Written by: Madison Estrella
Medically reviewed by: Rob Philibert MD PhD
Pregnancy naturally comes with physiological changes to an expecting mother’s body. These changes, such as increases in blood volume, cardiac output, heart rate and decrease in blood pressure, occur to help accommodate the growing fetus.
Although pregnancy and labor evoke some normal cardiovascular changes, there are some extra precautions that must be taken for women with pre-existing cardiovascular conditions and those experiencing unprecedented cardiovascular changes during pregnancy. These underlying conditions may lead to a higher risk for pregnancy complications. In fact, cardiovascular disease is one of the leading causes for pregnancy complications and constitutes 26.5% of pregnancy-related deaths in the U.S.  Being at risk for heart disease does not mean pregnancy is improbable. Rather, this risk warrants adequate preparation, knowledge and pre- and postnatal care.
High Blood Pressure During Pregnancies
Chronic hypertension is a particular condition that must be monitored during pregnancies. The American College of Obstetrics and Gynecology defines chronic hypertension in pregnancy as high blood pressure that is greater or equal to 140 mm Hg systolic / 90 mm Hg diastolic. This definition applies to pregnant women with pre-existing high blood pressure or those who develop high blood pressure before 20 weeks of pregnancy. Having high blood pressure can lead to arterial damage and plaque build up, which can negatively impact blood circulation. For pregnant women, having high blood pressure can mean decreased blood flow to the placenta, and thus less oxygen and nutrients going to the fetus.
Preeclampsia is a dangerous pregnancy complication characterized by high blood pressure, protein in the urine, and swelling in the arms and legs. According to Stanford Healthcare, 1 in 4 women with chronic hypertension develop preeclampsia during pregnancy, usually by mid-term.  Although the exact cause of preeclampsia is unclear, experts believe that the blood vessels supplying the placenta with blood narrow or do not develop properly. This would consequently limit blood flow to the fetus.
If left untreated, preeclampsia can have adverse implications on the mother and the baby. For the expecting mother, preeclampsia can lead to severe headaches, blurry vision, impaired liver function, and rapid weight gain caused by fluid retention. Pregnancy complications resulting from preeclampsia could include preterm birth and/or fetal growth restriction (slowed growth of the fetus).
In addition to high blood pressure, having diabetes and kidney disease can increase one’s risk for developing preeclampsia. Fortunately, the risk for developing preeclampsia can be reduced by following the proper medications and guidance provided by your doctor.
Heart Failure and Cardiomyopathies During Pregnancies
Another cardiovascular complication that may arise during pregnancy is heart failure and cardiomyopathies. Cardiomyopathies are defined as diseases that affect the heart muscle, which in turn, can compromise the heart’s efficiency in pumping blood, which may lead to heart failure. These conditions can be pre-existing in women with congenital cardiomyopathies, or caused by the extra stress the heart must endure during pregnancy and labor.
Peripartum Cardiomyopathy is a rare type of heart failure that can happen during pregnancy or immediately after delivery. It is generally characterized by the enlargement of the heart chambers and weakening of the heart muscle within the final month of pregnancy to five months after delivery. The change in elasticity of the heart’s muscle leads to less blood being pumped out of the left ventricle and into the body with each contraction. With less blood flowing through the body with each heartbeat, the heart is unable to supply the body with the oxygen and nutrients that it needs, which is also known as heart failure.
According to the American Heart Association, peripartum cardiomyopathy affects 1,000 to 1,300 women in the U.S. each year.  When diagnosing peripartum cardiomyopathy, doctors generally look for fluid in the lungs through an auscultation (listening for sounds in the heart and lungs using a stethoscope), which can also be used to identify abnormal sounds in the heart and rapid heart rate. Another key indicator of heart failure is a reduced heart function with an ejection fraction (amount of blood pumped out the left ventricle with each contraction) less than 45%, which is measured using an echocardiogram.
While heart disease can develop during pregnancy, pregnancy may also aggravate existing heart conditions in women with hereditary cardiomyopathies and other congenital heart defects. Congenital heart defects are changes in the heart’s structure that can affect people from birth. Women who have these conditions are also at a higher risk of heart failure and pregnancy complications for similar reasons as women who develop heart disease over time.
Planning for Pregnancy with Heart Disease
Women with congenital heart disease and risk factors for acquiring cardiovascular disease can still have a baby with proper preparation and care. It is highly encouraged that women with hypertension, high cholesterol, arrhythmias, a prior cardiac event (ex: heart attack or stroke) and/or diagnosis of cardiovascular disease should consult their cardiologist and obstetrician about the best course of action for a healthy pregnancy.
It is important to keep your heart in shape before and during your pregnancy to ensure that you and your baby are healthy and safe. Here are 5 basic things you can do to reduce your risk of cardiovascular complications during pregnancy:
- Keep up with your prenatal appointments with your obstetrician and cardiologist
- Eat a balanced, nutritious diet
- Exercise regularly
- Get enough sleep
- Do not smoke or vape
At the end of the day, it is very important for expecting mothers to maintain healthy habits. Their decisions can directly impact their own wellbeing and that of the baby.
- ACOG Practice Bulletin No. 212: Pregnancy and Heart Disease. (2019). Obstetrics & Gynecology, 133(5). https://doi.org/10.1097/aog.0000000000003243
- Pregnancy and High Blood Pressure. Stanford Health Care (SHC) – Stanford Medical Center. (2018, January 22). https://stanfordhealthcare.org/medical-conditions/womens-health/pregnancy-and-high-blood-pressure.html.
- Stergiopoulos, K., Lima, F. V., & Butler, J. (2019). Heart Failure in Pregnancy: A Problem Hiding in Plain Sight. Journal of the American Heart Association, 8(9). https://doi.org/10.1161/jaha.119.012905
- Peripartum Cardiomyopathy (PPCM). American Heart Association (n.d.). https://www.heart.org/en/health-topics/cardiomyopathy/what-is-cardiomyopathy-in-adults/peripartum-cardiomyopathy-ppcm.
- Heart Disease & Pregnancy. Cleveland Clinic. (n.d.). https://my.clevelandclinic.org/health/diseases/17068-heart-disease–pregnancy.