what cause valves to enlarge in the heart while your pregnant?

Janet,

Thanks for your question.  It is common for women to develop a heart murmur during pregnancy, which is due to a larger circulating blood volume and therefore more flow across the heart valve.  This usually disappears within weeks of the baby's birth.  The valves themselves do not really change, just the flow dynamics.  This does not mean that heart disease, including valvular disease does not occur in pregnancy.  These problems, unfortunately, can cause problems in previously healthy women.  In some cases, there may have been a pre-existing problem that was silent, and with the pregnancy, higher blood volume and flow rate, the patient becomes symptomatic.  Also, another underlying disease may be responsible for your symptoms.  One example is thyroid disease which can occur after pregnancy and cause a murmur and fatigue. 

In your situation, it sounds like you have already delivered the twins, but still have the murmur and much fatigue.  The bottom line here is your symptoms are a concern to you, and you should make an appointment with your primary care physician who will ask further questions and perform an examination.  He will then be able to tell what the problem is, if any.  If necessary, he may request further tests. 

Best wishes. 

Martin Cane, M.D.