Background The concentration of serum fructosamine is correlated with plasma glucose level. The aim of this study was to determine whether the level of serum fructosamine can be diagnostic for abnormal glucose tolerance in pregnant women. Methods Serum samples were collected from 161 pregnant women between November 2004 and April 2005. The women were divided into three groups according to the gestational age (16-20 weeks group, 56 patients; 28 -34 weeks group, 72; and 37-41 weeks group, 33). Each group was subdivided into normal and abnormal glucose tolerance subgroups. The levels of serum fructosamine were measured. Differences among the groups were assessed by ANOVA and Student-Newman-Keuls test. Correlations between the level of fructosamine and other variables including the results of glucose challenge test (GCT), oral glucose tolerance test (OGTT), and glycosylated hemoglobin (HbA1c) test, and infant’s birth weight were analyzed by Pearson correlation. Results The level of serum fructosamine decreased with gestational age [(223.25±48.90) μmol/L, (98.44±29.57) μmol/L, and (53.99±29.94) μmol/L, respectively. P<0.05]. It was higher in women with abnormal glucose tolerance than that in women with normal glucose tolerance, however, the difference reached statistical significance only in the 28-34 weeks group (P<0.05). In this group, the level of serum fructosamine correlated positively with the GCT result (r=0.28, P<0.05). No correlation was found between fructosamine level and OGTT result, HbA1c level, or neonatal weight. Conclusions Fructosamine can be used to monitor the glucose level of pregnant women with abnormal glucose tolerance, and to identify the patients at high risk of abnormal glucose tolerance, but can not be used to predict gestational diabetes mellitus (GDM) in early stage of pregnancy. Background The concentration of serum fructosamine is correlated with plasma glucose level. The aim of this study was to be determination whether the level of serum fructosamine can be diagnostic for abnormal glucose tolerance in pregnant women. Methods Serum samples were collected from 161 pregnant women between November 2004 and April 2005. The women were divided into three groups according to the gestational age (16-20 weeks group, 56 patients; 28-34 weeks group, 72; and 37-41 weeks group, 33). Each group was subdivided into normal and abnormal glucose tolerance subgroups. The levels of the serum fructosamine were measured by ANOVA and Student-Newman-Keuls test. Correlations between the level of fructosamine and other variables including the results of glucose challenge test (GCT), oral glucose tolerance test (OGTT), and glycosylated hemoglobin (HbA1c) test, and infant’s birth weight were analyzed by Pearson correlation. Results The level of serum fructosamine decreased with gestational age [(223.25 ± 48.90) μmol / L, (98.44 ± 29.57) μmol / L, and (53.99 ± 29.94) μmol / L, respectively, P <0.05]. It was higher in women with abnormal glucose tolerance than that in women with normal glucose tolerance, however, the difference reached statistical significance only in the 28-34 weeks group (P <0.05). In this group, the level of serum fructosamine positively with the GCT result (r = 0.28, P <0.05). No correlation was found between fructosamine level and OGTT result, HbA1c level, or neonatal weight. Conclusions Fructosamine can be used to monitor the glucose level of pregnant women with abnormal glucose tolerance, and to identify the patients at high risk of abnormal glucose tolerance, but can not be used to predict gestational diabetes mellitus (GDM) in early stage of pregnancy.