Mothers who breastfeed for at least six months may have a lower risk of developing high blood pressure, a new study shows.
The findings, published in the American Journal of Epidemiology, add to evidence that breastfeeding might have benefits for mothers.
However it does not prove that breastfeeding is the direct cause of the healthier blood pressure, researchers said.
Breastfeeding is thought to help protect babies against common ills, such as diarrhoea and middle-ear infections, and previous studies have found that women who breastfeed have lower risks of diabetes, high cholesterol and heart disease later in life.
"Women who never breastfed were more likely to develop hypertension than women who exclusively breastfed their first child for six months or more," wrote lead researcher Alison Stuebe.
In general, experts recommend that babies be breastfed exclusively for their first six months, then continue getting breast milk along with solid food until they are a year old.
Dr Stuebe said that none of the findings proves that breastfeeding itself gives long-term protection against high blood pressure, but it's also plausible that breastfeeding has direct benefits, she added.
Research has found the hormone oxytocin, which is involved in breastfeeding, has lasting effects on blood pressure.