The association between normal 50-g glucose challenge test results and risk for future metabolic morbidities: A retrospective cohort study

Objective: To study the association between normal glucose challenge test (GCT) results during pregnancy and the incidence of future maternal metabolic morbidities. Method: This was a population-based retrospective cohort study conducted between the years 2005 and 2020. The study included all women aged 17–55 years who underwent GCT as part of the routine prenatal care at the Central District of Clalit Health Services, Israel. The highest GCT result per woman was categorized into five study groups: <120 (reference), 120–129, 130–139, 140–149, and ≥150 mg/dL. Adjusted hazard ratios of the study groups for metabolic morbidities were calculated with Cox proportional survival analysis models. Results: Among a total of 77 568 women participants, 53%, 12.3%, and 10.3% had normal GCT results of <120, 120–129, and 130–139 mg/dL, respectively. During the study period of 6.07 ± 4.35 years, 13 151 (17.0%) cases of metabolic morbidities were documented. High-normal GCT results of 120–129 and 130–139 mg/dL were significantly associated with increased risk for future metabolic morbidity compared with <120 mg/dL (adjusted hazard ratio [aHR] 1.15, 95% confidence interval [CI] 1.08–1.22 and aHR 1.32, 95% CI 1.24–1.41, respectively). Conclusion: Although GCT is only recommended as a screening tool for gestational diabetes mellitus, high results, even within the normal range, may point to maternal increased risk for future metabolic morbidity.