Objective: To estimate the screening rate and prevalence of gestational diabetes mellitus (GDM) and the screening rate and prevalence of postpartum diabetes, in a large, national sample of pregnant women. We also estimated the potential effects of the new International Association of Diabetes and Pregnancy Study Groups recommendations, which replace the 100-g oral glucose tolerance test (OGTT) with the 75-g OGTT, on GDM prevalence and gestational plasma glucose testing practices.
Methods: We identified pregnant women who used the laboratory services of Quest Diagnostics and who were screened for GDM and were tested postpartum. Gestational diabetes mellitus prevalence was calculated according to the current American Diabetes Association/ Carpenter-Coustan criteria, and the new International Association of Diabetes and Pregnancy Study Groups criteria.
Results: Sixty-eight percent (632,820/924,873) of pregnant women aged 25 to 40 (ie, those not in a low-risk age group) who utilized the services of Quest Diagnostics during this study were screened for GDM. Of the entire adult pregnant population (ages 18-40) who received GDM screening, 5% (40,955/842,993) had positive test results under the current criteria. Nineteen percent (4,486/23,299) of those with GDM received postpartum diabetes testing within a 6-month period. Ninety percent (148,749/166,085) of all confirmatory GDM tests performed on pregnant women at Quest Diagnostics were the 100-g OGTT. The number of women with GDM after receiving the 75-g OGTT would have doubled under the International Association of Diabetes and Pregnancy Study Groups criteria.
Conclusion: Many women may not be receiving GDM screening during pregnancy. Postpartum diabetes screening rates after pregnancy remain low. Adoption of the new International Association of Diabetes and Pregnancy Study Groups criteria would require a significant change in current clinical practice.
Level of evidence: III.