Assessing the risk of gestational diabetes in twin gestation.

This study examines the hypothesis that twin gestation is a risk factor for gestational diabetes. In a retrospective analysis, the incidence of gestational diabetes in twin and singleton pregnancies was determined in groups matched for maternal age, weight, and parity. One-hour oral glucose challenge tests (50 g) were used to screen 9185 pregnant women. Gestational diabetes was diagnosed when abnormal screens (> or = 130 mg/dL) were followed by two or more abnormal values on a 3-hour (100 g) glucose tolerance test using National Diabetes Data Group (NDDG) criteria. A twin gestation was identified in 1.5% (138/9185) of the pregnancies. Gestational diabetes was diagnosed in 5.8% (8/138) and 5.4% (439/9047) of the twin and singleton pregnancies, respectively. The incidence of gestational diabetes is similar for singleton and twin gestations.