New Optimal Screening Threshold for Gestational Diabetes in Twin Pregnancies
Ideal 1-hour 50-g glucose challenge test cutoff ≥135 mg/dL, say researchers
in the American Journal of Obstetrics & Gynecology
Ideal 1-hour 50-g glucose challenge test cutoff ≥135 mg/dL, say researchers in the American Journal of Obstetrics & Gynecology
Philadelphia, PA, October 30, 2014
A common complication, gestational diabetes affects approximately 6-7% of pregnant women. Currently, screening is done in two steps to help identify patients most at risk; however, the suggested levels for additional testing were based on singleton pregnancy data. Now investigators have analyzed data from twin pregnancies and have determined that the optimal first step cutoff for additional screening appears to be a blood sugar level equal to or greater than 135 mg/dL for women carrying twins. Their findings are published in the American Journal of Obstetrics & Gynecology.
Representing approximately 3.3% of all live births in the United States, twin pregnancies present unique medical challenges; however, most of the available data regarding GDM testing thresholds are based on singleton pregnancies. Since carrying twins amplifies the normal physical changes that accompany pregnancy, a team of researchers from the Icahn School of Medicine at Mount Sinai and the New York University School of Medicine set out to pinpoint the most effective screening cutoff for women pregnant with twins.
Currently, the American Congress of Obstetricians and Gynecologists advocates a two-step diagnostic approach. Women are screened between 24-28 weeks, using a nonfasting 1-hour 50-g glucose challenge test (GCT). If a patient exceeds the recommended cutoff (between ≥130 mg/dL and ≥140 mg/dL), additional testing is performed to diagnose or rule out GDM.
In this study, doctors analyzed data from 475 women pregnant with twins who were treated at their hospitals between 2005 and 2013. Specifically, they focused on three potential cutoff thresholds for the GCT: ≥130 mg/dL, ≥135 mg/dL, and ≥140 mg/dL. The investigators found that the optimal cutoff for the 1-hour 50-g GCT screening was ≥135 mg/dL. The data revealed that the 130 mg/dL cutoff did not show any additional predictive value, yet increased the test positive rate. The 140 mg/dL cutoff would have failed to identify 6.5% of patients with GDM.
"With the increasing prevalence of twin pregnancies, understanding how to better screen for GDM is important in this population because of the unique circumstances that may put this group at increased risk for development of insulin resistance, as well as their altered physiology, which would limit the ability to extrapolate from data derived from singleton pregnancies," says investigator Nathan S. Fox, MD, Associate Clinical Professor, Obstetrics, Gynecology and Reproductive Science, Icahn School of Medicine at Mount Sinai. "We found that the optimal GCT cutoff appears to be ≥ 135 mg/dL. This cutoff yielded 100% sensitivity with only a 28.6% test positive rate."
While early detection and screening are essential for effective treatment and control of GDM, unnecessary follow-up testing can cause mental stress for the mother and result in additional out-of-pocket expenditures. "As opposed to a cutoff of ≥130 mg/dL, a cutoff of ≥135 mg/dL could potentially decrease cost and anxiety, without decreasing the sensitivity of the test," explains Dr. Fox.
For now, this study represents an important first step in addressing the distinctive differences between GDM in twin and singleton pregnancies, but more research is needed to fully develop guidelines to better serve mothers carrying twins. "There is much more to learn regarding GDM in twin pregnancies that could be addressed with future prospective studies," concludes Dr. Fox. "More research is needed in twin pregnancies to confirm this finding in other populations, as well as to establish the optimal GDM screening and treatment paradigm in twin pregnancies."
Notes for editors
"Screening approach for gestational diabetes in twin pregnancies," by Andrei Rebarber, MD; Cara Dolin, MD; Jessica C. Fields, BA; Daniel H. Saltzman, MD; Chad K. Klauser, MD; Simi Gupta, MD; Nathan S. Fox, MD (DOI: http://dx.doi.org/10.1016/j.ajog.2014.08.030), online in advance of the American Journal of Obstetrics & Gynecology, Volume 211, Issue 6 (December 2014), published by Elsevier.
Full text of the article is available to credentialed journalists upon request. Contact Eileen Leahy at +1 732 238 3628 or firstname.lastname@example.org to obtain a copy. Journalists wishing to schedule interviews with the authors should contact Dr. Nathan S. Fox at email@example.com.
About the American Journal of Obstetrics
The American Journal of Obstetrics & Gynecology (www.AJOG.org), known as "The Gray Journal," presents coverage of the entire spectrum of the field, from the newest diagnostic procedures to leading-edge research. The Journal provides comprehensive coverage of the specialty, including maternal-fetal medicine, reproductive endocrinology/infertility, and gynecologic oncology. It also publishes the annual meeting papers of several of its 7 sponsoring societies, including the Society for Maternal-Fetal Medicine and the Society of Gynecologic Surgeons.
The American Journal of Obstetrics & Gynecology's 2013 Impact Factor is 3.973. The journal now ranks second in Eigenfactor score, and continues to be first in total citations and the number 5 journal in the Obstetrics & Gynecology category according to the 2013 Journal Citation Reports®, published by Thomson Reuters.
The Journal's standard of excellence and continued success can be attributed to the strong leadership of Editors-in-Chief Ingrid Nygaard, MD, MS, and Roberto Romano, MD, DMedSci, and their outstanding nationally and internationally recognized editorial board and reviewers. The journal has also been recognized as one of the 100 most influential journals in Biology & Medicine over the last 100 years, as determined by the BioMedical & Life Sciences Division of the Special Libraries Association (2009).
Elsevier is a global information analytics business that helps scientists and clinicians to find new answers, reshape human knowledge, and tackle the most urgent human crises. For 140 years, we have partnered with the research world to curate and verify scientific knowledge. Today, we’re committed to bringing that rigor to a new generation of platforms. Elsevier provides digital solutions and tools in the areas of strategic research management, R&D performance, clinical decision support, and professional education; including ScienceDirect, Scopus, SciVal, ClinicalKey and Sherpath. Elsevier publishes over 2,500 digitized journals, including The Lancet and Cell, 39,000 e-book titles and many iconic reference works, including Gray's Anatomy. Elsevier is part of RELX, a global provider of information-based analytics and decision tools for professional and business customers. www.elsevier.com
+1 732 238 3628