New mothers who successfully breastfeed their babies are less likely to get postnatal depression, new research suggests.
Expectant mothers who plan to breastfeed after they have given birth but are unable to are at the highest risk of developing the condition, experts found.
Around 13% of new mothers experience postpartum depression within 14 weeks of giving birth. As well as posing serious mental health problems for the mother it can also have significant affects on the newborn's cognitive, social and physical development, researchers said.
They said that the effect that breastfeeding has on postnatal depression is not well understood and set out to investigate whether there is a link between the two.
The authors, from the UK and Spain, surveyed women who had almost 14,000 babies in the Bristol area during the 1990s when their children were two, eight, 21 and 32 months old.
"Breastfeeding has well-established benefits to babies, in terms of physical health and cognitive development. Our study shows it also benefits the mental health of mothers," said Dr Maria Iacovou, from the University of Cambridge's Department of Sociology.
"For mothers who were not depressed during pregnancy, the lowest risk of postpartum depression was found among women who had planned to breastfeed, and who had actually breastfed their babies, while the highest risk was found among women who had planned to breastfeed and had not gone on to breastfeed," the authors wrote.
This link was found to be most pronounced when the babies were two months old but much smaller by the time they were eight months or older, they added.