Poster session II Clinical obstetrics, diabetes, labor, medical-surgical-disease, physiology/endocrinology, prematurity: Abstracts 237 - 386| Volume 208, ISSUE 1, SUPPLEMENT , S118-S119, January 01, 2013

259: Outcomes after implementation of first trimester screening for gestational diabetes


      Acknowledging recommendations from the IADPSG, our institution recently transitioned from traditional third-trimester (T3) to first-trimester (T1) screening for gestational diabetes (GDM). This new protocol has doubled the rate of diagnosis of GDM. Our objective was to describe and compare perinatal outcomes based on the mode and timing of diagnosis.

      Study Design

      This retrospective cohort study evaluated patients from our institution diagnosed with GDM from July-December 2011. Beginning in July, new early screening guidelines were initiated which included a diagnosis of GDM if T1 HbA1c ≥ 5.7% or fasting plasma glucose (FPG) was ≥ 92 mg/dL. If both HbA1c and FPG were normal, an abnormal 2-hour glucose tolerance test (GTT) at 24-28 weeks was diagnostic of GDM. However, during this 6-month transition period, many providers continued traditional T3 two-step screening for GDM with a 1-hour glucose challenge test (GCT) followed by a 3-hour GTT. We compared differences in outcomes between T1 and T3 screening groups and within the 4 different subgroups of those diagnosed by T1 screening (HbA1c, FPG, both HbA1c and FPG, or 2-hour GTT). Data regarding GDM types A1 and A2, birthweight (BW), and ponderal index (PI) were abstracted.


      A total of 120 patients were diagnosed with GDM during the study period. Sixty-three (53%) had T1 screening: 23 had elevated HbA1c alone, 9 had elevated FPG alone, 11 had both HbA1c and FPG elevated, and 20 had normal HbA1c and FPG and a subsequently abnormal 2-hour GTT. Fifty-seven (47%) patients were diagnosed using traditional T3 two-step screening. There were no significant differences between T1 or T3 screening groups or within T1 diagnostic subgroups with respect to GDM type (A1 vs. A2), BW, or PI (table).
      Tabled 1Gestational diabetes outcomes based on mode of diagnosis
      Table thumbnail grr20


      GDM diagnosed with T1 HbA1c, FPG, both HbA1c and FPG, or 2-hour GTT results in similar ratios of subtypes (A1 vs A2) as traditional T3 screening. A prospective study is needed to accurately ascertain whether earlier diagnosis of GDM leads to improved neonatal outcomes.