Fortunately, there are not many women of child-bearing age who experience a myocardial infarction (MI, or “heart attack”). Since this is generally uncommon, there are no large data from which recommendations can be made for pregnant women with a prior MI.
The believed risks of pregnancy for women with a prior MI relate to the physiological changes of pregnancy, including increased blood volume, heart rate, cardiac output, and an increased risk of thrombosis. These changes may affect cardiac function during pregnancy, which could be a risk to the patient or the pregnancy.
Small case series for women with prior MI seem to indicate that pregnancy usually is uncomplicated. For women with cardiac disease in general, the highest risk patients appear to be ones with left heart obstruction, ventricular dysfunction, arrhythmia, and prior cardiac events, such as heart failure, TIA, or a stroke. However, it is shown that only a small amount of patients that had a prior cardiac event developed heart failure.
In general, the best predictor of pregnancy outcome in women with heart disease is their NYHA class. Patients with class I disease (no symptoms with exertion) have a very low incidence of cardiac events or death during pregnancy. However, due to the limited data, it is not possible to provide a precise risk assessment for future pregnancy. However, there are some general assumptions:
- The most conservative approach is not to become pregnant.
- For women with a prior MI, normal ventricular function, and NYHA class I disease, the risk of a cardiac event ranges from 2% to approximately 20%. Case series suggests that the risk is actually towards the lower of the percentage range.
- Patients should be monitored closely during pregnancy by an OB and cardiologist for the development of cardiac complications.
- Lipid-lowering agents and ACE-inhibitors should be avoided during pregnancy.
- Platelet receptor blockers are typically discontinued during pregnancy, although it is not clear that they pose any risk to the fetus.
- Beta blockers, low-dose aspirin, and heparin can be used safely during pregnancy as indicated.
Maternal Fetal Medicine blogs are intended for educational purposes only and do not replace certified professional care. Medical conditions vary and change frequently. Please ask your doctor any questions you may have regarding your condition to receive a proper diagnosis or risk analysis. Thank you!