39: One-step vs two-step screening for gestational diabetes: a randomized controlled trial


      To assess the incidence of gestational diabetes mellitus (GDM) using the International Association of Diabetes in Pregnancy Study Group (IADPSG) criteria (one-step approach) compared to the American College of Obstetrics and Gynecology (ACOG) criteria (two-step approach) for the diagnosis of GDM.

      Study Design

      This is a prospective randomized controlled trial of women presenting for GDM screening. Patients were randomized into universal screening with either the one-step approach—a 2-hour 75g oral glucose tolerance test (OGTT as defined by IADPSG, thresholds 92mg/dl, 180mg/dl, 153 mg/dl), or with the two-step approach— a 50 glucose challenge test (GCT, threshold 135mg/dl) followed by a diagnostic 3-hour 100 g test (OGTT, as defined by Carpenter and Coustan and endorsed by ACOG, thresholds 95mg/dl, 180 mg/dl, 155mg/dl, 140mg/dl). Diagnosis of GDM required the presence of one abnormal value with the one-step approach, and two abnormal values on the second part of the two-step approach. The primary outcome was incidence of GDM.


      A total of 249 women were included in the trial. Of those, 123 were randomized into the one-step approach (2-hour 75g OGTT, IADPSG) and 126 into the two-step approach (1 hour GCT followed by 3 hour 100g OGTT, ACOG). GDM was diagnosed in 10 women (8.1%) in the one-step group, and 7 women (5.5%) in the two-step group (p=0.42). There was no significant difference in the rate of preeclampsia, cesarean section rate, macrosomia, shoulder dystocia, or neonatal hypoglycemia between both groups (figure). There was a significant increase in neonatal hyperbilirubinemia with the one-step approach screening (p=0.04).


      GDM screening with the one-step approach did not significantly increase the incidence of GDM compared with the two-step approach.
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