The American Diabetes Association no longer recommends that pregnant women with low risk factors be screened for gestational diabetes mellitus. However, this recommendation was not based on outcome data confirming the safety of this approach. To address this concern, Moses and colleagues conducted a study to determine the prevalence of gestational diabetes and the pregnancy outcomes in women with low risk factors compared with other women with gestational diabetes.
A total of 2,907 Australian women in the third trimester of a singleton pregnancy were screened for gestational diabetes with a 75-g glucose load after an overnight fast two hours after the load was administered. Women were considered at low risk if they were younger than 25 years, had a body mass index of less than 25 kg per m2 and were from a Caucasian background.
The study population included 573 women who were considered at low risk. Of these, 16 women (2.8 percent) had gestational diabetes. This represented 8.7 percent of all women identified with diabetes in this study. If women with a family history of diabetes were excluded from the low-risk category, 2.5 percent of low-risk women were found to have gestational diabetes. If the definition of low body mass index is expanded to include women at less than 27 kg per m2, 9.8 percent of the women determined to have gestational diabetes would have been from this low-risk group. There were no differences in birth weight, morbidity or rates of emergency cesarean section in women from the low-risk group compared with other women with gestational diabetes.
The authors conclude that although there is less risk of gestational diabetes in low-risk women, the prevalence is still high enough to make testing for gestational diabetes worthwhile. Furthermore, low-risk women with gestational diabetes are at equal risk for complications. Therefore, the authors believe that screening pregnant women with low risk factors for gestational diabetes is still warranted in the community they studied. The recommendation not to test women from a low-risk group requires further evaluation in different populations before it can be endorsed.
editor's note: In this Australian community, a significant number of women with gestational diabetes would have been missed if all pregnant women were not screened. The epidemiology of gestational diabetes may be different in the United States. However, as was the case in Australia, even if the prevalence of diabetes is small in low-risk women in the United States, it may not be insignificant. Therefore, family physicians should be cautious about adopting the American Diabetes Association recommendations for selective screening.—c.k.