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Pregnancy: The ultimate stress test for the heart

By The Health News Team | January 4, 2023
Pregnant woman getting her blood pressure read

The average healthy pregnancy lasts about 280 days or 40 weeks. During that time, a woman’s body will go through a multitude of significant changes. Some are easy to see, such as a growing baby bump. But there are also less visible changes, including those that involve the heart.

“Pregnancy can be very demanding on a women’s cardiovascular system, and frequently, it’s referred to as the ultimate stress test for a woman’s heart,” says Dr. Deirdre McCullough, a board-certified maternal fetal medicine specialist affiliated with Sharp Grossmont Hospital.

According to Dr. McCullough, cardiovascular disease is the number one cause of maternal death among American women. “Maternal cardiac disease complications make up a small percentage of pregnancies overall, but it is the leading cause of pregnancy-related deaths,” she says.

Dr. McCullough explains some of the changes that impact the heart when someone is pregnant, reviews common heart-related complications and offer tips for staying heart healthy.

What happens during pregnancy to make the heart work harder?
Many changes occur in the cardiovascular system to help nourish a growing baby and ensure the baby receives enough oxygen and nutrients for a healthy delivery.

  • Cardiac output — In the first trimester, cardiac output, or the amount of blood the heart pumps per minute, increases by 30% to 50%. The changes peak in the second trimester and remain for the remainder of pregnancy. Once in labor, cardiac output increases an additional 30%.

  • Blood volume — Blood volume increases by 150% over nonpregnant levels. Blood volume is composed of plasma and red blood cell mass.

  • Heart rate — The heart rate rises 15% to 20% in the third trimester. During labor, pulse surges 40% to 50% with contractions.

  • Blood pressure— Typically, blood pressure decreases in the first and second trimesters — down 10% and 5%, respectively, with a slight 5% increase in the third trimester. During labor, blood pressure readings elevate and fluctuate slightly after delivery, then return to normal in postpartum.

What common heart-related issues may develop during pregnancy?
Even healthy people can have unexpected complications during pregnancy, and the causes are not always clear. Getting regular prenatal care can identify problems early for better outcomes. And receiving post care reduces risk of cardiovascular problems that can occur later in life, including:

  • Gestational hypertension — High blood pressure may occur in about three out of 50 women, usually in the second half of pregnancy. It normally goes away after the baby is born.

  • Preeclampsia — A serious condition that can occur after 20 weeks of pregnancy, preeclampsia symptoms range from high blood pressure and protein in the urine to swelling, headaches and blurred vision. Once the baby is born, it typically goes away.

  • Gestational diabetes — Women who develop gestational diabetes, a form of high blood sugar in pregnant women, are at risk of developing Type 2 diabetes later in life.

  • Fetal growth restriction — There are several causes for this condition, in which an unborn baby is smaller than expected. But the most common is a problem with the placenta, which is the tissue that carries oxygen, nutrients and blood to the baby.

  • Low birth weight — An infant born weighing 5 1/2 pounds or less is considered to have low birth weight. Most commonly, it can occur when an infant is born too early or is affected by fetal growth restriction.

  • Obesity— Having a high body mass index (BMI) of 30 or higher can cause heart-related complications from miscarriage to gestational diabetes.

What heart-healthy pregnancy tips can you offer?

  • Eat a healthy diet. Stay on the outside aisles of the grocery store. Start in fresh fruits and vegetables, circle around to the dairy section and choose low fat options. Drop by the lean meats and fish sections, then head out.

  • Start doing cardiovascular exercise. The American College of Obstetricians and Gynecologists suggests getting at least 30 minutes or more of moderate exercise per day. Check with your OBGYN before starting a new exercise routine.

  • Reduce stress. Life stressors can negatively impact a pregnant person’s wellbeing as well as increase the risk of adverse pregnancy outcomes and cardiovascular disease. Use healthy coping mechanisms such as meditation. It is easy, and multiple studies show it to be effective at relieving stress.

  • Connect with friends and family. Positive interactions increase levels of oxytocin, also known as the “love hormone,” which can reduce stress and blood pressure. Socializing also reduces the hormone cortisol, which can negatively impact our body.

  • Get prenatal care, especially if you have a preexisting heart condition. See your primary care doctor and a specialist to screen for development or treatment of hypertension, hyperlipidemia and diabetes. Early interventions improve outcomes.

  • Get postpartum care. A primary care doctor, a cardiologist, or an endocrinologist can help to manage your long-term health, start medications as needed, and perform interventions if you have a history of heart disease or developed a condition during pregnancy.

  • Avoid alcohol. Alcohol is never safe in pregnancy or during breastfeeding. Outside of pregnancy, women should minimize their alcohol intake to no more than one drink per day.

To learn if you qualify to receive heart-related services after giving birth, call the new Postpartum Heart Health clinic at Sharp Grossmont Hospital’s Burr Heart & Lung Clinic at 619-740-4770.

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