Heart Disease Complicating Pregnancy

Overview

Heart disease complicating pregnancy refers to pre-existing or newly acquired cardiovascular conditions that affect maternal and fetal health during gestation, labor, and the postpartum period. Globally, it affects 1-4% of pregnancies, with higher burdens in low- and middle-income countries (LMICs) like Sri Lanka, where it is a leading indirect cause of maternal mortality, accounting for 17.3-17.25% of maternal deaths, second only to postpartum hemorrhage. The cause-specific maternal mortality ratio (MMR) for heart disease in Sri Lanka was 7.24 per 100,000 live births from 2006-2018. Rheumatic heart disease (RHD) remains the predominant type (21.1-70.25% of cases), followed by cardiomyopathies (20.7%) and congenital heart disease (CHD, 12-18.1%). In Sri Lanka, pooled prevalence of heart disease in pregnancy is around 1.46% in South Asia, with local studies showing 0.95% in tertiary care settings. Management requires multidisciplinary care involving obstetricians, cardiologists, and anesthetists, with guidelines from the Sri Lanka College of Obstetricians & Gynaecologists (SLCOG) emphasizing early detection and risk stratification. Key resources include the SLCOG's "Heart Disease Complicating Pregnancy – Management Strategies" (2014) available here and "Immediate Resuscitation Following Maternal Collapse During Pregnancy" (2021) PDF here, as well as the National Guidelines for Maternal Care (Ministry of Health, 2015) Volume III here. International references like the 2025 ESC Guidelines for Cardiovascular Diseases in Pregnancy are adapted locally.

Classification

Heart diseases in pregnancy are classified using the modified World Health Organization (mWHO) risk classification, adopted in Sri Lanka:

• Class I: Low risk (e.g., mild pulmonary stenosis, repaired atrial septal defect).

• Class II: Moderate risk (e.g., unrepaired atrial septal defect, mild left ventricular impairment).

• Class II-III: Intermediate risk (e.g., moderate mitral stenosis, mechanical valves).

• Class III: High risk (e.g., severe mitral stenosis, NYHA class III/IV symptoms).

• Class IV: Extremely high risk, pregnancy contraindicated (e.g., pulmonary arterial hypertension, severe left ventricular dysfunction EF <30%).

In Sri Lanka, RHD (e.g., mitral stenosis) often falls in Class II-III, while peripartum cardiomyopathy is Class III-IV.

Signs and Symptoms

Symptoms may mimic normal pregnancy changes but warrant investigation: dyspnea, orthopnea, palpitations, chest pain, syncope, fatigue, or hemoptysis. Signs include cyanosis, clubbing, elevated jugular venous pressure, murmurs, or edema. In advanced cases, heart failure or arrhythmias present. In Sri Lanka, antenatal cardiac examination at the first visit is mandatory to detect asymptomatic cases.

Causes and Pathophysiology

Primary causes in Sri Lanka are RHD (valvular lesions from streptococcal infections), cardiomyopathies (peripartum or dilated), and CHD (e.g., atrial septal defects). Pregnancy increases cardiac output by 30-50%, exacerbating underlying conditions through volume overload, tachycardia, and hypercoagulability, leading to heart failure, arrhythmias, or thromboembolism. In LMICs, delayed diagnosis and infections contribute.

Risk Factors

Pre-existing heart disease, advanced maternal age (>35), obesity, hypertension, diabetes, smoking, and multiparity. In Sri Lanka, history of rheumatic fever, poor socioeconomic status, and limited access to cardiology services increase risks. Medically contraindicated pregnancies account for 19% of related deaths.

Diagnosis

• Antenatal screening: History, clinical exam, ECG, echocardiography (essential for valvular assessment). BNP levels for heart failure suspicion.

• Risk assessment: mWHO class at booking visit; high-risk referred to tertiary care.

• In Sri Lanka, SLCOG recommends multidisciplinary clinics for Class II-IV cases, with fetal echocardiography if CHD suspected.

Treatment

Management is risk-based and multidisciplinary:

• Antenatal: Frequent monitoring (every 4-6 weeks for low risk, 2-4 weeks for high). Beta-blockers (e.g., metoprolol) for arrhythmias, anticoagulants (LMWH for mechanical valves), and diuretics for fluid overload. Avoid ACE inhibitors/ARBs.

• Specific Conditions: For RHD, penicillin prophylaxis; balloon valvuloplasty for severe mitral stenosis. Cardiomyopathies require heart failure therapy; pulmonary hypertension (Class IV) advises termination if early.

• Intrapartum: Vaginal delivery preferred unless contraindicated; epidural anesthesia, assisted second stage. Continuous monitoring, avoid ergometrine.

• Postpartum: Close observation for 72 hours; contraception counseling (avoid estrogen-based).

• In emergencies: SLCOG guidelines for maternal collapse include left lateral tilt, CPR modifications, and perimortem cesarean. In Sri Lanka, 65.5% of deaths involve delays; 55.6% are preventable with better care.

Prevention

Preconception counseling for women with known heart disease: Optimize condition, adjust medications, folic acid. Antenatal: RHD prevention via streptococcal treatment, vaccination. Sri Lanka's Maternal Death Surveillance and Response (MDSR) identifies gaps; SLCOG promotes "Cardiac Day" education.

Prognosis

With optimal care, maternal mortality is low in Class I-II (0.5-1%), but rises to 30-50% in Class IV. In Sri Lanka, maternal mortality rate among affected women is 0-3.2% in studies, with fetal loss 5-10%. Long-term: Increased risk of future CVD; postpartum follow-up essential.

Epidemiology

In Sri Lanka, heart disease causes 17-21% of maternal deaths, with RHD dominant due to endemic rheumatic fever. Prevalence in pregnancy: 0.95-1.5% in hospital data, higher in rural areas. Trends show slight increase with rising NCDs, but MDSR has reduced overall MMR to <30/100,000 by 2025.

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