News & Research

By: Felicia Breedy

Boyd E. Metzger, MD, from the Northwestern University Feinberg School of Medicine, Endocrinology, is the lead author of “Hyperglycemia and Adverse Pregnancy Outcomes, The HAPO Study Cooperative Research Group.”

Partially funded by an ADA Federal Co-Support Award, the HAPO study examined whether complications in pregnancy can be associated with lower levels of hyperglycemia than the standards currently used to diagnose gestational diabetes. In a multi-center study, about 25,500 pregnant women underwent the standard oral glucose tolerance testing between 24 and 32 weeks to determine their levels of blood glucose. Those whose levels were high enough to meet the standards for diabetes were excluded from the study. Additional data included height, weight, and blood pressure as well as demographic information relating to the women’s risk factors for diabetes.

Results showed that even those women who were below diagnosing standards for diabetes but still showed higher levels of glucose had significantly higher risks of problems, including: high levels of insulin in the cord blood at delivery; large birth weight for gestational age; birth injuries; hypoglycemia; or low blood sugar in the newborn period. Clarifying the level at which treatment should begin for gestational diabetes to avoid these problems is still unknown. Dr. Metzger states, “There were no obvious thresholds at which risks increased.” The findings were published in the May 8 issue of The New England Journal of Medicine.

With funding from the ADA, Dr. Metzger and the HAPO study were also able to collect blood for DNA testing from the mothers and babies and, additionally, perform measurements of C- peptide levels in the mothers during their oral glucose tolerance test. These are being used as an index of maternal insulin resistance and of insulin secretion. The HAPO Genetics Study Group has also received two NIH grants that will allow them to study factors related to maternal glycemia and fetal growth.