Association between Abnormal Glucose Challenge Test and Pregnancy Outcomes

Background and Objective: Glucose Challenge Test (GCT) is done for pregnant women during the week ۲۴-۲۸ of gestation to screen gestational diabetes. In patients with abnormal GCT, a glucose tolerance test (GTT) is performed, and if GTT is impaired, the patient is diagnosed with gestational diabetes. There is some evidence suggesting that abnormal GCT alone is associated with adverse pregnancy outcomes. The aim of this study was to determine the pregnancy outcomes in patients with abnormal GCTs but normal GTT scores. Materials and Methods: In this cohort study, GCT was carried out on ۱۹۰ pregnant women during the ۲۴th to ۲۸th weeks of gestation. Ninety-five pregnant women with abnormal GCT and normal GTT (study group) and ۹۵ cases with normal GCT (control group) scores entered the study and were compared regarding adverse pregnancy outcomes. Results: The average birth weight in the study and control groups were۳۳۹۷±۵۲۴gr and ۳۲۳۴±۳۸۴ gr respectively (P=۰.۰۱۵). Fourteen neonates (۱۴.۷%) in the study group and ۴(۴.۲%) in the control group had macrosomia (P=۰.۰۱۳). Frequency of preterm labor was ۸ (۸.۴%) in the cases and ۱ (۱%) in the controls (P=۰.۰۳). Frequency of preeclampsia was ۸ (۸.۴%) in the cases and ۱ (۱%) in the controls (P=۰.۰۳). There was positive family history of diabetes mellitus in ۲۰ (۲۱%) of the cases and ۱ (۱%) in the controls (P<۰.۰۰۱). Mean BMI changes was ۵+۱.۷ in the study group and ۴.۳+۴.۳ in the controls (P<۰.۰۰۴). Conclusion: The prevalence of macrosomia, preterm labor, preeclampsia, family history of diabetes, increasing maternal BMI, and average birth weight were all higher in the pregnant women with abnormal GCT. Thus, due to the high incidence of some unfavorable outcomes, careful follow up women with abnormal GCT but normal GTT appears necessary during pregnancy.