A child's risk of obesity as they grow up can be influenced by modifications to their DNA while in the womb caused by their mother's "health, diet and lifestyle", according to new research.
Scientists at the University of Southampton have found that the changes which occur prior to birth can have a long-term impact on the child's health.
The researchers examined umbilical cord tissue of babies born in a study based in the Hampshire city to examine these epigenetic modifications which control the activity of our genes without changing the actual DNA sequence.
One of the main epigenetic modifications is DNA methylation, which plays a key role in embryonic development and the formation of different cell types, regulating when and where genes are switched on.
The researchers say that there is growing evidence that the level of DNA methylation can be affected by a range of environmental factors such as parental health, diet and lifestyle.
Lead author Karen Lillycrop said the study results could help develop strategies to prevent obesity as a child grows up.
She said: "This is exciting new evidence that epigenetic changes detectable at birth are linked to a child's health as they grow up.
"It was very promising to see our initial findings confirmed in so many other cohorts. Not only does it strengthen the body of evidence that shows a mother's health during pregnancy can affect the future health of her child, but it could also allow us to more accurately predict the future risk of obesity.
"If we can do this, then strategies can be developed in early life to prevent the development of obesity."
Professor Keith Godfrey, from the Medical Research Council Lifecourse Epidemiology Unit and the National Institute for Health Research Southampton Biomedical Research Centre, said: "The new findings provide the first direct evidence linking faltering of a baby's growth in the womb with epigenetic modifications that themselves may increase the risk of childhood obesity.
"The findings are now helping us to trial new nutritional interventions before and during pregnancy to reduce the baby's risk of obesity in childhood and later life, and strengthen the view that effective prevention of childhood obesity has to begin before the baby is born.
"The findings may also lead to innovative approaches to the treatment of established obesity in later life."
:: The study, carried out by the EpiGen Global Consortium, is published in EBio Medicine.
Dr Panagiota Mitrou, director of research funding at World Cancer Research Fund, said: "This fascinating study emphasises the need to live a healthy lifestyle at all life stages - particularly before conception and during pregnancy.
"It is incredibly important that expectant mothers make healthy lifestyle choices to prevent childhood obesity, which can put the child at risk of many serious health conditions, including 11 common cancers, in later life.
"After not smoking, maintaining a healthy weight is the most important thing individuals can do to reduce their cancer risk."