Study Links Mothers’ Weight and Blood-Sugar Levels to Health of Newborns

Pregnant women with weight and blood-sugar levels even slightly above average may pose a risk to their pregnancies and the health of their newborns, a study suggests.

The 2008 Hyperglycemia and Adverse Pregnancy Outcome study showed a possible link between mothers with elevated blood sugar — but below the level of gestational diabetes — and increased birth weight and elevated insulin in newborns.

The new review of data from the HAPO study shows that blood-sugar levels and weight even just above average can boost newborns’ birth weights and insulin levels, and lower blood sugar. Having a larger-than-average baby can lead to infant injuries during delivery and more, risky Caesarean births.

“My recommendation would be that every pregnant mother should have a chance to have dietary advice. It would pay off in the long run,” says Dr. Boyd Metzger, the principle investigator of the study and a professor of medicine-endocrinology at Northwestern University Feinberg School of Medicine. However, many insurance plans don’t cover prenatal dietician visits, he says.

Women who are slightly overweight with moderately elevated blood-sugar levels pose a higher risk than pregnant women who are obese with normal blood sugar, or those who have gestational diabetes (when blood-sugar levels rise to a certain point) and a normal weight, the study says. It included 23,316 women from nine countries and was published in April’s Diabetes Care.

Babies born to mothers that are both obese and have gestational diabetes weigh an average of 340 grams, or about three-quarters of a pound, more than those born to mothers with normal weight and blood sugar, according to the study.

Mothers who are overweight — but not obese — with above-normal blood sugar had babies weighing an average of 214 grams, or half a pound, more. Babies of mothers of normal weight who have gestational diabetes weigh an average of 164 grams — just under a third of a pound — more. And obese mothers with normal glucose level have babies that weigh an average of 174 grams more.

Earlier studies have linked gestational diabetes and other ailments in mothers to health problems later on in the lives of their children, as WSJ reported last year.

There is a potential link between mothers with higher blood-sugar levels and weight, and obesity and diabetes in the children, perhaps as early as childhood, Metzger tells the Health Blog.  But “the unsettled question is whether these milder levels of higher glucose or weight [in the mother] carry that risk,” says Metzger.