Twice As Many Pregnant Women To Soon
Be Diagnosed With Gestational Diabetes
Two to three times more pregnant women may soon be diagnosed
and treated for gestational diabetes, based on new measurements
for determining risky blood sugar levels for the mother and her
unborn baby, according to a study that was coordinated by investigators
at Northwestern University Feinberg School of Medicine.
"As result of this study, more than 16 percent of the entire
population of pregnant women qualified as having gestational diabetes,"
said lead author Boyd Metzger, M.D., the Tom D. Spies Professor
of Metabolism and Nutrition at Feinberg and a physician at Northwestern
Memorial Hospital. "Before, between 5 to 8 percent of pregnant
women were diagnosed with this."
Blood sugar levels that were once considered in the normal range
are now seen as causing a sharp increase in the occurrence of
overweight babies with high insulin levels, early deliveries,
cesarean section deliveries and potentially life-threatening preeclampsia,
a condition in which the mother has high blood pressure that affects
her and the baby.
Large babies, the result of fat accumulation, are defined as
weighing in the upper 10 percent of babies in a particular ethnic
group. Because large babies increase the risk of injury during
vaginal delivery, many of the women in the study were more likely
to have a cesarean section.
Previous guidelines to diagnose gestational diabetes were based
on blood sugar levels that identified women at high risk for developing
diabetes in the future. The guidelines weren't related to risks
to the baby or other risks to the mother.
The study will be published in the March issue of Diabetes Care,
a journal of the American Diabetes Association.
The good news, Metzger noted, is recent studies show women with
mild gestational diabetes, who were treated with lifestyle and
diet changes as well as blood sugar monitoring, greatly reduced
their risk of complications. As a result of treatment, the women
had smaller babies, fewer cesarean deliveries and less preeclampsia,
Based on a study of more than 23,000 women in nine countries,
Metzger and an international group of 50 experts concluded a fasting
blood sugar level of 92 or higher, a one-hour level of 180 or
higher on a glucose tolerance test or a two-hour level of 153
or higher on a glucose tolerance test constitute serious risks
to the mother and baby. Previously, these levels had been considered
in the safe, normal range, and two elevated levels were required
for a diagnosis of gestational diabetes.
"At these levels, the frequency of having an overweight
baby is almost double, the frequency of having preeclampsia is
almost double, and the frequency of early delivery is 40 percent
greater," Metzger said. "These are really substantial
The group of international experts in gestational diabetes spent
almost two years determining how to apply findings from a 2008
study, also led by Metzger, that found a much lower level of a
pregnant woman's blood sugar than previously believed increased
the risk of serious complications.
The researchers set their new diagnosis and treatment criteria
by determining the blood sugar level that nearly doubled the risks
to the baby and mother.
"This study says these risks to pregnancy are like many
things we deal with in medicine," Metzger said. "The
risk of having a stroke doesn't begin when your blood pressure
is 140 over 80. That's when we say you have hypertension, but
that's not where the risk begins to affect your health. That starts
sooner. A similar situation is how your cholesterol level relates
to the risk of having heart disease. It doesn't begin at 200.
That's where it reaches the threshold where common treatments
can reduce the risks."
"Our research represents an examination of risks and a consensus
about how high a level the risk needs to reach before a diagnosis
should be made and treatment should be considered," Metzger
For the past decade, the rate of gestational diabetes as previously
measured has soared as much as 50 percent. "We shouldn't
be surprised," Metzger said. "The fact that we have
a lot of gestational diabetes to deal with is consistent with
the major impact that diabetes and obesity are having in our population
at large. How could we expect pregnancy to escape that?"
March 1, 2010