FRIDAY, May 22, 2026 (HealthDay News) -- Having a failed glucose challenge test (GCT) concentration without gestational diabetes mellitus (GDM) is associated with a higher risk for preterm birth and large for gestational age (LGA), according to a study published in the May issue of The American Journal of Clinical Nutrition.
Amrita Arcot, Ph.D., from The Pennsylvania State University in University Park, and colleagues examined the relationships between GCT concentrations and GDM with fetal growth and gestational age at birth in a retrospective cohort study using medical record data from 10,899 pregnancies where the placenta was sent for pathology. Glucose groups were categorized as pass GCT/no GDM (control), fail GCT/no GDM, and GDM.
Overall, 5 percent of the placentas sent to pathology were from pregnancies diagnosed with GDM. The researchers found that compared with control, the fail GCT/no GDM and GDM groups had a marginally higher birth weight z-score (adjusted mean difference, 0.14 and 0.19, respectively). A nearly three-day mean difference in gestational age was seen for the GDM group (−2.88). The risks for LGA and preterm birth were 41 and 27 percent higher for patients in the fail GCT/no GDM group; the risk for LGA was 71 percent higher for patients in the GDM group, but the risk for preterm birth was not significantly different.
"The current cutoffs for glucose values are helpful to make a diagnosis of gestational diabetes, but glucose values are on a continuum, and -- based on these results -- clinical outcomes might also be on a continuum," coauthor Kelly Gallagher, Ph.D., also from The Pennsylvania State University, said in a statement.
