Single Fasting Plasma Glucose Versus 75-g Oral Glucose-Tolerance Test in Prediction of Adverse Perinatal Outcomes: A Cohort Study

Abstract

Background: There remains uncertainty regarding whether a single fasting glucose measurement is sufficient to predict risk of adverse perinatal outcomes.

Methods: We included 12,594 pregnant women who underwent a 75-g oral glucose-tolerance test (OGTT) at 22-28weeks' gestation in the Born in Guangzhou Cohort Study, China. Outcomes were large for gestational age (LGA) baby, cesarean section, and spontaneous preterm birth. We calculated the area under the receiver operator characteristic curves (AUCs) to assess the capacity of OGTT glucose values to predict adverse outcomes, and compared the AUCs of different components of OGTT.

Results: 1325 women had a LGA baby (10.5%). Glucose measurements were linearly associated with LGA, with strongest associations for fasting glucose (odds ratio 1.37, 95% confidence interval 1.30-1.45). Weaker associations were observed for cesarean section and spontaneous preterm birth. Fasting glucose have a comparable discriminative power for prediction of LGA to the combination of fasting, 1h, and 2h glucose values during OGTT (AUCs, 0.611 vs. 0.614, P=0.166). The LGA risk was consistently increased in women with abnormal fasting glucose (≥5.1mmol/l), irrespective of 1h or 2h glucose levels.

Conclusions: A single fasting glucose measurement performs comparably to 75-g OGTT in predicting risk of having a LGA baby.

Keywords: Cesarean section; Fasting plasma glucose; Large for gestational age; Oral glucose-tolerance test; Spontaneous preterm birth.

Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Figures

Fig. 1

The recruitment and participation flowchart.

Fig. 2

Receiver operating characteristic curves (ROCs) of fasting, 1 h and 2 h glucose measurements for prediction of perinatal outcomes. *The AUCs for 1 h or/and 2 h glucose were significantly different from fasting glucose (P < 0.05).

Fig. 3

Prevalence of perinatal outcomes by IADPSG criteria (glucose level). ‘Case’ indicates the number of outcome cases in corresponding category of glucose levels. ‘Total’ indicates the total number of pregnant women in corresponding category of glucose levels. ‘%’ indicates the prevalence of outcomes in corresponding category of glucose levels. Non-GDM: no glucose impairment; i-IFG: isolated impaired fasting glucose if FPG ≥ 5.1 mmol/l and both 1 h glucose < 10.0 mmol/l and 2 h glucose < 8.5 mmol/l; i-IGT1: single isolated impaired 1 h glucose tolerance if 1 h glucose ≥ 10.0 mmol/l and both 2 h glucose < 8.5 mmol/l and FPG < 5.1 mmol/l; i-IGT2: single isolated impaired 2 h glucose tolerance if 2 h glucose ≥ 8.5 mmol/l and both 1 h glucose < 10.0 mmol/l and FPG < 5.1 mmol/l; i-IGT1 + 2: double-isolated impaired glucose tolerance if both 1 h glucose ≥ 10.0 mmol/l and 2 h glucose ≥ 8.5 mmol/l but FPG < 5.1 mmol/l; IFG + IGT1: combined IFG and IGT1 if FPG ≥ 5.1 mmol/l and 1 h glucose ≥ 10.0 mmol/l but 2 h glucose < 8.5 mmol/l; IFG + IGT2: combined IFG and IGT2 if FPG ≥ 5.1 mmol/l and 2 h glucose ≥ 8.5 mmol/l but 1 h glucose < 10.0 mmol/l; IFG + IGT1 + 2: combined IFG and IGT1 + 2 if FPG ≥ 5.1 mmol/l and 1 h glucose ≥ 10.0 mmol/l and 2 h ≥ 8.5 mmol/l.