Recommendations on the Diagnosis and Classification of Hyperglycemia in Pregnancy

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Diagnosis and Classification of
Hyperglycemia in Pregnancy

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American Diabetes Association (ADA) Recommendations on the Diagnosis and Classification of Hyperglycemia in Pregnancy [1]

The International Association of Diabetes and Pregnancy Study Groups (IADPSG) new recommendations include a two phase strategy for diagnosis and classification of hyperglycemia in pregnancy that consists of early screening for overt diabetes, and implementation of a 75 -gram glucose oral glucose tolerance test OGTT for the diagnosis of gestational diabetes (GDM).

The first phase of the strategy was arrived at by consensus opinion and is intended to identify women with overt diabetes at their first prenatal visit by early testing in populations with a high prevalence of type 2 diabetes. It was not deemed feasible to recommend a single test to use exclusively. Although, many members of the consensus panel favored using A1C for the detection of overt diabetes in pregnancy, the prevalence of hemoglobin variants in some populations as well as cost and standardization issues were apparently concerns with A1C testing.

The second phase of the strategy involves performance of a 2-h 75-g OGTT at 24 to 28 weeks' on all women not previously found to have overt diabetes or GDM during testing earlier in their current pregnancy. The threshold values on the 2-h 75-g OGTT for the diagnosis of GDM were arrived at after review and consideration of the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study data. These threshold values are glucose values at which there is an increased odds for birth weight, cord C-peptide, and percent body fat to be greater than 90th percentile. The panel concluded that there have been insufficient studies performed to know whether there is a benefit of generalized testing to diagnose and treat GDM before the usual window of 24–28 weeks’ gestation.

Two Phase Strategy:

I. First Prenatal Visit*

Measure fasting plasma glucose (FPG), A1C, or random plasma glucose on all or only high-risk women.

The decision to perform blood testing for evaluation of glycemia on all pregnant women or only on women with characteristics indicating a high risk for diabetes is to be made on the basis of the background frequency of abnormal glucose metabolism in the population and on local circumstances.

Table1

Measure of glycemia	Consensus threshold for diagnosis of overt diabetes
FPG‡	> 7.0 mmol/L (126 mg/dl)
A1C‡	> 6.5% (DCCT/UKPDS standardized)
Random plasma glucose	> 11.1 mmol/l (200 mg/dl) + confirmation §
If results indicate overt diabetes, then treatment and follow-up as for preexisting diabetes If results not diagnostic of overt diabetes and fasting plasma glucose > 5.1 mmol/l (92 mg/dl) but < 7.0 mmol/l (126 mg/dl), then diagnose as gestational diabetes (GDM) If results not diagnostic of overt diabetes and fasting plasma glucose < 5.1 mmol/l (92 mg/dl), then test for GDM from 24 to 28 weeks’ gestation with a 75-g OGTT
‡ One of these must be met to identify the patient as having overt diabetes in pregnancy. § If a random plasma glucose is the initial measure, the tentative diagnosis of overt diabetes in pregnancy should be confirmed by FPG or A1C using a DCCT/ UKPDS-standardized assay.

The Sweet Success Program of California recommends that individuals with an A1C of 5.7-6.4% (prediabetes-glucose intolerance) should be informed of their increased risk for diabetes , and should receive early diet education and exercise modifications similar to patients with GDM [2].

II. At 24 to 28 weeks'

Perform 2-h 75-g OGTT after an overnight fast on all women not previously found to have overt diabetes or GDM during testing earlier in their current pregnancy. To be applied to women without known diabetes before pregnancy.

Table 2

Threshold values for diagnosis of GDM
	Glucose concentration threshold*

Glucose measure	mmol/l	mg/dl

FPG	5.1	92
1-h plasma glucose	10.0	180
2-h plasma glucose	8.5	153
*One or more of these values from a 75-g OGTT must be equaled or exceeded for the diagnosis of GDM. Diagnose as overt diabetes if fasting plasma glucose > 7.0 mmol/l (126 mg/dl) Diagnose GDM if one or more values equals or exceeds the thresholds indicated above (Table2) Diagnose as normal if all values on the OGTT are less than the thresholds indicated above (Table 2)

Postpartum glucose testing should be performed for all women diagnosed with overt diabetes during pregnancy or GDM

1. Condensed from: International Association of Diabetes and Pregnancy Study Groups Consensus Panel. International association of diabetes and pregnancy study groups recommendations on the diagnosis and classification of hyperglycemia in pregnancy. Diabetes Care. 2010 Mar;33(3):676-82. PMID: 20190296

2. Guidelines for Diagnosis of Hyperglycemia in Pregnancy – 2011
http://www.cdph.ca.gov/programs/cdapp/Documents/MO-CDAPP-HyperglycemiaAlgorithm-7-18-11.pdf
Accessed 6/20/2012

Reprinted with permission of The American Diabetes Association.