There's a reason much of the research in fetal programming has been done in rats -- giving pregnant women medication of any kind is a touchy topic. This is why the U.K. trial has met with some controversy, as doctors will be dosing mothers with drugs that they don't strictly need.
But the trial may not be as far a leap into the unknown as it seems, doctors point out:
"Metformin is not a new drug and has been given to pregnant women for years to control diabetes in pregnancy," says Dr. Alan Peaceman, chief of the division of maternal fetal medicine at Northwestern Memorial Hospital.
While diet and exercise would be the preferred intervention for obese mothers, "patients often find this difficult, especially during pregnancy. Thus, Metformin may provide an alternative option for these women with similar lifelong benefits to the fetus," adds Dr. Victoria Bae-Jump, assistant professor of gynecology oncology at UNC-Chapel Hill.
Doctors seem more concerned that this type of fetal programming intervention can only provide a partial answer to the problem of maternal obesity.
"Ultimately, it's unlikely that a single pill or nutrient is going to override all the effects of maternal obesity on infant development," says Stuebe. There are so many environmental factors in play -- poverty, abuse, stressful environments, she says, that "I'm skeptical of a magic pill to counteract all that."