Big Way Of Life

How far will we go to prevent childhood obesity? UK researchers are bringing the battle against obesity to babies still in the womb.

In this novel approach, which will ultimately enlist 400 pregnant women in the UK, obese pregnant women will be given the diabetes drug Metformin in hopes of reducing their infant's chance of developing heart disease, obesity and type 2 diabetes later in life.

The study, funded by the government, will be one of the most extensive tests to date of a concept known as fetal programming -- changing the environment of the womb to affect the health of the child.

Doctors already use "fetal programming" in less extreme ways by encouraging pregnant women to take prenatal supplements, make dietary changes, and avoid drug and alcohol use.

This study promises to introduce a whole new level that might one day be commonplace: using medications that the mother otherwise wouldn't need in order to tweak the fetal environment.

Natural fetal programming "is a complex process that's evolved over millions of years to help a fetus adapt to the world it will ... encounter after birth," says Dr. Alison Stuebe, an assistant professor of maternal fetal medicine at UNC-Chapel Hill.

"It is the way the mother 'tells' her baby what the world outside will be like."

Obese women tend to have higher blood sugar during pregnancy, and these high levels of blood sugar essentially "tell" the fetus that it needs to make a lot of insulin for itself. As a result, infants born to obese mothers tend to be heavier and produce more insulin. Research shows that these bigger babies grow up into children and adults who are at increased risk for obesity, heart disease and type 2 diabetes.

By giving obese mothers-to-be the diabetes drug Metformin -- even though they do not have diabetes -- researchers will be lowering their glucose levels, hopefully mitigating the negative effects of maternal obesity.

It will take years to determine if this intervention pays off. In the short term, however, how big these infants are at birth will serve as a preliminary marker of how well the Metformin is adjusting fetal environment.

Fetal programming was first discussed when U.K. epidemiologist David Barker noted that infants born to malnourished mothers who had lived through the WWII Dutch "hunger winter" had an increased risk of heart disease later in life.

Ironically, research has since confirmed that both overeating and undereating during pregnancy can increase an infant's risk of obesity and heart disease later in life, but for very different reasons.

Instead of having too much blood sugar, babies born to underweight mothers are programmed to believe the world has little food and hence they must retain calories at all costs, says Dr. Hye Heo, a fetal programming expert at Montefiore Medical Center, who's currently working on the effects of feast and famine on infant outcomes in rats.

Heo said: "At this stage in the research, we're still trying to understand what is being altered in the womb, why there is some kind of memory [in the fetus] that persists and results in alterations in the way we develop later on in life."