Effects of Fasting on the Results of Fifty-Gram Test in GDM Screening

Document Type : Original Article

Authors

1 Assistant Professor of Obstetrics and Gynecology, Women’s Health Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.

2 Associate Professor of Obstetrics and Gynecology, Women’s Health Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.

3 Assistant Professor of Obstetrics and Gynecology, Fellowship of Perinatology, Imam Khomeini Hospital, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.

4 Assistant Professor of Neonatology, Neonatal Subspecialist, Faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran.

Abstract

Introduction: Gestational diabetes mellitus (GDM) refers to diagnosing of carbohydrate intolerance during pregnancy which may cause some serious fetal and maternal complications. GCT (fifty-gram glucose tolerance test) is the first test for GDM screening which is done without regarding of fasting condition. While prevalence of GDM is 2-5%, the result of this test is positive in 14-18% of pregnant women. Thus, those with positive results are screened by a three-hour hundred-gram glucose tolerance test (GTT). Execution of this test requires 8-14 hours fasting and four-times blood sampling in which the patient incurs a lot of time, cost and stresses. If GDM cases are reduced by execution of GTT after ten-hour fasting, a hundred-gram GTT is prevented in many patients. The aim of this survey is evaluation effects of fasting on results of fifty-gram oral glucose challenge test in GDM screening
Methods: A total of 130 pregnant women who met the inclusion criteria with gestational age of 24 to 32 weeks and were hospitalized in Imam Reza hospital from 2008 to 2009 participated in this study. They were randomly entered into fasting group (80 cases) or non-fasting group (50 cases). After one hour receiving fifty-gram oral glucose, blood sampling was taken from all of them. Then, the level of blood glucose was measured and compared between two groups by T test, Mann Whitney, Chi Square tests and SPSS software version 13. P<0.05 was determined significant.
Results: T-test evaluation shows no statistical significant relation between fasting status and the result of screening (P=0.89). But, based on Chi Square test, fasting and non-fasting group were statistically different in terms of mean blood glucose (P=0.03).
Conclusion: In GDM screening test, the mean level of blood glucose reduces in fasting status.

Keywords


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