During pregnancy, changes may occur to the heart and blood vessels. These changes may put extra stress on a woman’s body. Such changes, as listed below, are normal during pregnancy. They help ensure that your baby will get enough oxygen and nutrients.
- Increase in blood volume: During the first trimester, the amount of blood in the body increases by 40 to 50 percent and remains high.
- Increase in cardiac output: Cardiac output refers to the amount of blood pumped by the heart each minute. During pregnancy, the output increases by 30 to 40 percent because of the increase in blood volume.
- Increase in heart rate: It is normal for the heart rate to increase by 10 to 15 beats per minute during pregnancy.
- Decrease in blood pressure: Blood pressure may decrease by 10 mmHg during pregnancy. Such drop can be due to hormone changes and because there is more blood directed toward the uterus. Mostly, the decrease does not cause symptoms and no treatment is needed. Your healthcare provider will check your blood pressure during your prenatal appointments and will tell you if blood pressure changes are cause for concern.
If you have got a heart condition, such as those listed below, you should get yourself evaluated by a cardiologist (a heart specialist) and an obstetrician who specializes in high-risk pregnancy before you start planning a pregnancy.
- Hypertension (high blood pressure) or high cholesterol.
- Prior diagnosis of any type of heart or blood vessel disease, including aorta disease, arrhythmia, heart murmur, cardiomyopathy, heart failure, Marfan syndrome or rheumatic fever.
- Prior cardiac event (transient ischemic attack or stroke).
- Poor functional status, defined as NYHA class III or IV (shortness of breath with very minimal exertion). The New York Heart Association (NYHA) functional status is a set of clinical classifications that rank patients as class I-II-III-IV according to the degree of symptomatic or functional limits or cyanosis (a blue tint to the skin, lips and fingernail beds, indicates the body is not receiving enough oxygen-rich blood). For more information about this, ask your healthcare provider.
- Abnormal heart rhythm (arrhythmia/dysrhythmia).
- Severe narrowing of the mitral or aortic valve or aortic outflow tract (diagnosed using echocardiography).
- Ejection fraction less than 40%. Ejection fraction is the amount of blood pumped out of the left ventricle during each heartbeat. Your ejection fraction indicates how well your heart is pumping. A normal ejection fraction ranges from 50% to 70%.
The cardiologist will review your health history, perform a physical exam, and order diagnostic tests to check your heart function and the severity and extent of your condition. After reviewing the test results, the cardiologist will talk to you about how safe it is for you to be pregnant and the risk of complications during pregnancy, including potential short- and long-term risks to you and the baby. The cardiologist can tell you about any medications or other treatments you may need before pregnancy.
Be sure to discuss all of your medications (including heart medications and any over-the-counter medications you take routinely) with your doctor so your medication dosages can be changed if needed. You may also need to change medications to take those that are safer to take during pregnancy.
Dr. Usha Agarwal, Senior Consultant – Gynaecology, Narayana Multispeciality Hospital, Jaipur