LONDON, Aug. 21 (Xinhua) -- A new study of over 10,000 mothers has shown that women who breastfed their babies were at significantly lower risk of postnatal depression than those who did not.

The study, by researchers in Britain and Spain, was published on this week's British scientific journal Maternal and Child Health.

It used data of 13,998 births in Britain in the early 1990s. Maternal depression was measured when babies were eight weeks, and eight, 21 and 33 months old.

Depression was also assessed at two points during pregnancy, enabling the researchers to take into account mothers' pre-existing mental health conditions.

It showed that mothers who chose to breastfeed were around 50 percent less likely to become depressed than mothers who did not.

According to researchers, the relationship between breastfeeding and depression was most pronounced when babies were eight weeks old.

"Breastfeeding has well-established benefits to babies, in terms of their physical health and cognitive development," research leader Maria Iacovou from Cambridge University said. "Our study shows that it also benefits the mental health of mothers."

The expert added that, the effects on mothers' mental health are also likely to have an impact on babies, since maternal depression has previously been shown to have negative effects on many aspects of children's development.