Past studies have shown a link between cardiovascular disease and the number of times a woman has given birth. But giving birth as a teenager may also pose heart-related risks to mothers later in life, a new study suggests.

The study, published Wednesday in the Journal of American Heart Association, found that postmenopausal women who had their first child before age 20 had a higher risk for cardiovascular disease compared to women who had children later in life or had no children.

The findings could have serious implications for public health policy and for the way doctors treat women who gave birth as teens.

“Adolescent childbirth may serve as a risk marker for cardiovascular disease,” said study author Catherine Pirkle, Ph.D., a University of Hawaii at Manoa assistant professor in public health.

“Women who were adolescent moms may need to be more proactive about their cardiovascular health, and clinicians might need to have conversations with women about their childbirth history and also be more careful about cardiovascular screening and follow-up,” she said.

The study examined data collected in 2012 from the International Mobility in Aging Study, focusing on 1,047 women ages 65 to 74 living in Canada, Brazil, Albania and Colombia. Researchers compared the Framingham Risk Score – which measures cardiovascular risk – of women who had their first child before age 20 with the score of women in several other categories, including those who had children later in life and those who had multiple childbirths. The results showed that adolescent mothers had a higher risk compared to women in the other categories.

According to the World Health Organization, 11 percent of all children worldwide are born to teens ages 15 to 19. While specific percentages in the U.S. aren’t available, the Centers for Disease Control and Prevention reports the birth rate among 15- to 19-year-olds dropped 8 percent between 2014 and 2015, down to 22.3 births per 1,000 women in this age group.

The new study showed that women who had their first child before age 20 were more likely to have grown up in lower-income families, under adverse social conditions, and with less education.

Having an adolescent birth often denies women the opportunity for education and career development, which may lead to greater stress and financial adversities,” said JoAnn Manson, M.D., Dr.P.H., a professor of medicine and women’s health at Harvard Medical School and the chief of preventive medicine at Brigham and Women’s Hospital in Boston.

Manson, who wasn’t involved in the study, said the research is an important step in women’s health. But she also called for further studies to look at what other factors might cause adolescent mothers to experience higher risks for cardiovascular disease.

“We need a deeper evaluation of the prevalence of cigarette smoking, lack of physical exercise, poor diet, as well as psychosocial stressors,” she said.

Pirkle agreed, and said “the jury’s still out on whether adolescent childbirth is a causal factor. A lot more work still needs to be done to figure out if it’s purely physiological, or is it something about the social circumstances under which women live.”

The study also showed that women who had no children had the lowest risk scores of all – a finding that contradicts some earlier studies.

Pirkle stressed that these findings do not suggest motherhood at any age is unhealthy. The overall message behind the study, she said, “is that we should look at the broader question of how do we take care of our mothers? How do we give them the social support to engage in healthy behaviors?”

The study also serves as a reminder that “adolescent childbearing is generally viewed as undesirable, both in the U.S. and in most global settings,” Pirkle said. “Our results simply reinforce that view at a moment in time when women’s reproductive rights are being eroded across the U.S., especially regarding access to contraception, which is so important to preventing adolescent pregnancy.”

Manson concurred. “Not to get too political about it, but it really does support the importance of having contraception be accessible to women and providing societal support to women who do have a first birth at an early age,” Manson said. “Whether it’s through government programs or social support or family efforts, that support is tremendously important.”

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