Pregnancy-Related CV Complications on the Rise

Among pregnant women, the prevalence of preexisting cardiometabolic comorbidities and CVD, as well as rates of pregnancy-related CV complications, are high and have been trending upward over the past few decades, a cohort study shows.

Between 2001 and 2019, the age-adjusted incidence of CV complications occurring between the end of the first trimester and the first postpartum year increased from 11% to 13% (P < 0.001), driven primarily by an uptick in hypertensive disorders of pregnancy, researchers led by Emily Lau, MD (Massachusetts General Hospital, Boston), report in a paper published online this week in Circulation.

Women with a heavier burden of preexisting comorbidities and CVD were more likely to develop complications during pregnancy, with non-Hispanic Black women faring the worst.

“These data are not necessarily altogether surprising, but they’re sobering,” Lau told TCTMD, noting that cardiometabolic risk factors like obesity, diabetes, hypertension, and hyperlipidemia have grown more common over the past few decades across the population.

The main takeaway from the study “is that pregnancy is an opportunity . . . for us to really think about optimizing cardiovascular health for women who are often younger and maybe in a group of people that we’re not necessarily thinking as high risk or thinking about their cardiovascular risks,” Lau said.

Prior research has shown that CV health in the context of pregnancy has been deteriorating over the past several decades. Cardiovascular complications are a major cause of maternal morbidity and mortality, and that’s on the backdrop of the United States having the highest maternal mortality rates of all industrialized nations.

“In recent years, we’ve really come to realize the gravity of maternal morbidity and mortality in this country,” said Lau, who, as a women’s heart health specialist, sees many patients who have cardiometabolic risk factors or overt CVD and who are pregnant or thinking about becoming pregnant.

“It’s really important to me and to physicians like me that we can ensure that these women get the absolute best care, so that we can really change the tide on what really shouldn’t be a public health crisis,” she said, adding that the Centers for Disease Control and Prevention has estimated that more than 80% of maternal deaths are preventable. “That means if there’s something that we can actually do to help these patients to avoid maternal mortality and morbidity, then we’ve got to be doing it.”

Lau and her colleagues say there’s a need to better understand the contemporary burden of CVD in pregnancy to identify high-risk individuals, citing a dearth of large cohort studies with robust CV outcomes data for pregnant women.

Optimizing CV Health Before Pregnancy

To help fill that gap, the investigators developed a pregnancy cohort—called PADME—derived from a primary care electronic health record database within the Mass General Brigham healthcare network, which includes 11 tertiary care and community hospitals in New England. They included 56,833 pregnancies among 38,996 women ages 18 to < 60 years (mean age 32 at the start of pregnancy) between 2001 and 2019.

Lau said her team was able to pull together such a large cohort of pregnant women by applying machine-learning approaches, including natural language processing and large language models, to extract data from charts in the electronic medical records.

Cardiometabolic comorbidities were common, with preexisting obesity in 12% of pregnancies, hyperlipidemia in 10%, hypertension in 8%, and diabetes in 3%. These proportions increased over time after adjustment for age. The highest rates of obesity, hypertension, and diabetes were observed in non-Hispanic Black women, with white women being most likely to have preexisting hyperlipidemia at the time of pregnancy.

Preexisting overt CVD was present in 4% of pregnancies. Age-adjusted prevalence rose from 1% in 2001 to 7% in 2019 (P < 0.001). CVD was most common in women older than 40 years versus their younger peers and was more frequent in Black and white women than those from other racial/ethnic groups.

The overall incidence of pregnancy-related CV complications—a composite of maternal death, MACE, and hypertensive disorders of pregnancy assessed from the end of the first trimester through 1 year postpartum—was 15% (age-adjusted 17%). Most of these events (84%) occurred before delivery, with the rest occurring during the first postpartum year. The rate of hypertensive disorders of pregnancy was 12% and the MACE rate was 4%; there were only five maternal deaths (0.01%). Complications were most frequent among Black women throughout the study period.

CV complications were more likely to occur among women with a greater burden of cardiometabolic comorbidities or overt CVD, “highlighting prepregnancy cardiovascular health optimization as a key provision needed to improve maternal outcomes,” Lau et al write.

Overall, the researchers say, “we demonstrate that the contemporary real-world burden of maternal cardiometabolic risk factors and subsequent pregnancy-related cardiovascular complications are rising in parallel with considerable racial and ethnic disparities and underscore pregnancy as a crucial window of opportunity to optimize cardiovascular health.”