for many years , gestational diabetes mellitus ( gdm ) has been defined as  any degree of glucose intolerance first recognized during pregnancy  . recently , this definition has been redefined by the american diabetes association ( ada ) as  hyperglycemia diagnosed in the second or third trimester of pregnancy that is not clearly overt diabetes  . according to the international association of the diabetes and pregnancy study groups ( iadpsg ) criteria , the incidence of gdm in china is approximately 17.5% , which is consistent with the epidemic increase in diabetes worldwide . hyperglycemia in pregnancy is independently associated with adverse outcomes for the mother , fetus , and neonate , both in the short- and long - term . the hyperglycemia and adverse pregnancy outcome study demonstrated that the risk of adverse pregnancy outcomes continuously increased as a function of maternal glycemia at 2428 weeks of gestation , even with glucose values previously considered normal . however , the precise relationships between different oral glucose tolerance test ( ogtt ) characteristics and adverse pregnancy outcomes among gdm patients remain ambiguous . it is unclear whether one , two , or three abnormal glucose values on the ogtt represent a higher risk profile for complications . in addition , it is unclear whether fasting or postload glucose values are more closely related to adverse perinatal outcomes and whether they represent different or specific risks . understanding these relationships can facilitate the development of appropriate management strategies for gdm patients with different models of ogtt . therefore , the aim of the current analysis was to estimate how different ogtt characteristics influenced pregnancy outcomes and to determine which ogtt parameter was best correlated with specific adverse pregnancy outcomes . the study was approved by the ethics committee of peking university first hospital ( no . all participants provided written informed consent , and the ethics committee approved the consent procedure . we conducted a retrospective cohort analysis of data from the  systemic random sampling survey on the prevalence of gestational diabetes mellitus in beijing ( gdm prevalence survey [ gps ] )  . in this survey , 15 beijing hospitals were chosen using systemic cluster sampling , and random seed and sampling intervals were determined and sorted by the number of deliveries in 2012 . pregnant women who delivered from june 20 , 2013 to november 30 , 2013 were screened . the eligibility criteria include all women delivering from june 20 , 2013 to november 30 , 2013 who were carrying a singleton fetus and had performed a 75 g ogtt between 24 and 28 weeks of gestation . the exclusion criteria were women who had delivered before 28 weeks of gestation and those with either known prepregnancy diabetes mellitus or overt diabetes diagnosed during pregnancy . the participating pregnant women were tested for fasting plasma glucose ( fpg ) during their first prenatal visit using venous blood samples collected after at least 8 h of fasting . mmol / l were considered to have overt diabetes and were excluded from the study . women were considered to have gdm if any one of the following ogtt values was met or exceeded : fasting 5.10 glucose values above 7.0 mmol / l or 11.1 mmol / l at fasting and 2 h postglucose load , respectively , were considered to indicate overt diabetes . small for gestational age ( sga ) was defined as a birth weight under the 10 percentile , while large for gestational age ( lga ) was defined as a birth weight above the 90 percentile based on gender and gestational age . macrosomia was defined as a birth weight of more than 4000 g. preterm birth was defined as a delivery at gestational age < 37 weeks and 28 weeks . neonatal hypoglycemia was defined as glucose values < 35 mg / dl by heel stick within 2 h of birth and before the first nonbreastfeeding . hyperinsulinemia was defined as c - peptide levels from cord blood > 95 percentile ( > 1.77 ng / ml ) . stillbirth was defined as an absence of signs of life at or after birth , and neonatal death was defined as death of a live born neonate during the first 7 days after birth . patients diagnosed with gdm were divided into three groups : group i , group ii , and group iii , which were divided according to the number of pathological values on the ogtt and consisted of women with one , two , and