Underlying cardiovascular risk, rather than older age, drives complications such as venous thromboembolism, cardiomyopathy and heart failure during pregnancy, according to new Weill Cornell Medicine research. The findings may encourage doctors to more actively address cardiovascular health in patients before they become pregnant.
The study, published May 18 in Nature Communications, suggests that instead of pregnancy becoming inherently riskier as people get older, it amplifies a person’s baseline cardiovascular risk, regardless of age.
“Pregnancy seems to be a uniform stress test, so to speak,” said the study’s lead author, Dr. Hooman Kamel, vice chair of clinical research and chief of neurocritical care in the Department of Neurology and the Helen and Albert Moon Professor of Neurology at Weill Cornell Medicine.
Dr. Hooman Kamel
Pregnancy-related cardiovascular complications account for 20% to 30% of maternal deaths in the United States. However, the relationship between age and risk of these complications has been unclear, said Dr. Kamel, who is also a neurologist at NewYork-Presbyterian/Weill Cornell Medical Center.
The Study Data
The researchers analyzed deidentified claims data on hospitalizations across 11 states between 2016 and 2021 and identified 2,710,983 patients with a first pregnancy. Patients acted as their own controls, with researchers comparing cardiovascular events during pregnancy and the postpartum period against an equal period one year later.
“We took advantage of the fact that pregnancy is a time-limited risk factor, and this helped us disentangle the issue of baseline risk versus the risk of the pregnancy itself,” said Dr. Kamel, who is also director of the Clinical and Translational Neuroscience Unit and a professor of neuroscience in the Feil Family Brain and Mind Research Institute at Weill Cornell Medicine.
Of 13,744 patients who had a major adverse cardiovascular event, 12,059 experienced it during pregnancy or the postpartum period, compared to 1,685 during the control phase of the study.
Venous thromboembolism, cardiomyopathy and heart failure were the most common events. Cerebrovascular events such as brain hemorrhages and strokes were rarer, “but when they happen, they’re devastating and disabling,” Dr. Kamel said.
Of those with a major adverse cardiovascular event, 240 died. Among the survivors, close to 10% needed care at a rehabilitation or nursing facility or needed home healthcare.
Overall, pregnancy and the postpartum period were associated with seven times the risk of major adverse cardiovascular events compared with the control period, agreeing with prior studies. However, this risk increase, relative to patients’ baseline, did not vary with maternal age.
About three excess cardiovascular events occurred per 1,000 pregnancies until age 31. This number steadily increased and reached 10 excess events per 1,000 pregnancies by age 44. “Patients who were older had more vascular events, but this is really a reflection of their baseline risk,” Dr. Kamel said.
Black patients were more likely to experience cardiovascular events than white patients; however, their risk did not vary with age. “This finding suggests that there are other factors at play such as social determinants of health and access to risk factor management,” Dr. Kamel said.
Implications for Patients and Doctors
The study suggests that addressing cardiovascular health before pregnancy could reduce baseline risk, Dr. Kamel said. “A 40 year old who is very healthy coming into pregnancy with a low cardiovascular risk may be better off than a 25 year old who has higher cardiovascular risk,” he said.
Dr. Laura Riley. Credit: Brad Trent
“This study highlights that obstetricians and gynecologists should investigate signs and symptoms of cardiovascular disease in all women prior to and during pregnancy rather than assume that youth is a protective factor,” added co-author Dr. Laura Riley, chair of the Department of Obstetrics and Gynecology and executive director of women’s health at Weill Cornell Medicine and obstetrician and gynecologist-in-chief at NewYork-Presbyterian/Weill Cornell Medical Center.
Doctors are adopting more aggressive guidelines for managing blood pressure and cholesterol. “I think there’s a growing appreciation for checking these risk factors in young adulthood,” Dr. Kamel said. “And certainly, given how much pregnancy amplifies that risk, this is even more crucial.”
Many Weill Cornell Medicine physicians and scientists maintain relationships and collaborate with external organizations to foster scientific innovation and provide expert guidance. The institution makes these disclosures public to ensure transparency. For this information, see profile for Dr. Hooman Kamel and Dr. Laura Riley.
