Fatter Women Have Fatter Babies

What did the Imperial College study find?

Newborn babies tend to carry more body fat — including fat in the liver — when their mothers had a higher body mass index (BMI) before becoming pregnant, according to research from Imperial College London published in Pediatric Research in 2011.

The team, led by Professor Neena Modi, a consultant neonatologist at Chelsea and Westminster Hospital, used MRI scanning to assess 105 babies born at the hospital. The sleeping infants were scanned to measure total body fat, its distribution, and the fat content of liver cells. The result: liver fat and total fat — particularly around the abdomen — increased across the entire range of maternal BMI, not just at the obese end.

Why does it matter?

"This study demonstrates that a woman's BMI, even in the normal range, affects the amount of fat in her baby at birth," Modi said. "Fatter women have fatter babies and there is more fat in the babies' livers. If these effects persist through childhood and beyond, they could put the child at risk of lifelong metabolic health problems."

Children of overweight and obese mothers are already known to face higher odds of becoming overweight themselves and of developing conditions like type 2 diabetes. The researchers suggested the fat patterns they found might be the first biological changes — which, combined with an unhealthy lifestyle later, could set the child on a path to poorer health.

What should mothers do?

Modi's conclusion was blunt: "There is growing evidence that a baby's development before birth has a major impact on their health in later life. This means that the prevention of obesity needs to begin in the womb." The team argued for identifying the optimal pre-pregnancy BMI so women could be helped to reach their best condition before conceiving — a shift from treating obesity as an adult problem to treating it as a generational one.