Mothers who cradle their babies to their right-hand sides are displaying signs of extreme stress, a new study suggests.

Although most new mothers feel stressed in the early stages of their babies' lives, the study by U.K. researchers finds that baby-cradling habits are a key indicator of whether this stress could become overwhelming and lead to depression.

Previous research has shown that the majority of mothers prefer to cradle their baby to their left regardless of whether they are left- or right-handed, the study from Durham University offers as background.

The research, published in the online version of the Journal of Child Psychology and Psychiatry, studied 79 new mothers and their babies, who were an average age of 7 months.

For the study, mothers in their own homes were asked to pick up their babies and cradle them in their arms. The mothers also completed a survey that quizzed them on their mental states.

The study found that of the majority of mothers who expressed no signs of stress or depression in the survey (86 percent) preferred to hold their babies to the left; however, cradling babies to the right was more prominent among stressed moms with 32 percent showing a right-sided bias.

The findings are important, the researchers said, because one in 10 mothers develops post-partum depression and most new mothers often don't realize they are stressed.

Studying non-verbal cues such as baby cradling potentially could help doctors and health visitors identify which mothers are in need of extra professional support before it gets too late, researchers said.

"These sorts of feelings can have a huge impact on the relationship between mother and baby and on the family as a whole," said lead author, Dr. Nadja Reissland, a senior lecturer with Durham University’s Department of Psychology. "If this stress develops into depression, then the situation can be even worse."

The research team was following up this pilot study with another that looks at cradling side in a before-and-after situation with mothers taking their babies for their first vaccinations.