Women who have high-risk pregnancies or complications in childbirth are up to eight times likelier to suffer heart disease later in life. And many mothers — and their doctors — are unaware of the danger.

Emerging research shows heart disease is a long-term threat for women who develop diabetes or high blood pressure during pregnancy, for example, or those whose babies are born prematurely or precariously small.

Yet doctors do not typically advise women about their risk or counsel them to watch for symptoms, said Dr. Noel Bairey Merz, a cardiologist and director of the Barbra Streisand Women's Heart Center at Cedars-Sinai Heart Institute in Los Angeles.

She said doctors can see heart attacks and strokes coming, often 10 or 20 years ahead of time, if they are on the lookout.

"This isn't rocket science," she said. "We just have to figure out how we can find the women who are at risk."

Heightened awareness of the link between pregnancy complications and heart disease is prompting greater outreach to the public and collaborative research between cardiologists and obstetricians. That could help "make tremendous strides toward reducing and preventing heart disease in women," Bairey Merz said.

She and other researchers funded by the National Institutes of Health are tracking 5,000 new moms to fill gaps in knowledge about heart health and develop recommendations for physicians.

The Women's Heart Alliance, an advocacy group started by Cedars-Sinai and New York-Presbyterian Hospital/Weill Cornell Medical Center, also works with obstetricians and other providers to raise awareness among women and their doctors.

"We've got a big advocacy and education piece that we should be doing together," said Barbara Levy, vice president of health policy for the American Congress of Obstetricians and Gynecologists.

Levy said education is critical because it reduces the likelihood that women or their doctors will dismiss symptoms and concerns that should be taken seriously. Cardiologists and women's health care providers are in a unique position to drive the research agenda, Levy said. About 80 percent of U.S. women give birth to at least one baby, and one-fourth have complications during their pregnancies or labor.

Researchers are still trying to determine why such complications are linked to later heart problems. Among hypotheses: Pregnancy might contribute to vascular problems or unleash pre-existing tendencies.

"Pregnancy can really mimic the stressors of age," said Margo Minissian, a nurse scientist and researcher at the Cedars-Sinai Heart Institute. "Pregnancy could essentially be serving as a woman's first physiological stress test."

Minissian said that women who have had pregnancy or labor complications should tell their primary care doctors and have annual screenings for high blood pressure or other potential health problems. The American Heart Association and American Stroke Association recommend, for example, that women who have had pre-eclampsia — a potentially life-threatening spike in blood pressure during pregnancy — be evaluated for heart disease risk within a year of giving birth.

But most women who have had complicated pregnancies need not see a cardiologist right after giving birth, Levy said. They should just eat healthfully, be active and get enough sleep. Immediately referring all of these women to cardiologists could result in undue anxiety and unnecessary medical tests, she said. "It will cost a lot of money and a lot of her time while she is dealing with a baby."