Association between false positive glucose challenge test results and large-for-gestational-age infants: a retrospective cohort study

OBJECTIVES: There is no consensus regarding a possible relation between false positive glucose challenge test (GCT) results and large-for-gestational-age (LGA) infants. This study aimed to clarify the association between false positive GCT results and LGA, after adjusting for potential confounding factors, using a large clinical dataset. DESIGN: Retrospective cohort study. SETTING: National Hospital Organisation Kofu National Hospital, which is a community hospital, between January 2012 and August 2019. PARTICIPANTS: Japanese women who underwent GCT between 24 and 28 weeks of gestation at the hospital were included. After excluding those with gestational diabetes mellitus, diabetes in pregnancy and multiple pregnancies, subjects were divided into a false positive GCT group (≥140 mg/dL) and a GCT negative group (<140 mg/dL). METHODS: Obstetric records of patients were examined. The χ(2)-test and multivariable logistic regression analysis were used to investigate the association between false positive GCT results and LGA. PRIMARY AND SECONDARY OUTCOME MEASURES: Incidence of LGA and the association between false positive GCT results and LGA. RESULTS: The mean subject age was 31.4±5.5 years, with 43.3% nulliparity (n=974) and 2160 (96.1%) term deliveries. The incidence of LGA was 9.4% (211/2248) and 11.4% (257/2248) of the women had false positive GCT results. False positive GCT results were significantly associated with an increased risk of LGA (OR, 1.51; 95% CI, 1.02 to 2.23), after controlling for maternal age, prepregnancy maternal weight, maternal weight gain during pregnancy and parity. CONCLUSIONS: It appears that there is a significant association between false positive GCT results and LGA. Additional research is required to confirm these results and to investigate appropriate interventions for women with abnormal screens for gestational diabetes mellitus.