Pregnancy causes profound changes in your body, including ones that affect your heart as your body works to produce and supply enough blood to keep your developing baby healthy. During the first 5-8 weeks of pregnancy, the total amount of blood in your body will increase by 40-50 percent, which has a number of effects:
- Your body’s blood volume (the amount of fluid) increases.
- Your heart has to pump faster to move the added blood through. This typically translates to about 10-15 beats faster per minute.
- Your body’s blood pressure drops by about 10 mmHg as blood vessels dilate.
- The extra blood flow can cause a slight heart murmur, although it is not typically cause for concern.
In some instances, however, blood pressure can increase to high levels during pregnancy, a condition known as gestational hypertension. High blood pressure during pregnancy is also associated with a condition called preeclampsia, which can affect your heart and increase the likelihood of pregnancy complications. To make sure your heart is healthy, you will have a blood pressure check at every prenatal visit.
While these changes can seem daunting, remember that cardiac-related complications due to pregnancy are rare in women who didn’t have a cardiac condition prior to becoming pregnant. Between 1 and 4 percent of pregnant women have cardiac-related complications. However, you should be aware of symptoms that could signal a problem, including:
- Chest ache, heaviness, or discomfort
- Heart palpitations where your heart feels like it’s racing or beating irregularly
- Lightheadedness or dizziness
- Shortness of breath that worsens with time, especially if it occurs at rest or is limiting your physical activity
Tell your provider immediately if you experience these symptoms. If your symptoms are severe or include chest pain, seek immediate medical attention.
What if you do have a pre-existing heart condition? If you have been diagnosed with a heart or heart-related condition, such as rhythm issues, heart valve disorders, congestive heart failure, high blood pressure, or congenital heart defect, it is best to discuss your plans for becoming pregnant with your obstetrician and a cardiologist before you get pregnant. This is especially true if you have heart conditions that could have life-threatening consequences if you were to become pregnant, such as Eisenmenger’s syndrome or aortic or mitral valve disease.
Reviewed by Dr. Jen Lincoln, November 2018
- Increased blood volume during pregnancy can affect how hard you heart works.
- Your heart rate typically increases by about 10-15 beats per minute while your blood pressure drops by 10 mmHg.
- If you have a heart condition, notify your physician before becoming pregnant so you can discuss risks and treatment options during pregnancy.