What Pregnancy Does to Your Heart
Key Takeaways:
Pregnancy significantly increases cardiovascular demand, including a 10–20 bpm rise in resting heart rate, a 30–50% increase in blood volume and a 30–50% increase in cardiac output between weeks 28 and 34. Common pregnancy-related cardiac symptoms include fatigue, shortness of breath, heart palpitations, and heart murmur. Pre-existing conditions such as congenital heart disease, heart valve disease, and cardiomyopathy can increase the risk of complications during pregnancy. Even without prior heart disease, pregnant women may develop gestational hypertension, arrhythmias, gestational diabetes or deep vein thrombosis, with pregnant women being 4–5 times more likely to develop blood clots. Protective measures include maintaining a healthy weight, exercising safely, prioritizing sleep, and attending all perinatal appointments.
Mother’s Day is rapidly approaching, and our team at South Denver Cardiology would like to take a moment to celebrate all the mothers in our community. We’d also like to provide some important educational information to soon-to-be mothers regarding how pregnancy impacts their heart. Pregnancy creates a variety of changes in your body, and some of these result in added strain on your heart.
The good news is that the normal changes to your cardiovascular system are temporary, and your heart function will return to its pre-pregnancy state within a month or two of giving birth. But there are some instances where complications associated with the changes to your heart can interfere with your pregnancy or have a long-term impact on your health. If you currently have a heart condition or are prone to heart disease, it’s especially important to work with a cardiologist throughout your pregnancy to ensure you don’t experience any adverse heart issues.
How Pregnancy Affects the Heart
During pregnancy, your heart must pump extra blood to your uterus to support the developing baby. This places additional strain on your cardiovascular system, as it works harder to support the additional blood volume pumping through your body. It’s common to experience the following changes to your heart as your pregnancy progresses:
- Increase in Heart Rate – Your resting heart rate will often increase 10 to 20 beats per minute during pregnancy. This increase typically occurs gradually, with your heart rate reaching its highest level in your third trimester.
- Increase in Blood Volume – Your blood volume will start increasing during the first few weeks of pregnancy and continue rising as you progress towards childbirth. It’s common for blood volume to increase 30-50% during pregnancy.
- Fluctuations in Blood Pressure – Hormonal changes in the early stages of pregnancy will cause your blood pressure to initially go down. This can cause mild dizziness or weakness in your first or second trimester. Between weeks 24-26, your blood pressure will begin to rise through the duration of your pregnancy. It’s important to have your blood pressure monitored during your third trimester since extremely elevated numbers or a rapidly rising blood pressure could be a sign of gestational hypertension, a serious complication that can increase your risk of stroke or kidney failure.
- Increase in Cardiac Output – Cardiac output refers to the amount of blood pumped by your heart each minute. It’s common to experience a 30-50% increase in cardiac output between weeks 28 and 34, and this figure is often higher if you’re pregnant with twins.
- Increased Muscle Mass – Your heart may build new muscle mass during pregnancy due to the increase in heart rate, blood volume and cardiac output.
Common Symptoms Caused by Changes to Your Heart During Pregnancy
The increased strain on your heart during pregnancy can result in a variety of symptoms, including:
- Fatigue
- Shortness of breath
- Dizziness or lightheadedness
- Irregular heartbeat
- Heart palpitations
- Heart murmur
While these symptoms are normal, they also overlap with some symptoms of heart disease. This can make it hard to determine whether your symptoms are just part of being pregnant or a cause for concern. If you’re at all uncertain about whether these symptoms are a warning sign of heart disease, it’s best to consult with a cardiologist.
Pre-Existing Heart Conditions That Can Affect Your Pregnancy
Heart disease can increase your risk of complications during pregnancy or reveal problems that had previously been undiagnosed. If you have any of the following conditions, you should talk to a cardiologist about any potential risks associated with becoming pregnant:
- Congenital Heart Disease – Congenital heart disease refers to problems with your heart that develop before birth. Congenital heart conditions can increase your risk of an irregular heartbeat (arrhythmia) or heart failure during pregnancy. You may also be at higher risk of premature birth.