three pathological glucose values , respectively . further , subgrouping was performed according to ogtt values : patients in subgroups if , i1 , and i2 were diagnosed with gdm according to a single abnormal value for fasting hyperglycemia , 1 h , and 2 h hyperglycemia , respectively [ table 1 ] . grouping strategies for gdm patients based on 75 g oral glucose tolerance test group i : gdm patients with one abnormal value on the ogtt ; group ii : gdm diagnosed by two abnormal values ; group iii : gdm patients with three abnormal values on the ogtt . : elevated glucose values that meet or exceed the gdm diagnostic criteria ; ( f ) : fasting 5.10 mmol / l ; ( 1 ) : 1 h 10.0 mmol / l ; ( 2 ) : 2 h 8.5 mmol / l ;  : normal glucose value . comparisons were made between groups and subgroups regarding the following adverse pregnancy outcomes : cesarean delivery rate , macrosomia , lga , sga , and preterm birth . in addition , neonatal complications were studied and included any of the following : hypoglycemia , hyperbilirubinemia , hyperinsulinemia , admission to the neonatal intensive care unit , stillbirth , and neonatal death . statistical analysis was conducted with spss version 20.0 ( ibm , chicago , il , usa ) software . categorical variables such as cesarean section , macrosomia , lga , preterm birth , and neonatal complications were reported as percentages . logistic regression was used in the multivariable analysis to identify the associations between fasting , 1 h , and 2 h hyperglycemia and adverse outcomes . data were adjusted for gestational age at delivery , maternal age and maternal body mass index at enrollment , and odds ratios ( ors ) with 95% confidence intervals ( cis ) were computed relative to a control group of women without gdm . the study was approved by the ethics committee of peking university first hospital ( no . all participants provided written informed consent , and the ethics committee approved the consent procedure . we conducted a retrospective cohort analysis of data from the  systemic random sampling survey on the prevalence of gestational diabetes mellitus in beijing ( gdm prevalence survey [ gps ] )  . in this survey , 15 beijing hospitals were chosen using systemic cluster sampling , and random seed and sampling intervals were determined and sorted by the number of deliveries in 2012 . pregnant women who delivered from june 20 , 2013 to november 30 , 2013 were screened . the eligibility criteria include all women delivering from june 20 , 2013 to november 30 , 2013 who were carrying a singleton fetus and had performed a 75 g ogtt between 24 and 28 weeks of gestation . the exclusion criteria were women who had delivered before 28 weeks of gestation and those with either known prepregnancy diabetes mellitus or overt diabetes diagnosed during pregnancy . the participating pregnant women were tested for fasting plasma glucose ( fpg ) during their first prenatal visit using venous blood samples collected after at least 8 h of fasting . mmol / l were considered to have overt diabetes and were excluded from the study . after 24 weeks of gestation , women received a 75 g ogtt . women were considered to have gdm if any one of the following ogtt values was met or exceeded : fasting 5.10 glucose values above 7.0 mmol / l or 11.1 mmol / l at fasting and 2 h postglucose load , respectively , were considered to indicate overt diabetes . small for gestational age ( sga ) was defined as a birth weight under the 10 percentile , while large for gestational age ( lga ) was defined as a birth weight above the 90 percentile based on gender and gestational age . macrosomia was defined as a birth weight of more than 4000 g. preterm birth was defined as a delivery at gestational age < 37 weeks and 28 weeks . neonatal hypoglycemia was defined as glucose values < 35 mg / dl by heel stick within 2 h of birth and before the first nonbreastfeeding . hyperinsulinemia was defined as c - peptide levels from cord blood > 95 percentile ( > 1.77 ng / ml ) . stillbirth was defined as an absence of signs of life at or after birth , and neonatal death was defined as death of a live born neonate during the first 7 days after birth . patients diagnosed with gdm were divided into three groups : group i , group ii , and group iii , which were divided according to the number of pathological values on the ogtt and consisted of women with one , two , and three pathological