How do I manage the pregnant woman with dilated cardiomyopathy?

The management of a pregnant woman with dilated cardiomyopathy should be considered in terms of maternal risk, and risk to the fetus.

Maternal risk
This relates to the degree of ventricular dysfunction and the ability to adapt to altered haemodynamics. Risk and management
can therefore be discussed in relation to New York Heart Association (NYHA) functional class:

NYHA I-II
• Should manage pregnancy without difficulty (maternal mortality 0.4%)
• May require admission for rest and diuretic therapy
• Venous thrombosis prophylaxis with heparin for patients on bedrest

NYHA III
• At significant risk (maternal mortality for NYHA III-IV 6.8%)
• Planned hospital admission for rest, treatment of heart failure and monitoring
• Risk of deterioration in ventricular function which may not improve post-partum.
• Early delivery if heart failure progressive despite optimal inpatient management

NYHA IV
• Should be advised not to become pregnant. Therapeutic abortion should be considered.

Fetal risk
Fetal risk should be considered in terms of two factors:

1. Factors which put the mother at risk
2. Adverse effects from maternal drugs:
   
   • ACE inhibitors should be discontinued prior to conception because of the risk of embryopathy
   • Limited or unfavourable data on fetal effects of many antiarryhthmics
   • Beta blockers may be associated with maternal hypotension, and hence reduce placental perfusion. They may thus contribute to premature labour
   • Warfarin

Note that digoxin and verapamil are safe to use.