Aug. 30 (HealthDay News) -- Can spotting unhealthy levels of stress in a new mother be as simple as seeing which arm she uses to carry her baby?

A new British study suggests that mothers who cradle their baby on their right side may be struggling with extreme stress.

While most new mothers feel some levels of stress during the first weeks and months of their infant's life, the study by Durham University researchers suggests that baby-cradling habits may indicate whether this stress could become increasingly hard to handle and lead to depression. Maternal depression can have a negative effect on a baby's mental and emotional well-being.

And because as many as 10 percent of new mothers develop postpartum depression, identifying warning signs could potentially help health-care providers identify mothers who might be prone to emotional difficulties, the researchers said.

Previous research had shown that the majority of mothers prefer to cradle their baby on their left side, even if they aren't left-handed.

For the new study, published in the August online version of the Journal of Child Psychology and Psychiatry, the researchers included 79 new mothers and babies who were an average age of seven months. The mothers were asked to pick up their babies and cradle them in their arm. They also completed a survey on their mental state.

According to the researchers, 86 percent of mothers who exhibited no signs of stress or depression in the survey preferred to hold their babies to the left. But, 32 percent of mothers showing signs of elevated stress held their babies to the right.

Lead author Dr. Nadja Reissland, a senior lecturer at Durham University's psychology department, said, "Many mothers don't realize they are suffering from stress, or don't want to admit they are. The way they interact with their child is usually the best indicator of their inner mental state."

"Mums who are stressed often see what their baby does as negative, so they may interpret their baby's crying as being naughty, when, in fact, this is normal behavior. They may even feel the baby is stopping them from living the life they really want to live," she added in a prepared statement.

"These sorts of feelings can have a huge impact on the relationship between mother and baby and on the family as a whole. If this stress develops into depression, then the situation can be even worse," Reissland said.

SOURCE: Durham University, United Kingdom, news release, Aug. 28, 2007