DETECTION AND DIAGNOSIS OF GDM - Diagnosing And Managing Diabetes


* Screen for diabetes in pregnancy using risk factor analysis and, if appropriate, use of an OGTT. (C)
* Women with GDM should be screened for diabetes 6??12 weeks postpartum and should be followed up with subsequent screening for the development of diabetes or pre-diabetes. (E)

Risk assessment for GDM should be undertaken at the first prenatal visit. Women with clinical characteristics consistent with a high risk for GDM (those with marked obesity, personal history of GDM, glycosuria, or a strong family history of diabetes) should undergo glucose testing as soon as possible. An FPG 126 mg/dl or a casual plasma glucose 200 mg/dl meets the threshold for the diagnosis of diabetes and needs to be confirmed on a subsequent day unless unequivocal symptoms of hyperglycemia are present. High-risk women not found to have GDM at the initial screening and average-risk women should be tested between 24 and 28 weeks of gestation. Testing should follow one of two approaches:

Text continued below

* One-step approach: perform a diagnostic 100-g OGTT
* Two-step approach: perform an initial screening by measuring the plasma or serum glucose concentration 1 h after a 50-g oral glucose load (glucose challenge test) and perform a diagnostic 100-g OGTT on that subset of women exceeding the glucose threshold value on the glucose challenge test. When the two-step approach is used, a glucose threshold value 140 mg/dl identifies 80% of women with GDM, and the yield is further increased to 90% by using a cutoff of 130 mg/dl.

Diagnostic criteria for the 100-g OGTT are as follows: 95 mg/dl fasting, 180 mg/dl at 1 h, 155 mg/dl at 2 h, and 140 mg/dl at 3 h. Two or more of the plasma glucose values must be met or exceeded for a positive diagnosis. The test should be done in the morning after an overnight fast of 8??14 h. The diagnosis can be made using a 75-g glucose load, but that test is not as well validated for detection of at-risk infants or mothers as the 100-g OGTT.

Low-risk status requires no glucose testing, but this category is limited to those women meeting all of the following characteristics:

* Age <25 years.
* Weight normal before pregnancy.
* Member of an ethnic group with a low prevalence of GDM.
* No known diabetes in first-degree relatives.
* No history of abnormal glucose tolerance.
* No history of poor obstetric outcome.


1.  Bode BW (Ed.): Medical Management of Type 1 Diabetes. 4th ed. Alexandria, VA, American Diabetes Association, 2004
2.  Zimmerman BR (Ed.): Medical Management of Type 2 Diabetes. 4th ed. Alexandria, VA, American Diabetes Association, 1998
3.  Kilingensmith G (Ed.): Intensive Diabetes Management.  3rd ed.  Alexandria, VA, American Diabetes Association, 2003
4.  The Expert Committee on the Diagnosis and Classification of Diabetes Mellitus: Report of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus. Diabetes Care 20:1183-1197, 1997
4a.World Health Organization:  Diabetes Mellitus: Report of a WHO Study Group. Geneva, World Health Org., 1985 (Tech. Rep. Ser., no. 727)
5.  The Expert Committee on the Diagnosis and Classification of Diabetes Mellitus: Follow-up report on the diagnosis of diabetes mellitus. Diabetes Care 26:3160 - 3167, 2003
6.  Tuomilehto J, Lindstrom J, Eriksson JG, Valle TT, Hamalainen H, Ilanne-Parikka P, Keinanen-Kiukaaniemi S, Laakso M, Louheranta A, Rastas M, Salminen V, Uusitupa M: Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance. N Engl J Med 344:1343-1350, 2001
7.  Pan XR, Li GW, Hu YH, Wang JX, Yang WY, An ZX, Hu ZX, Lin J, Xiao JZ, Cao HB, Liu PA, Jiang XG, Jiang YY, Wang JP, Zheng H, Zhang H, Bennett PH, Howard BV: Effects of diet and exercise in preventing NIDDM in people with impaired glucose tolerance: the DaQing IGT and Diabetes Study. Diabetes Care 20:537- 544, 1997
8.  The Diabetes Prevention Program Research Group:  Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med 346:393- 403, 2002
9.  Chiasson JL, Josse RG, Gomis R, Hanefeld M, Karasik A, Laakso M: Acarbose for prevention of type 2 diabetes mellitus: the STOP-NIDDM randomized trial. Lancet 359:2072-2077, 2002
10.  Sjostrom L, et al: XENDOS ( Xenical in the prevention of diabetes in obese subjects):  a landmark study.  Poster presented at the International Congress on Obesity (ICO), San Paulo, Brazil, 2002
11.  Buchanan TA, Xiang AH, Peters RK, Kjos SL, Marroquin A, Goico J, Ochoa C, Tan S, Berkowitz, Hodis HN, Azen SP: Preservation of pancreatic β-cell function and prevention of type 2 diabetes by pharmacological trewatment of insulin resistance in high-risk hispanic women. Diabetes 51:2796 -2803, 2002
12.  Engelgau ME, Narayan KMV, Herman WH:  Screening for type 2 diabetes (Technical Review).  Diabetes Care 23:1563-1580, 2000 [erratum appears in Diabetes Care 23:1868 -1869, 2000]
13.  American Diabetes Association: Type 2 diabetes in children and adolescents (Consensus Statement).  Diabetes Care 23:381-389, 2000
14.  American Diabetes Association: Gestational diabetes mellitus (Position Statement). Diabetes Care 27 (Suppl. 1):S88 - S90, 2004
15.  The Diabetes Control and Complications Trial Research Group: The effect of intensive treatment of diabetes on the development and progression of longterm complications in insulin-dependent diabetes mellitus. N Engl J Med 329: 977-986, 1993
16.  The UK Prospective Diabetes Study Group: Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33). Lancet 352: 837- 853, 1998
17.  The UK Prospective Diabetes Study Group: Effect of intensive blood-glucose control with metformin on complications in overweight patients with type 2 diabetes (UKPDS 34). Lancet 352:854 -865, 1998

May 27, 10 • Diabetes mellitus