Objective: To evaluate the accuracy of diagnosing gestational diabetes mellitus (GDM) by a 2-h blood glucose value > or = 9.0 mmol/l in the 75 g oral glucose tolerance test (OGTT). The maternal and neonatal outcome in women with a 2-h blood glucose value just below this limit, 8.0-8.9 mmol/l, is analyzed. The outcome is compared to a randomly selected control group.
Design: A comparative study.
Subjects: There were 223 women in the group with a 2-h value of 8.0 to 8.9 mmol/l in the OGTT. This group was compared to a randomly selected control group of 391 women.
Main outcome measures: Fetal outcome: perinatal mortality, birth weight, respiratory disturbances, symptomatic hypoglycemia, polycythemia, hyperbilirubinemia and traumatic deliveries. Maternal age, body mass index (BMI), pregnancy-induced hypertension (PIH) or preeclampsia and route of delivery.
Results: The women in the group with a 2-h glucose value of 8.0-8.9 mmol/l were, compared to the control group, significantly older, heavier, had a higher BMI, gave birth to heavier children and a significantly increased number of large-for-date infants, while there were no differences in neonatal mortality, morbidity or birth trauma.
Conclusions: This study shows that using the 75 g 2-h OGTT with a B-glucose limit of > or = 9.0 mmol/l instead of > or = 8.0 mmol/l to diagnose GDM during pregnancy has no major adverse effects concerning maternal and neonatal outcome in the borderline interval of 8.0 to 8.9 mmol/l.