Women who breast-feed their babies may have a healthy heart, a new study suggests.

Researchers at the University of Pittsburgh examined 297 women who had had at least one baby. At the time of the study, they were 45 to 58 years old, had never been diagnosed with heart disease and had no known symptoms of heart disease.

The researchers used two imaging techniques - electron beam tomography and ultrasound - to assess the health of the women’s blood vessels.

They found that 32 percent of the women who had not breast-fed had coronary artery calcification, compared with 17 percent of the breast-feeding moms. For those who had not breast-fed 39 percent had calcifications in the aortas, versus 17 percent of the women who breast-fed. The researchers also found plaque deposits in the carotid artery of 18 percent of the women who had not breast-fed and 10 percent of those who had.

After adjusting the data for socioeconomic status, family history and lifestyle factors, heart disease risk factors and body mass, the researchers concluded that women who had not breast-fed were five times more likely to have aortic calcifications than women who consistently breast-fed.

The researchers suspect that the apparent benefit from breast-feeding on later heart health stems from how a woman’s body stores fat and how that fat is released - or not released - after pregnancy.

“A woman’s body expects to go through pregnancy and then lactation,” said the study’s lead author, Dr. Eleanor Schwarz, an Assistant Professor at the University’s Center for Research on Health Care. “During pregnancy, a woman’s body stores fat that it expects to release during lactation. If women don’t breast-feed, then the body has to deal with excessive fat.” Eleanor added. The bottom line is that it is really important to try to breast-feed, she said. “If you can breast-feed for three months after each pregnancy, your blood vessels are likely to be in better shape down the road.” Eleanor said. Results of the study were published by HealthDay News on Monday.