ScienceDaily (Feb. 22, 2010) — Women who gain excessive weight during
pregnancy, especially in the first trimester, may increase their risk of
developing diabetes later in their pregnancy, according to a study by the
Kaiser Permanente Division of Research that appears online in the current
issue of Obstetrics and Gynecology.
The three-year study of 1,145 pregnant women from an ethnically diverse
population found that women who gained more weight than is recommended by
the Institute of Medicine had a 50 percent increased risk of developing
gestational diabetes mellitus, also known as GDM. The association between
pregnancy weight gain and gestational diabetes risk was more pronounced
among overweight and non-white women. The study included 345 pregnant women
with gestational diabetes and 800 pregnant women without gestational
diabetes.
Gestational diabetes is defined as glucose intolerance that typically occurs
during the second or third trimester of pregnancy. It causes complications
in as much as seven percent of pregnancies in the United States. It can lead
to early delivery, C-sections and type 2 diabetes, and can increase the
child's risk of developing diabetes and obesity later in life.
This study is among the first to support a direct link between pregnancy
weight gain and gestational diabetes risk. Previous research has shown that
weight gain before pregnancy and being overweight or obese at the start of
pregnancy are risk factors for gestational diabetes. This study was funded
by the American Diabetes Association and the National Institute of Diabetes
and Digestive and Kidney Diseases.
The study followed women members of Kaiser Permanente Northern California
region and examined their overall rate of pregnancy weight gain up to the
time of screening for gestational diabetes (typically between 24-28
gestational weeks), as well as the trimester-specific rates of weight gain
compared to the Institute of Medicine's 2009 guidelines for recommended
pregnancy weight gain. Based on a woman's pre-pregnancy body mass index, the
IOM developed the 2009 guidelines for obstetricians to counsel pregnant
women on suggested weight gain during pregnancy.
After adjusting for age at delivery, race/ethnicity, previous births, and
pre-pregnancy body mass index, the risk of gestational diabetes increased
with increasing rates of pregnancy weight gain. Women who exceeded the IOM
guidelines for weight gain had a 50 percent increase in the risk of
gestational diabetes compared to women who gained within or below the IOM
recommendations.
"Health care providers should talk to their patients early in their
pregnancy about the appropriate gestational weight gain, especially during
the first trimester, and help women monitor their weight gain. Our research
shows that weight gain in early pregnancy is a modifiable risk factor for
gestational diabetes," said the study's lead author Monique Hedderson, PhD,
a scientist at the Kaiser Permanente Division of Research. "Randomized
studies are needed to determine the feasibility of this early intervention
and the best methods to help women meet the IOM recommendations."
Though the exact mechanism for how excessive weight gain may contribute to
gestational diabetes is not known, researchers hypothesize that rapid weight
gain early in pregnancy may result in an early increase in insulin
resistance that leads to the "exhaustion" of the beta-cells in the pancreas
that make and release insulin, which controls the level of glucose in the
blood. This could reduce beta-cells' capacity to secrete adequate levels of
insulin to compensate for the insulin resistance induced by the progression
of pregnancy and therefore lead to the development of gestational diabetes,
researchers said.
A strength of the study is its representative and ethnically diverse
population. However, some limitations should be considered. Pre-pregnancy
weights were self-reported for most women. However, researchers have no
reason to believe that the women who developed gestational diabetes would
have misreported their pre-pregnancy weight more than control women and
results were similar when looking at the sub-group of women who had a
measured pre-pregnancy weight.
This study is part of ongoing research at Kaiser Permanente to understand,
prevent and treat gestational diabetes. A recent published Kaiser Permanente
study of 16,000 women in Hawaii found that more than 10 percent of women of
Chinese and Korean heritage may be at risk for developing gestational
diabetes. Another published Kaiser Permanente study of 10,000 mother-child
pairs showed that treating gestational diabetes during pregnancy can break
the link between gestational diabetes and childhood obesity. That study
showed, for the first time, that by treating women with gestational
diabetes, the child's risk of becoming obese years later is significantly
reduced.
The study follows other research at Kaiser Permanente regarding healthy
weight gain during pregnancy. A recent published Kaiser Permanente study
found that obese women who gain more than the recommended amount during
pregnancy are much more likely to retain a portion of that weight one year
after they give birth. Another published Kaiser Permanente study of 40,000
mother and baby pairs found that women who gained more than 40 pounds during
their pregnancies were nearly twice as likely to have a heavy baby.
Assiamira Ferrara, MD, PhD, a research scientist with the Kaiser Permanente
Division of Research in Oakland, Calif., is the senior investigator on this
study. Erica P. Gunderson, PhD, also with the Kaiser Permanente Division of
Research, is an investigator on this study.
Source : ScienceDaily LLC
