A CHILD’S risk of obesity and diabetes might be pre-programmed in the womb before it is even born, German scientists have found.
The study is the first direct evidence that the foetal brain response to a dose of sugar given to its mother is associated with the mother’s insulin sensitivity.
This may indicate that the risk of subsequent obesity and diabetes may be pre-programmed in the womb.
Children of obese and diabetic mothers already have an increased risk for type 2 diabetes and obesity in adulthood, independent of their genetic background, and the rate in the general population is rising.
The reason is unclear, although environmental and genetic mechanisms are likely to be involved.
A major genetic mechanism is the so-called foetal programming system, whereby the mother’s exposure to environmental factors can affect programming of the genes in her unborn child.
Scientists aimed to show that the metabolism of a pregnant woman, following a meal, influences foetal brain activity.
A total of 13 healthy pregnant women underwent an oral glucose tolerance test. Insulin sensitivity was determined by glucose and insulin measurements at 0, 60 and 120 minutes.
At each time point, the response of the foetus was examined by recording foetal brain responses to sounds.
The researchers found that after 60 minutes, women who were more insulin-resistant had foetuses that reacted more slowly to the sound test.
When divided into two groups based on insulin sensitivity, the insulin-resistant mothers had foetuses that reacted to the sound at an average of 283 milliseconds, compared with 178 ms for the insulin-sensitive group.
Research author Dr Hubert Preissl, from the University of Tübingen, said: “It is possible that insulin-resistant mothers have higher glucose levels accompanied by increased insulin levels after a meal.
“As glucose passes the placenta, these increased glucose levels induce excess insulin in the foetus. So high insulin levels in the mother may correspond to high insulin levels in the foetus.”
The study, published in Diabetologia, also discusses other possible reasons for the difference in audio response times, which could be the insulin resistance of the mother creating the same effect for a different reason.
Dr Preissl added: “Insulin resistance of the foetal brain may have important consequences for later life. Compared with newborns of non-diabetic women, children of diabetic mothers with poorly controlled glycaemia show neurophysiological impairment and have a higher risk of obesity and type 2 diabetes.”
“Lower maternal insulin sensitivity is associated with slower foetal brain responses. These findings provide evidence of a direct effect of maternal metabolism on foetal brain activity and suggest that central insulin resistance may be programmed during foetal development.”