June 22, 2007 (Chicago) -- Blood sugar levels previously thought normal for pregnant women may signal problems for their babies, an international study shows.
Doctors already know that gestational diabetes in a mother can mean big problems for her newborn baby. Some 4% of pregnant women develop this condition, in which women who didn't have diabetes previously have their blood sugar levels soar. It usually goes away after pregnancy but has a two-in-three chance of retuning in subsequent pregnancies.
Babies born to women with gestational diabetes have to struggle with too much sugar crossing the placenta into their blood. The extra energy makes them grow to a large size -- often forcing a C-section to prevent birth injury.
And all the insulin they're forced to produce may give the babies low blood sugar at birth or cause breathing problems at birth. It may even predispose them to develop obesity in childhood and type 2 diabetes later in life.
Now it looks as though these problems occur even in women who don't have frank gestational diabetes, says Boyd E. Metzger, MD, of Northwestern University, Chicago. Metzger chaired a seven-year, international study that tracked 23,325 pregnancies in nine nations. None of these women had gestational diabetes.
"There has been debate about whether adverse pregnancy outcomes are really related to mothers' blood sugar. There has been a holding back on considering this a problem," Metzger said at a news conference. "These data show there are clear relationships between blood sugar and outcome in women who could not be said to have diabetes in the traditional sense."
Metzger tells WebMD that the vast data collected in the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study are still being analyzed. He's confident that the data will lead to a set of international recommendations for maternal blood sugar testing.
Metzger is also confident that medical associations are likely to change their advice to women about what level of blood sugar is considered safe during pregnancy. But he and his colleagues are not yet ready to say what that level might be.
"One of the strong messages to deliver is there is value to pregnant women in having their glucose levels tested and analyzed," he said.
Metzger and colleagues discussed the study in a symposium held at the American Diabetes Association's 67th Annual Scientific Sessions, held June 22-26 in Chicago.