Only about two out of five U.S. women who gave birth in 2019 had good heart health before their pregnancy, with overweight and obesity being the primary risk factors, followed by high blood pressure and diabetes, according to a study funded by the National Institutes of Health, the National Heart, Lung, and Blood Institute, and the American Heart Association (AHA). Their findings were published February 14 in the journal Circulation.
“Being in good health prior to pregnancy benefits the long-term health of women and their children,” said the lead study author, Natalie A. Cameron, MD, an internal medicine specialist and instructor at Northwestern University’s Feinberg School of Medicine in Chicago, in a press release.
“Unfortunately, these findings about the number of women with poor heart health prior to pregnancy are not surprising — heart disease is the leading cause of death for women in the U.S.,” says Rachel Urrutia, MD, an obstetrician-gynecologist and an assistant professor at the UNC School of Medicine in Chapel Hill, North Carolina, who was not involved in the research.
“This study includes overweight and obesity as cardiovascular risk factors, and we know those rates are rising,” says Dr. Urrutia.
From 1999–2000 through 2017–2018, the prevalence of obesity in U.S. adults increased from 30.5 percent to 42.4 percent, according to data from the National Health and Nutrition Examination Survey (NHANES).
The Number of Women With Good Heart Health Has Declined
To examine the prevalence of prepregnancy heart risk in the United States and compare geographic regions, investigators used data from the Centers for Disease Control and Prevention’s Natality Database from 2016–2019. A total of 14,174,625 people with live births were included; the women were between 20 and 44 years old, with 81.4 percent between ages 20 and 34.
The group was 52.7 percent non-Hispanic white, 22.7 percent Hispanic/Latina, and 14 percent non-Hispanic Black. Optimal heart health was defined as having a normal body weight with a body mass index (BMI) between 18 and 24.9 and not having hypertension or diabetes.
Researchers found the following trends:
- The overall percentage of women with optimal prepregnancy heart health went down more than 3 percent over the course of the three years, from 43.5 percent in 2016 to 40.2 percent in 2019.
- On average, heart health declined in older women — in 2019, the percentage of women with good heart health was 37.1 percent in women 40 to 44 years old and 42.2 percent among women 30 to 34 years old.
- More than half of all women had at least one risk factor for cardiovascular disease before becoming pregnant, and being overweight or obese was the most common reason for poor heart health before pregnancy.
Percentage of Women in Good Prepregnancy Heart Health Was Lower in the South and Midwest
Researchers compared data by geographical regions and found that the South and the Midwest had the lowest rates of good heart heath, at 38.1 and 38.8 percent respectively. States in the West and Northeast had the highest percentage of good heart health, at 42.2 percent and 43.6 percent respectively.
The researchers suspect these geographical differences are mostly fueled by social determinants of health, including factors like educational status, Medicaid enrollment, access to preventive care, the ability to afford healthy food, and the characteristics of the neighborhoods in which the women lived.
“These geographic patterns are, unfortunately, very similar to what we see for heart disease and stroke in both men and women, and they indicate that social determinants of health play a critical role in maternal heart health as well,” said the senior study author, Sadiya S. Khan, MD, an assistant professor of medicine in the division of cardiology at Northwestern University’s Feinberg School of Medicine in Chicago, in the release.
Poor Maternal Heart Health Can Lead to Poor Outcomes for Both Mom and Baby
“Pregnancy is nature’s stress test. There are many changes in the body during pregnancy, particularly the heart, including increased blood circulation, that put an extra burden on a woman’s heart,” said a coauthor of the American Heart Association’s Scientific Statement on Cardiovascular Consideration in Caring for Pregnant Patients, Garima V. Sharma, MBBS, the director of cardio-obstetrics and an assistant professor of medicine at Johns Hopkins School of Medicine in Baltimore, who was not involved in this study, in the release.
“Making sure you are in the best health you can be prior to getting pregnant will [ensure] you have the best pregnancy outcomes,” said Dr. Sharma.
Poor heart health puts both mothers-to-be and their children at risk, with heart disease causing more than one in four pregnancy-related deaths (26.5 percent) according to the American Heart Association’s Heart Disease and Stroke Statistics 2022 Update.
Out of 11 developed countries, the United States has the highest death rate for mothers, according to a November 2020 report sponsored by the Commonwealth Fund, a private foundation with a mission to improve quality and access for the most vulnerable in our population. The authors found that the maternal death rate was 17 deaths per 100,000 live births in 2018, more than twice the rate of most other high-income countries.
“We have increased rates of obesity, diabetes mellitus, and chronic hypertension relative to these other countries, which can certainly have an impact on the greater incidence of maternal death,” says Shari Martin Lawson, MD, the division director of general obstetrics and gynecology and an assistant professor of gynecology and obstetrics at Johns Hopkins Medicine in Baltimore.
Poor maternal health is also associated with poorer outcomes for babies at birth, says Urrutia. “For example, we know in women who have PCOS (polycystic ovary syndrome) and then get pregnant, the baby is more likely to have insulin resistance. Some of that may be related to genetics, but we also suspect it’s related to the in utero environment,” she says.
PCOS is caused by an imbalance of reproductive hormones which then creates issues in the ovaries. The condition is linked with other health issues including diabetes, high blood pressure, high LDL (bad) cholesterol and low HDL (good) cholesterol, sleep apnea, and depression and anxiety, according to the Office on Women’s Health.
Better Policies and Support Needed to Improve Women’s Prepregnancy Health
Given the impact of poor heart health on outcomes for both mother and baby, the researchers are calling for improvements in both national and local public health policies.
“We need to shift the conversation from solely ‘what can women do’ to what can society do to support mothers and pregnant individuals,” Dr. Khan said. “We need federal and state-level public health policies that ensure there is equitable access to care before, during, and after pregnancy, as well as economic investment in communities to support healthy behaviors, such as green spaces for exercise and access to heart-healthy food choices.”