according to data from a before-and-after cohort study of women in the state of Washington.
The one-step test, a 75-g 2-hour oral glucose tolerance test (OGTT), was recommended for all pregnant women in 2010, although the traditional two-step test – a 50-g screening glucose challenge test followed by a 100-g 3-hour OGTT – remains widely used, wrote Gaia Pocobelli, PhD, of Kaiser Permanente Washington Health Research Institute, Seattle, and her colleagues. “No randomized trial has been published comparing outcomes of the two approaches.”
In a study published in, the researchers compared data from 23,257 women who received prenatal care in Washington State between January 2009 and December 2014, including 8,363 women who received care before the guideline change, 4,103 who received care during a transition period, and 10,791 after the guideline change. Approximately 60% of the women received care from clinicians internal to Kaiser Permanente; 40% received care from external providers. Most (87%) of the internal clinicians switched to the one-step approach, the researchers said. Only 5% of external providers did so.
Overall, adopting the one-step approach was associated with a 41% increase in the diagnosis of GDM without improved maternal or neonatal outcomes, the researchers noted.
The incidence of GDM increased from 7% before the guideline change to 11% afterward for women seen by internal providers. For women seen by external providers, gestational diabetes incidence increased from 10% to 11%.
For women seen by internal providers, the use of insulin increased from 1% before the guideline change to 4% afterward; for women seen by external providers, use of insulin increased from 1.3% to 1.4% (change between the groups P less than .001).
In addition, women seen by internal providers were more likely to undergo induction of labor after the guideline change (25% to 29%), while labor induction decreased for women seen by external providers (31% to 29%) for a relative risk of 1.2.
Neonatal hypoglycemia increased from 1% to 2% among women seen by internal providers, but decreased slightly from 2.4% to 2.1% for women seen by external providers, for a relative risk of 1.77.
There were no significant differences between the women seen by internal and external providers in risk of primary cesarean section, large for gestational age, small for gestational age, or neonatal ICU admission.
The main limitation of the study was the potential confounding variables including maternal diet and exercise, and possible underreporting of risk factors such as smoking, the researchers noted. However, the results were strengthened by the large study population, and the results “do not suggest a benefit of adopting the one-step over the two-step approach.
“Kaiser Permanente Washington has revised [its] guidelines to return to a two-step process. We recommend that any health care system considering switching to the one-step approach incorporate a rigorous evaluation of changes in maternal and neonatal outcomes,” Dr. Pocobelli and her associates added.
Dr. Pocobelli disclosed funding from Jazz Pharmaceuticals for work unrelated to this study. The study was supported in part by a grant from the Group Health Foundation Momentum Fund.