- The HbA1c test (also called the A1c test) conducted as early as the 10th week of pregnancy may help identify women at risk for gestational diabetes, early enough for lifestyle changes to be effective, according to research from the National Institutes of Health.
- NIH researchers analyzed records from the National Institute of Child Health and Human Development's NICHD Fetal Growth Study of more than 2,000 low-risk pregnant women from 12 U.S. clinical sites between 2009 and 2013.
- They compared HbA1c test results from 107 women who later developed gestational diabetes to test results from 214 women who did not. Each 0.1 percent increase in HbA1c above 5.1 percent in early pregnancy was associated with a 22 percent higher risk for gestational diabetes, the research found.
Most women with gestational diabetes deliver healthy babies. However, if not carefully managed, gestational diabetes can lead to pregnancy complications such as high blood pressure or increase the mother’s chance of needing a cesarean delivery. For infants, gestational diabetes raises the risk for large birth size.
The HbA1c test, the gold standard for diabetes screening, is not currently recommended to diagnose gestational diabetes at any point in pregnancy. The test measures the percentage of sugar attached to the hemoglobin in red blood cells.
Women typically are screened for gestational diabetes only if they have a known risk factor, such as obesity. Then, screening usually occurs between 24 and 28 weeks of pregnancy, using a glucose challenge test or oral glucose tolerance test.
With a glucose challenge test, blood is drawn one hour after the patient drinks a sweet liquid. The oral glucose tolerance test involves measuring blood glucose after a fast of at least eight hours.
Exercise and a healthy diet may lower blood glucose levels during pregnancy, or physicians may prescribe insulin to bring blood glucose under control.
“Our results suggest that the HbA1c test potentially could help identify women at risk for gestational diabetes early in pregnancy, when lifestyle changes may be more effective in reducing their risk,” according to study author Cuilin Zhang of the epidemiology branch at NIH’s NICHD.
The study appears in Scientific Reports.