One-step gestational diabetes screening doesn’t improve outcomes

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

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.