A woman who is pregnant has her blood pressure taken at a doctor's office.

Pregnancy is like the ultimate stress test: what new prospective parents need to know about heart health

New research shows that by tending to their cardiovascular health now, patients can get big benefits during pregnancy and beyond

It’s important to keep hearts healthy at every life stage, but how people take care of themselves leading up to and during pregnancy can affect their cardiovascular health for decades. Victoria Pemberton, a nurse and researcher in the Division of Cardiovascular Sciences at NHLBI, shares updates about what parents-to-be and new parents can do to protect their hearts during this critical period of their lives.

Why is pregnancy viewed as a window into future cardiovascular health?

Fortunately, most people have healthy pregnancies. However, for every 10 people who give birth, about one to two experience a complication.

About half of pregnancy complications are related to high blood pressure. These complications include preeclampsia, which is a sudden spike in blood pressure; eclampsia, a preeclampsia complication that can lead to seizures; and also a condition called HELLP, which can affect the blood and liver.

When a patient experiences a severe pregnancy complication, such as preeclampsia, gestational diabetes, or a preterm birth, their risk for developing heart disease later in life can nearly double. This is one reason why pregnancy complications are considered independent risk factors for heart disease.

What can people do to reduce the risk of having a pregnancy complication?

About half of pregnancy complications can be prevented. One of the first things a patient can do is talk to their doctor about risk factors before and leading up to their pregnancy. This can include creating a plan to reach and maintain a healthy body weight, get blood pressure and blood sugar under control, and support physical activity or regular movement. It can also include ways to create meals around heart-healthful foods while quitting or avoiding tobacco.

Making this kind of plan could be lifesaving for a lot of patients, especially for those with risk factors for heart disease, such as elevated blood pressure, blood sugar, or blood cholesterol.

One study of almost 4,500 first-time parents found that that participants who had an adverse pregnancy outcome, such as preeclampsia, preterm birth, or low weight-for-age baby, also had increased associated risks for developing high blood pressure two to seven years after giving birth.

This study, the nuMoM2b Heart Health Study, like other similar studies, has helped underscore the power of prevention. What we know about high blood pressure is that the earlier you have it, the worse your outcomes for heart disease can be. If doctors and clinicians can partner with patients early to change that course, they have a much greater chance for helping patients reduce their risk for heart disease.

What else have researchers from the nuMoM2b Heart Health Study found? 

In addition to finding that women who experienced certain risks for cardiovascular disease during pregnancy were more likely to develop high blood pressure years later, researchers found that the severity of pregnancy complications also factored into these associations.

Women who had a preterm birth or a complication related to having high blood pressure during pregnancy were twice as likely to have high blood pressure two to seven years later compared to women who didn’t have complications. Additionally, more severe pregnancy complications were associated with up to a four-times greater risk.

First-time moms who had sleep apnea during pregnancy were also more likely to develop high blood pressure or other cardiovascular risks years after their pregnancy.

Physical activity appeared to have a protective effect. Participants who could stay active during pregnancy, even if this occurred during their second and third trimester, were less likely to have complications, including gestational diabetes or a preterm birth.

What are researchers still studying? 

One area of research is how an indicator for heart failure may help predict future pregnancy outcomes, but more research is needed to understand these connections.

Levels of NT-proBNP, a protein released from the heart when the muscle is overstretched, are often elevated among people with conditions like heart failure. In this case, researchers found the opposite was true for study participants who experienced a pregnancy complication related to having high blood pressure or who developed high blood pressure years after pregnancy. They had lower levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) during their first trimester. The links suggests that studying the way the heart and blood vessels respond during early pregnancy may be important.

Through ongoing nuMoM2b Heart Health Study research, investigators will study how pregnancy-related health outcomes may shape future risks for heart disease, vascular dementia, and other chronic conditions.

What should a patient tell their primary care doctor if they had a pregnancy complication?

One of the best things patients can do is share the details about that complication with their primary care doctor. When did it occur? How was it treated? What were the outcomes? A review in JAMA recommends routine cardiovascular screenings for patients three months after pregnancy complications and then annually.

The number of people experiencing health complications after pregnancy rises during the first year. Those three months after birth, which are often referred to as the “fourth trimester,” are critical for supporting a person’s overall health.

By working together with their doctor, a new parent has a better chance of reducing their risk for other conditions that have been linked to pregnancy complications: type 2 diabetes, stroke, early cognitive decline, and premature death.

Researchers are also studying ways physicians can better connect with patients during the months and year after they have a child. This includes thinking of ways to help patients, many of whom are busy with parenthood, receive ongoing monitoring and care.

This is critical when it comes to helping new parents who face challenges with receiving care, which could be due to geographic barriers, transportation, scheduling, or access.

Research has shown that pregnant people who are American Indian, Black, Hispanic, and Pacific Islander are more likely to experience adverse pregnancy outcomes, which exacerbates health disparities. What research might change these outcomes?

Pregnancy-related health disparities are staggering.

For example, Black patients are four times more likely to experience a severe event following preeclampsia compared to white patients. In 2020, researchers from across the NIH and other federal health institutes held a two-day workshop to discuss maternal health morbidity and mortality in the U.S.

With the support of the White House, researchers are studying a range of solutions to support patients before, during, and after pregnancy.

What are a few examples?

Right now, NHLBI is supporting two community-focused maternal health research initiatives.

One study, the Maternal Health and Community Implementation Project (CIP), will assess how different approaches – such as pre-pregnancy screenings and guided support – may improve the cardiovascular health outcomes of patients before and during pregnancy.

Another, the Early Intervention to Promote Cardiovascular Health of Mothers and Children (ENRICH), is also supported by the Health Resources and Services Administration, and will evaluate how community-supported partnerships may help patients after pregnancy. In this study, researchers will evaluate if bringing medical care to communities – through at-home medical visits – can improve the cardiovascular health of 3,000 new parents and their children.

The NIH, along with the Bill & Melinda Gates Foundation, has also awarded $1 million in prizes to researchers or teams who developed diagnostic tools created with the goal of improving pregnancy-related health outcomes and alleviating global health disparities.

Where can people go to learn more about pregnancy and heart health?

To learn about cardiovascular health and pregnancy, visit https://www.nhlbi.nih.gov/health-topics/education-and-awareness/heart-truth/listen-to-your-heart/heart-health-and-pregnancy.

This article was updated on June 26, 2023.