Value of fasting plasma glucose in oral glucose tolerance test on gestational diabetes mellitus diagnosis

Objective To investigate the value of fasting plasma glucose (FPG) in 75 g oral glucose tolerance test (OGTT) on the diagnosis of gestational diabetes mellitus (GDM).Methods Data of 6516 pregnant women who accepted prenatal cares from Beijing Obstetrics and Gynecology Hospital,Capital Medical University between Jan.2010 and Dec.2010 were collected.All patients had normal FPG at first trimester,and accepted 75 g OGTT after abnormal 50 g glucose challenge test (≥7.8 mmol/L).According to the result of OGTT,they were divided into 12 groups,and Chisquare test was used to analyze the role of FPG of OGTT in GDM diagnosis.Results According to the International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria,15.0％ (980/ 6516) of this group of pregnant women was diagnosed with GDM by FPG (≥5.1 mmol/L) of OGTT in this study.Then,the rest 5536 pregnant women with normal FPG of OGTT were divided into 12 groups according to FPG level (FPG level interval 0.1 mmol/L).As FPG level rose,the incidence of GDM also rose (X2 =282.175,P =0.000).Similar results also appeared when the interval was 0.2 mmol/L and the FPG level was between 4.0 and 4.8 mmol/L (X2 =274.364,P=0.000).When FPG level was lower than 4.2 mmol/L(22.1％,1226/5536),the incidence of GDM diagnosed by OGTT was 3.6％ (44/1226).And when FPG level of OGTT was higher than 4.8 mmol/L,the incidence of GDM was 26.2％ (298/1138).Conclusions FPG screening is recommended between 24 and 28 gestational weeks before OGTT,and GDM low-risk women whose FPG ≤4.2 mmol/L do not need OGTT. Key words: Diabetes, gestational; Glucose tolerance test; Blood glucose