenger syndrome, severe symptomatic valve disease and significantly impaired ventricular function, including prior peripartum cardiomyopathy.
Why is the immediate postpartum dangerous?
Uterine contraction autotransfuses blood into the circulation, suddenly raising preload and provoking pulmonary oedema in stenotic or failing hearts.
How are most women with heart disease delivered?
Vaginally, with early epidural, an assisted second stage and careful third-stage management; caesarean is for obstetric or specific cardiac indications.
What is peripartum cardiomyopathy?
Left ventricular systolic failure arising in the last month of pregnancy to five months postpartum, treated with pregnancy-safe heart failure therapy; counsel about recurrence risk in future pregnancies.