OBJECTIVE: To examine the relationship between varying degrees of maternal hyperglycemia and pregnancy outcomes.
METHODS: This was a secondary analysis of a treatment trial for mild gestational diabetes including four cohorts: 1) 473 women with untreated mild gestational diabetes; 2) 256 women with a positive 50-g screen and one abnormal oral glucose tolerance test (OGTT) value; 3) 675 women with a positive screen and no abnormal OGTT values; and 4) 437 women with a normal 50-g screen. Groups were compared by test of trend for a composite perinatal outcome (neonatal hypoglycemia, hyperbilirubinemia, elevated cord C-peptide level, and perinatal trauma or death), frequency of large for gestational age neonates, shoulder dystocia, and pregnancy-related hypertension. Three-hour OGTT levels (fasting, 1-, 2-, and 3-hour) levels were divided into categories and analyzed for their relationship to perinatal and maternal outcomes.
RESULTS: There were significant trends by glycemic status among the four cohorts for the composite and all other outcomes (P<.001). Analysis for trend according to OGTT categories showed an increasing relationship between fasting and all postload levels and the various outcomes (P<.05). Fasting glucose 90 mg/dL or greater and 1 hour 165 mg/dL or greater were associated with an increased risk for the composite outcome (odds ratios and 95% confidence intervals of 2.0 [1.03–4.15] and 1.46 [1.02–2.11] to 1.52 [1.08–2.15] for the fasting and 1 hour, respectively). A 1 hour glucose 150 mg/dL or greater was associated with an increased risk for large for gestational age (odds ratios, 1.8 [1.02–3.18] to 2.35 [1.35–4.14]); however, 2- and 3-hour glucose levels did not increase the risk for the composite or large for gestational age until well beyond current gestational diabetes diagnostic thresholds.
CONCLUSION: A monotonic relationship exists between increasing maternal glycemia and perinatal morbidity. Current OGTT criteria require reevaluation in determining thresholds for the diagnosis and treatment of gestational diabetes.
LEVEL OF EVIDENCE: II
Even minor degrees of carbohydrate intolerance may be associated with untoward perinatal outcomes.
From the Department of Obstetrics and Gynecology, The Ohio State University, Columbus, Ohio; The George Washington University Biostatistics Center, Washington, DC; the Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland; the Departments of Obstetrics and Gynecology at Brown University, Providence, Rhode Island; The University of Texas Health Science Center at Houston, Houston, Texas; The University of Texas Southwestern Medical Center, Dallas, Texas; Columbia University, New York, New York; University of Utah, Salt Lake City, Utah; University of Alabama at Birmingham, Birmingham, Alabama; University of North Carolina, Chapel Hill, North Carolina; Drexel University, Philadelphia, Pennsylvania; Case Western Reserve University–MetroHealth Medical Center, Cleveland, Ohio; Wake Forest University Health Sciences, Winston-Salem, North Carolina; University of Texas Medical Branch, Galveston, Texas; University of Pittsburgh, Pittsburgh, Pennsylvania; Wayne State University, Detroit, Michigan; Northwestern University, Chicago, Illinois; and Oregon Health and Science University, Portland, Oregon.
*For a list of other members of the NICHD MFMU, see the Appendix online at http://links.lww.com/AOG/A215.
Supported by grants from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (HD27915, HD34116, HD40485, HD34208, HD27869, HD40500, HD40560, HD34136, HD40544, HD27860, HD40545, HD53097, HD21410, HD27917, HD40512, HD53118, HD36801), General Clinical Research Centers Grant (M01-RR00034), and the National Center for Research Resources (UL1-RR024989, M01-RR00080, UL1-RR025764, C06-RR11234) and does not necessarily represent the official views of the National Institute of Child Health and Human Development or the National Institutes of Health.
The authors thank Julia Zachary for data management; Francee Johnson, RN, Joanne Tillinghast, RN, and Susan Tolivaisa for coordination between clinical research centers; Elizabeth Thom, PhD, for study design, data management, statistical analysis, and manuscript development; Steven G. Gabbe, MD, and Menachem Miodovnik, MD, for study design and protocol development; and Roger Newman, MD, for study design.
Presented in part at the 30th annual meeting of the Society for Maternal–Fetal Medicine, February 1–6, 2010, Chicago, Illinois.
Dr. Spong, Associate Editor of Obstetrics & Gynecology, was not involved in the review or decision to publish this article.
Corresponding author: Mark B. Landon, MD, The Ohio State University College of Medicine, Department of Obstetrics and Gynecology, 395 W 12th Avenue, Suite 572, Columbus, OH 43210; e-mail: Mark.Landon@osumc.edu.
Financial Disclosure The authors did not report any potential conflicts of interest.