glucose values , respectively . further , subgrouping was performed according to ogtt values : patients in subgroups if , i1 , and i2 were diagnosed with gdm according to a single abnormal value for fasting hyperglycemia , 1 h , and 2 h hyperglycemia , respectively [ table 1 ] . grouping strategies for gdm patients based on 75 g oral glucose tolerance test group i : gdm patients with one abnormal value on the ogtt ; group ii : gdm diagnosed by two abnormal values ; group iii : gdm patients with three abnormal values on the ogtt . : elevated glucose values that meet or exceed the gdm diagnostic criteria ; ( f ) : fasting 5.10 mmol / l ; ( 1 ) : 1 h 10.0 mmol / l ; ( 2 ) : 2 h 8.5 mmol / l ;  : normal glucose value . comparisons were made between groups and subgroups regarding the following adverse pregnancy outcomes : cesarean delivery rate , macrosomia , lga , sga , and preterm birth . in addition , neonatal complications were studied and included any of the following : hypoglycemia , hyperbilirubinemia , hyperinsulinemia , admission to the neonatal intensive care unit , stillbirth , and neonatal death . statistical analysis was conducted with spss version 20.0 ( ibm , chicago , il , usa ) software . categorical variables such as cesarean section , macrosomia , lga , preterm birth , and neonatal complications were reported as percentages . logistic regression was used in the multivariable analysis to identify the associations between fasting , 1 h , and 2 h hyperglycemia and adverse outcomes . data were adjusted for gestational age at delivery , maternal age and maternal body mass index at enrollment , and odds ratios ( ors ) with 95% confidence intervals ( cis ) were computed relative to a control group of women without gdm . in total , 15,194 pregnant women were included in the initial sample cohort . after excluding 253 women with a multiple pregnancy and 200 women with pregestational or overt diabetes , the study group consisted of 2927 ( 19.86% ) women with gdm and a control group of 11,814 ( 80.14% ) pregnant women with a normal ogtt . compared to non - gdm women , gdm patients had a higher risk of cesarean delivery , macrosomia , lga infants , preterm birth , and neonatal complication , but a lower risk of sga infants . prevalence of adverse pregnancy outcomes in patients with and without gdm data were presented as n ( % ) . gdm : gestational diabetes mellitus ; lga : large for gestational age ; sga : small for gestational age ; ci : confidence interval ; or : odds ratio . gdm patients were also divided into three groups : group i , group ii , and group iii which consisted of patients with one , two , and three abnormal glucose values , respectively [ table 3 ] . more cesarean deliveries , preterm births , and neonatal complications were observed in group ii than those in group i ( p < 0.001 ) . the prevalence of cesarean delivery , macrosomia , lga , preterm birth , and neonatal complications was higher in group iii than those in group ii ( p < 0.001 ) [ table 3 ] . the ors , relative to the non - gdm group , were presented in supplementary table 1 . as the number of abnormal glucose parameters increased , the associations with adverse pregnancy outcomes became stronger , with the strongest association in group iii . adverse pregnancy outcomes in different gdm groups data are presented as n ( % ) . * p<0.05 versus non - gdm group ; p<0.001 versus group i ; p<0.01 versus group ii . group i : gdm patients with one abnormal value on the ogtt ; group ii : gdm diagnosed by two abnormal values ; group iii : gdm patients with three abnormal values on the ogtt . gdm : gestational diabetes mellitus ; lga : large for gestational age ; sga : small for gestational age ; ogtt : oral glucose tolerance test . ors of adverse pregnancy outcomes in different gdm groups data are presented as or ( 95% ci ) . group i : gdm patients with one abnormal value at the ogtt ; group ii : gdm diagnosed by two abnormal values ; group iii : gdm patients with three abnormal values at the ogtt . ci : confidence interval ; ors : odds ratios ; gdm : gestational diabetes mellitus ; lga : large for gestational age ; sga : small for gestational age ; ogtt : oral glucose tolerance test . gdm patients in each group were further subclassified , and the rates of adverse outcomes by ogtt subgroup were shown in table 4 . in subgroup if , in which a single abnormal fasting ogtt value served as the gdm