Diagnosis of Hypertrophic Cardiomyopathy in Pregnancy
The diagnosis of HCM in pregnant women relies primarily on echocardiography performed each trimester or when symptoms develop, supplemented by clinical assessment of symptoms (dyspnea, chest pain, palpitations), evaluation of left ventricular outflow tract obstruction, arrhythmias, and ventricular function. 1
Pre-Pregnancy and Initial Assessment
Echocardiography is the cornerstone diagnostic tool to evaluate:
- Ventricular function and wall thickness 1
- Mitral regurgitation severity 1
- Left ventricular outflow tract obstruction (LVOTO) gradient 1
Exercise testing (preferably pre-pregnancy or to 80% of predicted maximal heart rate in asymptomatic pregnant women) should be performed to assess:
Monitoring During Pregnancy
Serial Echocardiography Protocol
Perform echocardiography at specific intervals based on risk stratification:
WHO Class II patients (most women with HCM: mild-to-moderate LVOTO, asymptomatic or well-controlled on medication): Assessment each trimester 1
WHO Class III patients (severe LVOTO, symptomatic despite optimal medication, moderate LV dysfunction): Monthly or bimonthly evaluation in specialized centers 1
It is reasonable to perform serial echocardiography particularly during the second or third trimester when hemodynamic load is highest, or if clinical symptoms develop. 1
Clinical Monitoring Focus
At each assessment, evaluate:
- Symptomatic status (dyspnea, chest pain, palpitations) 1
- LV outflow tract obstruction progression 1
- Arrhythmias (particularly atrial fibrillation) 1
- Ventricular systolic function 1
Fetal Assessment
Fetal echocardiography may be considered for diagnosis of fetal HCM in the context of prenatal counseling, particularly in families with history of pediatric disease onset or severe disease manifestations. 1
Key Diagnostic Considerations
Timing of Complications
Most complications occur in the third trimester when hemodynamic load peaks, making this the critical period for intensified monitoring. 1
Symptoms Requiring Investigation
Approximately 25% of pregnant women with HCM develop symptoms or complications, with most having pre-existing symptoms before pregnancy. 1
New or worsening symptoms warrant immediate echocardiographic evaluation:
LVOTO Assessment
LVOT gradients tend to increase slightly during pregnancy due to increased blood volume and cardiac output, though outcomes are similar between women with and without obstruction. 1
Multidisciplinary Coordination
Care should be coordinated between a cardiologist and obstetrician, with consultation from maternal-fetal medicine specialists for high-risk patients. 1
Common Pitfalls to Avoid
- Do not delay echocardiography if new symptoms develop, even if routine trimester assessment was recently completed 1
- Do not assume stability based on pre-pregnancy status; physiological changes of pregnancy can unmask or worsen disease 1
- Do not overlook arrhythmia monitoring, as pregnancy represents a hypercoagulable state that increases thromboembolic risk with atrial fibrillation 2