New York, Nov 15 (IANS): A woman's stress levels during pregnancy can cause changes in the microbiome of the foetus that can lead to anxiety as well as learning difficulty in babies, persisting even into adulthood, researchers say.

In the study, the team of researchers at The Ohio State University, found that when pregnant mice were exposed to stress, it appeared to change the makeup of the bacteria in both their guts and placentas, as well as in the intestinal tracts of their female offspring.

Markers of inflammation increased in the placenta, the foetal brain and the adult brain of the offspring while a supportive protein called brain-derived neurotrophic factor (BDNF) decreased. And these microbial changes lasted into adulthood.

The mice were more anxious, they spent more time in dark, closed spaces and they had a harder time learning cognitive tasks even though they were never stressed after birth, the researchers said.

Further, the female offspring of the stressed mice showed a lower ability to learn and higher anxiety-like behaviour compared to the offspring of non-stressed mother mice.

"Microbes from a mother's gastrointestinal and reproductive tracts are the first to colonise in a developing foetus and newborns," said led researcher Tamar Gur, Assistant Professor at Ohio State.

"That makes the bacteria an interesting potential explanation of why and how stress before an animal or person is born could prompt mental illness that can last a lifetime," Gur added.

The study was presented at Neuroscience 2016, the annual meeting of the Society for Neuroscience in San Diego, recently.