Objective: The objective of this study was to examine the relationship between positive glucose challenge test (GCT) values and perinatal outcomes stratified by maternal body mass index (BMI).
Study design: Retrospective cohort of singleton gestations with a GCT performed at >20 weeks and documented BMI at entry to care. Subjects were classified by GCT level and BMI. Primary outcomes included large for gestational age (LGA), macrosomia, shoulder dystocia, and pregnancy-induced hypertension. Cochran-Armitage tests for trend and logistic regression were used to compare the GCT categories.
Results: A total of 14,525 women met enrollment criteria-8,521 with a GCT < 120 mg/dL and 6,004 with a GCT ≥ 120 mg/dL. When BMI < 25 kg/m(2) was considered, the risks were not increased at any level of GCT for any outcome. However, for subjects with BMI ≥ 25 kg/m(2), the risk of LGA for a GCT 130 to 134 mg/dL was increased, but not at GCT of 135 to 139 mg/dL (p < 0.001). Similar, but nonsignificant, trends were observed for macrosomia and shoulder dystocia.
Conclusion: Increasing GCT is associated with adverse outcomes primarily in women with a BMI ≥ 25 kg/m(2). Women with a BMI ≥ 25 kg/m(2) and a GCT 135 to 140 mg/dL appear to have less risk of LGA than women with GCT 130 to 134 mg/dL, suggesting a possible effect of diagnosing and treating gestational diabetes mellitus in this group.
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