Gestational Diabetes: Does it Exist?

Available for download in Word Document format

There is not universal agreement around the world as to the existence of gestational diabetes, which is carbohydrate intolerance with onset or first recognition during pregnancy. No population-based study is available to demonstrate a benefit from universal screening. Nevertheless, a number of studies have suggested increased perinatal mortality and morbidity with undiagnosed and untreated gestational diabetes. Reported morbidities include fetal macrosomia, operative delivery and birth trauma, neonatal hypoglycemia, and possibly obesity and diabetes in the offspring over the long term. While normalization of circulating glucose levels has been shown to lower the likelihood of many of the immediate problems, it is not clear whether intervention during pregnancy can prevent these longer-term problems.

There is also not complete agreement regarding the proper screening procedure and diagnostic test for gestational diabetes. Screening may consist of the taking of a history to look for risk factors for gestational diabetes, or the administration of a glucose challenge (usually 50 grams) and measurement of circulating glucose one hour later, or the measurement of a fasting or random glucose level. In the US and some parts of Europe a 100 gram, 3-hour diagnostic test is most common, whereas in much of the rest of the world a 75-gram, 2-hour test is utilized. In 1998 the Fourth International Workshop-Conference on gestational Diabetes recommended the following diagnostic criteria (plasma, enzymatic method of analysis).

The quality of data supporting these various approaches is not as high as would be desirable. Universally agreed upon diagnostic criteria, based on pregnancy outcomes in well-controlled studies from around the world, would be most helpful.

References:

Reference
METZGER BE, COUSTAN DR and THE ORGANIZING COMMITTEE: Summary and Recommendations of the Fourth International Workshop-Conference on Gestational Diabetes Mellitus. Diab Care 21 (Suppl 2):B161-B167, 1998.