From the Journals

One-step gestational diabetes screening doesn’t improve outcomes

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Current data don’t support change in screening protocol

Diabetes is a significant global public health concern, but is especially problematic for women of reproductive age because diabetes in pregnancy can cause significant health complications for the mother and baby. Gestational diabetes mellitus (GDM) affects up to 10% of pregnancies in the United States annually, and is associated with perinatal loss, operative delivery, macrosomia, hypoglycemia, respiratory distress syndrome, and metabolic derangements for the offspring. For the mother, GDM is associated with hypertensive disorders, infections, hydramnios, and increased risk for developing type 2 diabetes later in life. As the incidence of GDM continues to rise, studies examining how to reduce, manage or prevent this condition become increasingly important.

The authors’ conclusions, that adopting the one-step approach increased the number of women with diagnosed GDM but did not significantly improve maternal or neonatal outcomes, are not surprising. Since the initial publication of the Hyperglycemia and Adverse Pregnancy Outcome Study, upon which the International Association of the Diabetes in Pregnancy Study Groups based its recommendations to go to a one-step approach, much debate has ensued about the best method to diagnose GDM. Indeed, the National Institutes of Health convened a consensus panel to review the literature and determine whether the one-step approach should be universally adopted (the panel concluded that more information was needed, and that the current two-step approach should continue to be used).

As the authors concede, studies have shown conflicting results, and no large-scale randomized controlled trial has been conducted to date. However, the literature does not bear out the idea that the one-step approach is truly better. The current study, although including a significant number of women and a reasonable control group, only serves as yet another study to reinforce what has previously been published.

I would agree with the researchers’ conclusions that the one-step approach is not necessarily beneficial. Although the one-step approach may identify a subset of patients who might not otherwise be diagnosed with GDM, it still remains unclear whether the outcomes for these patients will be improved. Furthermore, additional testing, need for insulin or other oral antidiabetic medications, etc., would result in additional stress to the patient and the health care system. Based on the authors’ findings, and results of other studies, it remains to be determined if the effort (diagnosing additional patients with GDM) is justified medically, economically, or otherwise.

As ob.gyns., we must continually ask ourselves: “By not doing something, are we causing harm to our patients?” If we change the diagnostic criteria for GDM, thereby increasing the number of women with the condition who would then require additional care, medications, and, potentially, more complex decisions around timing and mode of delivery, we need to be certain that we are not doing harm. This, and other studies examining the use of the one- versus two-step approach have yet to demonstrate, unequivocally, that changing the criteria reduces harm, and, perhaps, might – unintentionally – cause more.

As the study authors and the NIH consensus panel concluded, more rigorous evaluation is needed; that is, a large, multicenter randomized controlled trial that examines not only the benefits during pregnancy but also the long-term benefits to women and their children.

Dr. E. Albert Reece, vice president for medical affairs at the University of Maryland, Baltimore, and the John Z. and Akiko K. Bowers Distinguished Professor and dean of the school of medicine.

Dr. E. Albert Reece

E. Albert Reece, MD, PhD, MBA, who specializes in maternal-fetal medicine, is vice president for medical affairs at the University of Maryland, Baltimore, as well as the John Z. and Akiko K. Bowers Distinguished Professor and dean of the school of medicine. He provided commentary on the study by Pocobelli et al. Dr. Reece said he had no relevant financial disclosures.



A one-step protocol for gestational diabetes screening increased diagnoses by 41% with no evidence of improvement in maternal or neonatal outcomes, 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 Obstetrics & Gynecology, 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.

SOURCE: Pocobelli G et al. Obstet Gynecol. 2018;132:859-67.

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