- Heart Valve Disease – There are many different types of heart valve disease and while some won’t impact your pregnancy, others may increase your risk of complications. If you have heart valve disease, discuss your pregnancy plans with your cardiologist to make sure you won’t face any serious health risks.
- Cardiomyopathy – Cardiomyopathy is the leading cause of serious heart complications during pregnancy. This condition makes it harder for your heart to pump blood throughout your body, and it can increase your risk of heart failure during pregnancy.
Potential Heart Issues That Can Develop During Pregnancy
Even if you have no prior history of heart disease, it’s possible to develop one or more of the following conditions during pregnancy:
- Gestational Hypertension – High blood pressure that often begins after 20 weeks of pregnancy
- Arrhythmias – Pregnancy can increase your risk of an irregular heartbeat, even if you have no prior history of arrhythmias
- Gestational Diabetes – Some women will see their blood sugar spike after 20 weeks of pregnancy, requiring treatment to minimize the risk of complications for both the mother and baby
- Deep Vein Thrombosis (DVT) and Pulmonary Embolisms – Pregnant women are 4-5 times more likely to develop DVT (blood clots in a leg vein) or pulmonary embolism (blood clot that travels from its point of origin to your lungs)
How to Protect Your Heart During Pregnancy
There are steps you can take to protect your heart during your pregnancy. While these tips are important for all women, they are especially important if you have a pre-existing heart condition:
- Consult Your Cardiologist if You Have Pre-Existing Heart Conditions – If you have a heart condition, it’s critical to consult with your cardiologist before becoming pregnant to make sure your heart can handle the changes that will occur during pregnancy. In some instances, you may need to make adjustments to your medications to ensure your body can safely carry a baby.
- Maintain a Healthy Weight – It can often be challenging to eat a healthy diet during pregnancy due to nausea, morning sickness and other common symptoms you’ll experience. But it’s critical that you maintain a healthy weight throughout your pregnancy. Talk to your doctor at the start of your pregnancy to find out the appropriate weight gain range based on your pre-pregnancy weight. This is critical to help prevent conditions such as gestational diabetes and gestational hypertension from developing.
- Exercise Safely – Continuing to exercise during your pregnancy is important to keep your body in shape and help you manage your weight, but it’s important to engage in activities that will be safe. Your heart is under greater strain during pregnancy, so you may need to adjust the exercises in your workout, as well as the duration and intensity levels of your workouts, to ensure you’re not overworking your heart.
- Get Plenty of Sleep – It’s important to get on a regular sleep schedule when you’re pregnant. If you’re struggling to sleep through the night, ask your doctor about any lifestyle adjustments you can make to improve your sleep quality throughout your pregnancy.
- Listen to Your Body – It’s common to experience fatigue from the increased cardiac output and hormonal changes that occur during pregnancy. Take breaks from strenuous activities when you feel tired, and try to nap if you’re exhausted. This can help reduce your risk of pregnancy-related heart complications.
- Attend All Your Perinatal Appointments – One of the most important steps you can take to protect your heart health during pregnancy is to attend all your perinatal appointments with your OBGYN. During these appointments, discuss any changes you notice with your body to ensure potential complications are addressed right away.
South Denver Cardiology Can Help Manage Your Heart Health During Pregnancy
If you have a heart condition, South Denver Cardiology can help you manage your heart health during pregnancy. We have a cardio-obstetrics doctor on staff, Dr. Josephine Chou, who has extensive experience working with pregnant women with heart conditions. Prior to joining South Denver Cardiology, Dr. Chou established and ran the cardio-obstetrics program at Yale University for five years. During this time, she provided pregnancy-related care for pregnant patients with cardiovascular disease. She has continued that work since moving to Colorado. She served as director of cardio-obstetrics at the University of Colorado from 2022-2024, and she’s been the staff cardio-obstetrics physician at South Denver Cardiology since joining our team in February 2024.
Contact us today to schedule an appointment. South Denver Cardiology serves patients in Denver, Littleton and the surrounding areas.
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