Can the 3rd Hour Value of 100 g Oral Glucose Tolerance Test Be Ignored in the Diagnosis of Gestational Diabetes Mellitus?

Mehmet Metin Altay
Serdinç Özdoğan
Aytaç Tohma
Sertaç Esin
Okyar Erol
Orhan Gelişen
Melih Akkuş
Sinan Karadeniz
Full Text: PDF


OBJECTIVE: To investigate whether the 3rd hour value of 100 g oral glucose tolerance test (OGTT) can be ignored when diagnosing gestational diabetes.
STUDY DESIGN: During the first 8 months of 2010, 6909 patients between 24 and 28 weeks’ of gestation were screened with 50 g glucose challenge test and 140 mg/dl or higher plasma glucose levels were further evaluated with 100 g OGTT to diagnose gestational diabetes mellitus (GDM). 1195 patients’ test results were acquired for this retrospective study. For the 100 g OGTT fasting plasma glucose cut-off value was 105 mg/dl, 1 hour cut-off value was 190 mg/dl, 2 hour cut-off value was 165 mg/dl and 3 hour cut-off value was 145 mg/dl. Patients with 2 or more values above the cut-off level were diagnosed as GDM.
RESULTS: Out of 1195, 124 patients (10.4%) were diagnosed as having GDM. 65 patients (52.4%) had high values of first and second hours; 33 patients (26.6%) had high values of first, second and third hours; 19 patients (15.4%) had second and third hours high values; 7 patients (5.6%) had first and third hours high values of 100 gr OGTT out of those 124 patients.
CONCLUSION: 79% of the patients were diagnosed with first and second hour test results but 21% of the patients were diagnosed with blood glucose levels above the third hour cut-off level. Thus, considering the difficulties of 100 gr. OGTT, third hour values is of diagnostic value and cannot be ignored.


Gestational diabetes mellitus, Screening, Diagnosis, 100 g oral glucose tolerance test

Copyright (c) 2016 Gynecology Obstetrics & Reproductive Medicine

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.