Amer J Perinatol 2017; 34(14): 1464-1469
DOI: 10.1055/s-0037-1604243
Original Article
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Predictive Characteristics of Elevated 1-Hour Glucose Challenge Test Results for Gestational Diabetes

Alan T.N. Tita1, Yinglei Lai2, Mark B. Landon3, Susan M. Ramin4, Brian Casey5, Ronald J. Wapner6, Michael W. Varner7, John M. Thorp Jr.8, Anthony Sciscione9, Patrick Catalano10, Margaret Harper11, George R. Saade12, Steve N. Caritis13, Yoram Sorokin14, Alan M. Peaceman15, Jorge E. Tolosa16, for the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Maternal-Fetal Medicine Units (MFMU) Network
  • 1Department of Obstetrics and Gynecology, University of Alabama at Birmingham, Birmingham, Alabama
  • 2The Biostatistics Center, The George Washington University, Washington, District of Columbia
  • 3Ohio State University, Columbus, Ohio
  • 4University of Texas Health Science Center, Houston-Children's Memorial Hermann Hospital, Houston, Texas
  • 5University of Texas Southwestern Medical Center, Dallas, Texas
  • 6Columbia University, New York, New York
  • 7University of Utah, Salt Lake City, Utah
  • 8University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
  • 9Drexel University, Philadelphia, Pennsylvania
  • 10MetroHealth Medical Center, Case Western Reserve University, Cleveland, Ohio
  • 11Wake Forest University Health Sciences, Winston-Salem, North Carolina
  • 12University of Texas Medical Branch, Galveston, Texas
  • 13University of Pittsburgh, Pittsburgh, Pennsylvania
  • 14Wayne State University, Detroit, Michigan
  • 15Northwestern University, Chicago, Illinois
  • 16Oregon Health and Science University, Portland, Oregon
Further Information

Publication History

20 January 2017

08 June 2017

Publication Date:
19 July 2017 (eFirst)


Objective The objective was to estimate the optimal screen-positive 1-hour 50 g glucose challenge test (GCT) threshold for gestational diabetes (GDM) and predictive characteristics of increasing screen-positive GCT threshold values (135–199 mg/dL) for GDM.

Study Design It is a secondary analysis of a multicenter mild GDM study. At 24 to 30 weeks' gestation, women with elevated GCT (135–199 mg/dL) completed a diagnostic 3-hour oral glucose tolerance test (OGTT). A novel change-point analysis method was used to compare the GDM rates for the adjacent GCT values, delineating categories of changing risk such that values within categories have equal risk for GDM. Positive (PPV) and negative (NPV) predictive values for GDM were computed for increasing GCT cut-offs.

Results In 7,280 women with both GCT (135–199 mg/dL) and OGTT results, 4 GDM risk-equivalent GCT categories were identified with escalations at 144, 158, and 174 mg/dL (all p-values <0.05). The PPV for GDM increased from 33 to 64% as GCT increased from 135 to 199 mg/dL, while the NPV decreased from 80 to 67%. PPVs were only 20% and 61% for risk-equivalent categories of 135 to 143 mg/dL and 174 to 199 mg/dL, respectively.

Conclusion Elevated GCT cut-off values between 135 and 143 mg/dL may carry equivalent GDM risk. No threshold GCT value <199 mg/dL alone sufficiently predicts GDM.


This study was presented in part as a poster presentation at the 31st Annual Meeting of the Society for Maternal-Fetal Medicine in San Francisco, CA February 9–12, 2011.