【對GDM領域有大貢獻的建議】
澳洲新南威爾斯臥龍岡、東南雪梨和伊拉瓦拉地區(South Eastern Sydney and Illawarra Area)健康服務的Robert G. Moses醫師在編輯評論中指出，新的IADPSG建議對於我們對GDM的知識與暸解有顯著貢獻，但是對這個迫切性問題的解決方式在未來仍然有些問題。
Guidelines Issued for Diagnosis and Classification of Hyperglycemia in Pregnancy
By Laurie Barclay, MD
Medscape Medical News
March 1, 2010 — The International Association of Diabetes and Pregnancy Study Groups (IADPSG) has issued recommendations on the diagnosis and classification of hyperglycemia in pregnancy. The new guidelines for gestational diabetes mellitus (GDM) are published in the March issue of Diabetes Care.
Although overt diabetes in pregnant women predicts adverse maternal and fetal outcomes, the effect of less severe degrees of hyperglycemia on adverse outcomes is poorly understood.
"As currently defined, GDM includes a subgroup with more severe hyperglycemia (similar to that seen in preexisting diabetes) that presents special issues concerning management during pregnancy and postpartum follow-up," the IADPSG Consensus Panel writes.
"The issues raised by inclusion of this subgroup with those with GDM are of greater concern because of the rising prevalence of obesity, type 2 diabetes, and other metabolic disturbances among younger age groups. The HAPO [Hyperglycemia and Adverse Pregnancy Outcome] study was designed to clarify risks of adverse outcome associated with degrees of maternal glucose intolerance less severe than those with overt diabetes during pregnancy."
In the HAPO study, there were continuous graded relationships with increasing maternal hyperglycemia for primary outcomes of birth weight greater than the 90th percentile, cesarean delivery, neonatal hypoglycemia, and cord C-peptide greater than the 90th percentile.
Recommendations for Hyperglycemia in Pregnancy
Specific recommendations for identifying and diagnosing hyperglycemic disorders in pregnancy include the following:
At the first prenatal visit, all or only high-risk women should undergo testing of fasting plasma glucose (FPG), hemoglobin A1c, or random plasma glucose, based on the background frequency of abnormal glucose metabolism in the population and on local circumstances.
Thresholds for diagnosis of overt diabetes during pregnancy are FPG of at least 7.0 mmol/L (126 mg/dL); hemoglobin A1c level of at least 6.5% (Diabetes Control and Complications Trial/UK Prospective Diabetes Study standardized); or random plasma glucose at least 11.1 mmol/L (200 mg/dL), plus confirmation.
If this testing result indicates overt diabetes, treatment and follow-up should be the same as for preexisting diabetes. If testing is not diagnostic of overt diabetes and FPG is at least 5.1 mmol/L (92 mg/dL) but less than 7.0 mmol/L (126 mg/dL), GDM should be diagnosed.
If FPG is less than 5.1 mmol/L (92 mg/dL), the patient should be tested for GDM from 24 to 28 weeks of gestation with a 75-g oral glucose tolerance test (OGTT).
To diagnose GDM at 24 to 28 weeks of gestation, a 2-hour, 75-g OGTT should be performed after overnight fast on all women not previously found to have overt diabetes or GDM during testing earlier in this pregnancy.
Overt diabetes is diagnosed if fasting plasma glucose level is at least 7.0?mmol/L (126 mg/dL). GDM is diagnosed if 1 or more values equals or exceeds thresholds of FPG of 5.1 mmol/L (92 mg/dL), 1-hour plasma glucose level of 10.0 mmol/L (180 mg/dL), and/or a 2-hour plasma glucose level of 8.5?mmol/L (153 mg/dL). Normal test results are defined as all values on OGTT less than these thresholds.
The panel concluded that insufficient studies have been done to determine whether there is a benefit of generalized testing to diagnose and treat GDM before the usual window of 24 to 28 weeks of gestation.
All women diagnosed with GDM or overt diabetes during pregnancy should undergo postpartum glucose testing.
The consensus panel notes that in some regions and/or countries, the recommendations may be a significant departure from long-established practices. In most areas, use of this detection strategy will substantially increase the frequency of hyperglycemic disorders in pregnancy. However, the panel notes that this is consistent with the high prevalence of obesity and disorders of glucose metabolism in the general population of young adults and with the increasing prevalence of GDM and preexisting overt diabetes in pregnant women.
Further Trials Needed
"The HAPO study was a basic epidemiological investigation that for the first time conclusively identified strong continuous associations of maternal glucose levels below those diagnostic of diabetes with several perinatal outcomes," the study authors conclude.
"It was not a clinical trial, but two randomized controlled trials of treatment of mild GDM have been carried out successfully in participants with glucose values that overlap with the thresholds recommended in this report. However, it is likely that additional well-designed randomized controlled trials and other clinical studies will be needed to determine 1) cost-effective therapeutic strategies for treatment of GDM diagnosed by the IADPSG Consensus Panel–recommended criteria; 2) optimal glycemic treatment targets; 3) appropriate follow-up of mothers to determine risks for later development of diabetes, other metabolic disorders, or CVD [cardiovascular disease] risk factors; and 4) follow-up of children to assess potential associations of maternal glycemia with long-term risks of obesity, altered glucose metabolism, and CVD risk factors."
Recommendations Great Contribution to GDM Field
In an accompanying editorial, Robert G. Moses, MD, from the South Eastern Sydney and Illawarra Area Health Service in Wollongong, New South Wales, Australia, notes that the new IADPSG recommendations are "a significant contribution to our knowledge and understanding of GDM" but that "solutions of an immediate problem raise questions for the future."
"Could the identification of a greater number of women at risk of an adverse pregnancy outcome itself cause harm?" Dr. Moses writes. "It is well documented that a diagnostic category of GDM, irrespective of the glucose control achieved, in some instances is likely to result in increased interventions, earlier delivery, an increased caesarean section rate, and a higher number of babies being admitted to special care nurseries. Could these real hazards offset some of the potential advantages?"
The HAPO study was funded by National Institute of Child Health and Human Development; the National Institute of Diabetes, Digestive and Kidney Diseases; and the American Diabetes Association. One of the review authors received research support to participate in a trial of the noninvasive Scout device and has received research support from Veralight.
Dr. Moses has disclosed no relevant financial relationships.
