Previous research has found that breastfeeding could reduce a woman's risk of ovarian and breast cancer, and osteoporosis.
The UK has one of the lowest breastfeeding rates in Europe, with almost one in three new mothers never attempting it.
What is the research?
The findings are based on a study of 139,681 postmenopausal women with an average age of 63 years.
Women were asked whether they had breastfed their child and for how long. They were then followed over eight years for any signs of CVD.
Women who breastfed for at least one year reduced their risk of developing heart disease or suffering a stroke by 10 per cent compared with women who had never breastfed.
Breastfeeding also cut the risk of developing hypertension by 12 per cent.
The researchers noted that, as it had been 35 years on average since the women had last breastfed, the health benefits appeared to last for decades.
They proposed that breastfeeding may reduce CVD risk by mobilising fat stores that accumulate during pregnancy.
What do the researchers say?
Lead researcher Dr Eleanor Schwartz, from the University of Pittsburgh, said: 'Studies have shown that women are more likely to breastfeed if they believe their doctors think it's important for them to do so.
'Breastfeeding is a health behaviour that primary care doctors need to encourage and support, the same way we encourage our patients to be active, eat well, and avoid tobacco.'
Dr Schwarz added that GPs should encourage mothers to ask for help if they find it hard to breastfeed.
'Breastfeeding is like riding a bike, it can be tricky at first, and almost everyone needs a little bit of help getting started, but it's really important to learn how to do it.'
What do other researchers say?
June Davison, cardiac nurse at the British Heart Foundation, said: 'Breastfeeding has long been thought to be beneficial to baby and mother. This research suggests that it might also have heart health benefits for mum.
'However, it only showed an association between breast feeding and these health benefits.' Further research will be needed to understand why this is the case, she said.
- Obstetrics and Gynaecology Online 2009
- Mothers who breastfeed can lower their risk of suffering a heart attack or stroke.
- The health benefits of breastfeeding appear to be retained for decades after the mother has stopped lactating.
- Researchers suggest that breastfeeding may reduce women's CVD risk by mobilising fat stores that accumulate during pregnancy.