AT THE PREGNANCY MEETING
SAN DIEGO (FRONTLINE MEDICAL NEWS) – Maternal glycemia was associated with anthropometric measures of obesity in offspring during childhood, but not with childhood body mass index, fasting glucose, or insulin resistance in a secondary analysis of a long-term follow-up study of women with mild gestational diabetes mellitus.
Baseline maternal body mass index (BMI), maternal weight gain, and Hispanic ethnicity, however, were consistently related to childhood BMI (P < .01) in the study of 236 children born to women who had untreated mild gestational diabetes mellitus (GDM) and 480 children whose mothers had a normal oral glucose tolerance test during pregnancy.
The findings underscore the importance of reducing obesity prior to pregnancy, and suggest that obesity reduction efforts should be emphasized in clinical practice, Dr. Mark B. Landon said at the annual Pregnancy Meeting sponsored by the Society for Maternal-Fetal Medicine.
“The obesity epidemic certainly has not spared the pediatric population,” said Dr. Landon, chair of obstetrics and gynecology at the Ohio State University in Columbus.
And a serious concern is that overweight and obesity are associated with a downstream risk of both metabolic and cardiovascular abnormalities into adulthood, he added.
Hispanic ethnicity and maternal BMI were also associated with childhood homeostatic model assessment-insulin resistance (HOMA-IR), and Hispanic ethnicity was associated with fasting glucose, Dr. Landon reported on behalf of the National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network.
There was a significant correlation between fasting, 1-hour, 2-hour, and 3-hour maternal glucose and subscapular/triceps skin fold ratio (Spearman correlation coefficients, 0.10, 0.08, 0.11, and 0.12, respectively). Similar correlations were seen between maternal glucose and HOMA-IR, and maternal glucose and sum of skin folds.
Fasting maternal glucose and fasting child glucose were also significantly correlated (Spearman correlation coefficients, 0.09).
On multivariable regression analysis – after controlling for maternal and neonatal factors – the only significant correlations between maternal glycemia and childhood outcomes were for 1-hour, 2-hour, and 3-hour maternal glucose measures, sum of skin folds, and subscapular/triceps skin fold ratio, he said.
Study subjects were the offspring of women who underwent a 3-hour oral glucose tolerance test between 27 and 31 weeks’ gestation, and childhood outcomes were assessed between the ages of 5 and 10 years.
Prior to the widespread recognition of the concept of fetal programming over 3 decades ago, Dr. Norbert Freinkel proposed that mild forms of diabetes, such as GDM, might exaggerate the normal dependency of the fetus on maternal fuels and that the concept of teratogenesis should be expanded to include alterations which could have long-range effects on behavioral, anthropometric, and metabolic functions, Dr. Landon said.
Multiple subsequent studies have demonstrated a link between in utero exposure to maternal hyperglycemia and the development of obesity in childhood – findings that are independent of both birth weight and maternal obesity.
A 2013 study showed that GDM was associated with both overweight status in childhood and childhood obesity ( Diabet. Med. 2013;30:1449-56 ). Also, the landmark Hyperglycemia and Adverse Pregnancy Outcomes study showed that with increasing maternal glucose levels lower than the threshold for GDM diagnosis, the frequency of large-for-gestational-age infants increased proportionately – and this risk also remained after adjustment for maternal BMI and other confounders ( N. Engl. J. Med. 2008;358:1991-2002 ).
“We have similarly reported a monotonic relationship between maternal glucose levels and the frequency of large-for-gestational-age infants in a secondary analysis from the Mild GDM Network randomized controlled trial. Recognizing that maternal glycemia clearly contributes to fetal growth, we sought to determine in this analysis whether the degree of maternal glucose tolerance during pregnancy affects the risk of childhood obesity and metabolic dysfunction,” Dr. Landon said.
Although the findings do not address the potential long-term effects of more significant hyperglycemia during pregnancy, they do confirm that maternal obesity has a greater impact on childhood obesity risk than exposure to mild hyperglycemia during pregnancy, he said in an interview.
Dr. Landon reported having no financial disclosures.