diagnostic criteria , significantly more macrosomia and lga were detected than in subgroups i1 and i2 , in which 1 h or 2 h glucose values were abnormal , respectively . in group ii , which had two abnormal ogtt values , subgroups iif+1 and iif+2 , which had abnormal fasting glucose and one of the postload values over the threshold , demonstrated significantly higher rates of macrosomia and lga than in gdm patients with both postload glucose values but a normal fasting glucose ( subgroup ii1 + 2 ) . adverse pregnancy outcomes in different ogtt subgroups data are presented as n ( % ) . * p<0.05 versus non - gdm group ; p<0.001 versus group if ; p<0.001 versus group i1 ; p<0.001 , versus group ii1 + 2 ; p<0.001 versus group iif+1 . group i : gdm patients with one abnormal value on the ogtt ; subgroups if , i1 , and i2 were diagnosed as gdm according to a single abnormal value for fasting hyperglycemia , 1-h and 2-h hyperglycemia , respectively ; group ii : gdm diagnosed by two abnormal values ; group iii : gdm patients with three abnormal values on the ogtt . gdm : gestational diabetes mellitus ; lga : large for gestational age ; sga : small for gestational age ; ogtt : oral glucose tolerance test . fasting hyperglycemia had the strongest association with macrosomia ( or : 1.84 , 95% ci : 1.392.42 , p < 0.001 ) , lga ( or : 1.70 , 95% ci : 1.292.25 , p < 0.001 ) , and cesarean delivery ( or : 1.33 , 95% ci : 1.151.55 , p < 0.001 ) . ors of adverse pregnancy outcomes for hyperglycemia ( n = 14,741 ) lga : large for gestational age ; sga : small for gestational age ; ci : confidence interval ; ors : odds ratios ; ogtt : oral glucose tolerance test . gdm mothers with abnormal 2 h ogtt were more likely to have preterm birth [ table 4 ] . for gdm patients with one abnormal glucose result , subgroup i2 , which included patients with abnormal 2 h ogtt , we found higher rates of preterm labor than in subgroups if and i1 , which included gdm with normal 2 h ogtt . a similar distribution was observed in group ii , which had 8.4% premature infants in subgroup iif+2 ; 7.3% in subgroup ii1 + 2 ; and 6.2% in subgroup iif+1 . that is , 2 h hyperglycemia seemed to be associated with more preterm labor in gdm mothers . the or for the association was 1.50 ( 95% ci : 1.392.42 , p = 0.009 ) [ table 5 ] . mmol / l in the ogtt had less macrosomia , lga , and cesarean delivery , whether in group i or group ii table 4 . moreover , it is worth noting that although gdm diagnosis did not increase the rate of sga infants according to our data , some differences were observed in the sga distribution of different ogtt models . after comparing the prevalence of sga , subgroup i2 which included gdm patients with elevated 2 h ogtt as the diagnostic criteria had the highest rate of sga ( 5.8% ) . patients with abnormal 2 h ogtt exhibited a nonsignificant trend for having more sga infants than patients with normal 2 h ogtt . in subgroups iif+2 and ii1 + 2 , in which abnormal 2 h ogtt was one of the diagnostic thresholds , there were more sga infants than in subgroup iif+1 , which had normal 2 h ogtt , with rates of 3.1% and 3.2% compared to 2.5% , respectively ( p = 0.002 ) [ table 4 ] . based on this finding , it seemed that there might have been an association between 2 h ogtt glucose and fetal growth restriction in gdm patients , with an or of 1.28 ( 95% ci : 0.871.88 , p = 0.210 ) for sga and 0.74 ( 95% ci : 0.560.97 , p = 0.028 ) for macrosomia [ table 5 ] . fasting hyperglycemia was associated with perinatal outcomes , including macrosomia , lga , and cesarean delivery . the fasting glucoses on the ogtt were further stratified into 0.5-unit increments [ table 6 ] . among pregnant women , the group with a fasting glucose level of 4.60 to 6.59 mmol / l was associated with macrosomia , lga , and cesarean delivery ( p < 0.001 ) when compared against the group with fasting glucose < 4.1 mmol / l . the ors of macrosomia ( up to 5.36 folds ) , lga ( up to 5.74 folds ) , and cesarean delivery ( up to 2.94 folds ) were higher in subgroups with higher fasting glucose levels . however , the subgroup with values in the 6.60 to 6.99 mmol / l range did not show statistical significance for macrosomia , lga , or cesarean delivery . ors of pregnancy outcomes according to different ranges of fasting glucose in the 75 g ogtt lga : large for gestational age ; ci : confidence interval ; ors : odds ratios ; ogtt : oral