Heart Murmurs
While you're pregnant, your doctor will often hear a new sound related to the extra blood flowing through your heart. This is called a heart murmur.  Usually this doesn't mean anything is wrong with your heart.  A newly heard murmur can mean that there's a problem with a heart valve.  If a heart murmur occurs, your doctor will be able to determine its cause.

Arrhythmias
Many people have fast or slow heartbeats that may be regular or irregular. These are called "arrhythmias."  They can develop for the first time during pregnancy in a woman with a normal heart or as a result of underlying heart disease not previously known.  Occasionally these arrhythmias are noticed when taking the pulse.  Most often, no symptoms are noticed and no treatment is required.  Sometimes, however, an arrhythmia can cause symptoms such as palpitations, dizziness or lightheadedness.  On rare occasions it can even cause fainting.

There can be other explanations for these symptoms, but if you have them, your doctor may want to check you for arrhythmias.  Besides examining you, your doctor may want to perform an ECG or have you wear a heart monitor for 24 hours to better understand your rhythm.

Again, most often you won't need treatment.  If specific treatment is required, your doctor will advise you about its effect on you and your baby.

High Blood Pressure
High blood pressure, or hypertension, is a serious complication of pregnancy.  It occurs in about 6 to 8 percent of pregnant women.  In a small number of cases, it's present before pregnancy.  It is important that you have your blood pressure checked often throughout your pregnancy.

Very high blood pressure can occur, with a rapid weight gain, swollen ankles and protein in the urine. This disorder is knows as "toxemia of pregnancy" or "pre-eclampsia."

This is a serious complication of pregnancy.  It requires immediate medical attention.