Investigators at the Brigham have found that women who deliver a baby prematurely are at a significantly increased risk of developing cardiovascular disease later in life.
The study, published in Circulation on Feb. 2, in the American Heart Association’s “Go Red for Women” issue, found that women who delivered before 37 weeks were 40 percent more likely to develop cardiovascular disease, and their risk doubled if they delivered before 32 weeks.
Researchers also found that risks were higher among women who delivered more than one preterm infant. This was true after adjusting for age, race, parental education, pre-pregnancy lifestyle and cardiovascular disease risk factors.
“Delivering a preterm infant may be an early warning signal of high risk for cardiovascular disease,” said Lauren Tanz, MSPH, a programmer and data analyst in the Department of Medicine and the study’s first author. “Since cardiovascular risk develops over a lifetime, it’s not too early for these women to adopt a heart-healthy lifestyle.”
Researchers reviewed data on more than 70,000 women in the Nurses’ Health Study 2, examining the association between premature delivery and cardiovascular disease. The Nurses’ Health Studies are among the largest prospective investigations into the risk factors for major chronic diseases in women, following the health of female nurses around the country, including some at the Brigham.
“On average, 31 percent of female mortality in the U.S. is due to cardiovascular disease,” Tanz said. “If the risk that we saw among the relatively young nurses persists with age, we expect that 36 percent of women who give birth three to seven weeks early and 60 percent of women who deliver eight or more weeks before term will die from cardiovascular disease.”
Researchers are hopeful that this finding will help identify women who should be especially concerned about developing cardiovascular disease down the road.
“Very little of the risk associated with preterm delivery was explained by traditional cardiovascular risk factors like weight and hypertension,” said Janet Rich-Edwards, ScD, director of Developmental Epidemiology in the Connors Center for Women’s Health and Gender Biology and senior author of the research study. “We need more research to understand why women who deliver preterm are at higher risk and what we can do to help them lower it.”