ACOG Stands By 2-Step Gestational Diabetes Screening Approach

Nancy A. Melville

August 24, 2011

August 24, 2011 — The American College of Obstetricians (ACOG) is standing by its recommendation for a 2-step approach to screening and diagnosis for gestational diabetes mellitus (GDM) in the continued absence of an international consensus on whether the benefits of some screening approaches outweigh the costs, according to a committee opinion published in the September issue of Obstetrics & Gynecology.

GDM is associated with risks to the fetus and newborn, including shoulder dystocia, birth injuries, and hyperbilirubi¬nemia, and it has also been shown to pose maternal risks, including preeclampsia, caesarean delivery, and an increased risk of developing type 2 diabetes later in life.

ACOG reports that GDM, which already complicates about 7% of all pregnancies in the United States, is on the rise, likely because of increasing rates of obesity and overweight.

In 2001, the group recommended a "2-step" approach for screening and diagnosing for the disease, and ACOG's Committee on Obstetric Practice reiterated its guidelines this week, adding a third recommendation against an alternative approach outlined by the International Association of Diabetes in Pregnancy Study Group.

The recommendations are as follows:

  1. "All pregnant women should be screened for GDM by patient history, clinical risk factors, or a 50-g, 1-hour loading test to determine blood glucose levels."

  2. "The diagnosis of GDM can be made based on the result of the 100-g, 3-hour oral glucose tolerance test, for which there is evidence that treatment improves outcome. Either the plasma or serum glucose level established by Carpenter and Coustan or the plasma level designated by the National Diabetes Data Group is appropriate to use. A posi¬tive diagnosis requires that 2 or more thresholds be met or exceeded."

  3. "Diagnosis of GDM based on the 1-step screen¬ing and diagnosis test outlined in the International Association of Diabetes in Pregnancy Study Group guidelines is not recommended at this time because there is no evidence that diagnosis using these cri¬teria leads to clinically significant improvements in maternal or newborn outcomes, and it would lead to a significant increase in healthcare costs."

Debate over GDM recommendations increased in 2008 when the US Preventive Services Task Force concluded that there was insufficient evidence to balance the benefits and harms of screening for GDM, according to the committee opinion.

The same year, the International Association of Diabetes in Pregnancy Study Group issued recommendations for the diagnosis and classification of hyperglycemia during pregnancy based on research published by the Hyperglycemia and Adverse Pregnancy Outcomes Study Cooperative Research Group.

That study demonstrated a "clear and continuous rela¬tionship between maternal hyperglycemia and increas¬ing rates of large for gestational age infants, cord blood C-peptide (evidence of fetal hyperinsulinemia), neonatal hypoglycemia, and caesarean delivery," according to the ACOG committee report.

The study group's guidelines recommended that, in addition to recommendations concerning the identifica¬tion of overt diabetes during pregnancy, a simplified "1-step" approach should be taken for the screening and diagnosis of GDM with a 75-g, 2-hour glu¬cose tolerance test.

However, in departing from ACOG's recommended 2-step screening approach, the study group's guidelines indicate that "a universal recommendation for the ideal approach for screening and diagnosis of GDM remains elusive," according to the ACOG committee opinion.

"Significant questions remain regarding the implications on health care costs, the effect of GDM diagnosis on the pregnant woman and her family, the effect of diagnosis on obstetric interventions in pregnancy, and whether the identification and treatment of GDM will improve meaningful perinatal, neonatal, and maternal outcomes," the committee added.

In an effort to bring groups together to establish more uniform screening and diagnostic criteria, the National Institutes of Health is planning a consensus development, and the ACOG committee underscored the importance of a productive outcome from the effort.

"Consensus regarding optimal diagnostic criteria among the many groups and professional organizations will further much-needed research regarding the benefits and harms of screening and diagnosis of GDM," the ACOG committee noted.

Obstet Gynecol. 2011;118:751-753. Full text


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