A useful mantra for pregnant women is “your baby is what you eat”. And a new study brings this home, led by ­researchers at the University of Oxford, in collaboration with the University of California, Berkeley, US.

They’ve shown, as early as the fifth month of pregnancy, that a mother’s fat metabolism (proxy for what she eats) affects foetal growth and then tracks newborn growth, adiposity and development into childhood.

The study followed 3,500 babies and their mothers, in six countries, from early pregnancy to childhood, and showed early on that the mother’s blood fat levels influenced the growth of the unborn baby.

Furthermore, this influences a child’s weight and its own body fat at two years of age and presumably into adult life. Could this be a way to ­identify infants at risk of being obese – a pressing global health issue?

The researchers monitored the growth inside the womb of over 3,500 babies in six countries (Brazil, Kenya, Pakistan, South Africa, Thailand and the United Kingdom) using ultrasound scans throughout pregnancy, and analysed blood samples taken from the women early in pregnancy and from the baby’s umbilical cord at birth.

They then monitored the growth and development of the infants until two years of age. José Villar, professor of perinatal medicine at the University of Oxford, who co-led the study, said: “This is the first ­comprehensive evidence, across geographic ­populations, of the complex interaction between maternal and foetal metabolism that regulates, early in pregnancy, unique foetal trajectories linked specifically to weight, adiposity and development during childhood.”

Aris Papageorghiou, professor of foetal medicine also at the University of Oxford, another co-leader of the study, commented: “Much has been said about the importance of the first 1,000 days of life in determining future health outcomes.

“The finding of an association with maternal lipid metabolism early in pregnancy also provides unique insights into how the mother’s health and diet influence her child’s adiposity.”

A third co-leader at Oxford, Stephen Kennedy, professor of reproductive medicine, added: “This landmark study has provided valuable new insights into the biological origins of childhood obesity, which is one of the most pressing public health issues facing governments around the world.

“The findings could contribute to earlier identification of infants at risk of obesity.

“Policymakers must take notice of these findings in their efforts to prevent the oncoming epidemic of obesity with all its likely adverse social and economic consequences.”