glucose tolerance test . table 2 illustrates the relationship of maternal gdm with adverse pregnancy outcomes . compared to non - gdm women , gdm patients had a higher risk of cesarean delivery , macrosomia , lga infants , preterm birth , and neonatal complication , but a lower risk of sga infants . prevalence of adverse pregnancy outcomes in patients with and without gdm data were presented as n ( % ) . gdm : gestational diabetes mellitus ; lga : large for gestational age ; sga : small for gestational age ; ci : confidence interval ; or : odds ratio . gdm patients were also divided into three groups : group i , group ii , and group iii which consisted of patients with one , two , and three abnormal glucose values , respectively [ table 3 ] . more cesarean deliveries , preterm births , and neonatal complications were observed in group ii than those in group i ( p < 0.001 ) . the prevalence of cesarean delivery , macrosomia , lga , preterm birth , and neonatal complications was higher in group iii than those in group ii ( p < 0.001 ) [ table 3 ] . the ors , relative to the non - gdm group , were presented in supplementary table 1 . as the number of abnormal glucose parameters increased , the associations with adverse pregnancy outcomes became stronger , with the strongest association in group iii . adverse pregnancy outcomes in different gdm groups data are presented as n ( % ) . * p<0.05 versus non - gdm group ; p<0.001 versus group i ; p<0.01 versus group ii . group i : gdm patients with one abnormal value on the ogtt ; group ii : gdm diagnosed by two abnormal values ; group iii : gdm patients with three abnormal values on the ogtt . gdm : gestational diabetes mellitus ; lga : large for gestational age ; sga : small for gestational age ; ogtt : oral glucose tolerance test . ors of adverse pregnancy outcomes in different gdm groups data are presented as or ( 95% ci ) . group i : gdm patients with one abnormal value at the ogtt ; group ii : gdm diagnosed by two abnormal values ; group iii : gdm patients with three abnormal values at the ogtt . ci : confidence interval ; ors : odds ratios ; gdm : gestational diabetes mellitus ; lga : large for gestational age ; sga : small for gestational age ; ogtt : oral glucose tolerance test . gdm patients in each group were further subclassified , and the rates of adverse outcomes by ogtt subgroup were shown in table 4 . in subgroup if , in which a single abnormal fasting ogtt value served as the gdm diagnostic criteria , significantly more macrosomia and lga were detected than in subgroups i1 and i2 , in which 1 h or 2 h glucose values were abnormal , respectively . in group ii , which had two abnormal ogtt values , subgroups iif+1 and iif+2 , which had abnormal fasting glucose and one of the postload values over the threshold , demonstrated significantly higher rates of macrosomia and lga than in gdm patients with both postload glucose values but a normal fasting glucose ( subgroup ii1 + 2 ) . adverse pregnancy outcomes in different ogtt subgroups data are presented as n ( % ) . * p<0.05 versus non - gdm group ; p<0.001 versus group if ; p<0.001 versus group i1 ; p<0.001 , versus group ii1 + 2 ; p<0.001 versus group iif+1 . group i : gdm patients with one abnormal value on the ogtt ; subgroups if , i1 , and i2 were diagnosed as gdm according to a single abnormal value for fasting hyperglycemia , 1-h and 2-h hyperglycemia , respectively ; group ii : gdm diagnosed by two abnormal values ; group iii : gdm patients with three abnormal values on the ogtt . gdm : gestational diabetes mellitus ; lga : large for gestational age ; sga : small for gestational age ; ogtt : oral glucose tolerance test . fasting hyperglycemia had the strongest association with macrosomia ( or : 1.84 , 95% ci : 1.392.42 , p < 0.001 ) , lga ( or : 1.70 , 95% ci : 1.292.25 , p < 0.001 ) , and cesarean delivery ( or : 1.33 , 95% ci : 1.151.55 , p < 0.001 ) . ors of adverse pregnancy outcomes for hyperglycemia ( n = 14,741 ) lga : large for gestational age ; sga : small for gestational age ; ci : confidence interval ; ors : odds ratios ; ogtt : oral glucose tolerance test . gdm mothers with abnormal 2 h ogtt were more likely to have preterm birth [ table 4 ] . for gdm patients with one abnormal glucose result , subgroup i2 , which included patients with abnormal 2 h ogtt , we found higher rates of preterm labor than in subgroups if and i1 , which included gdm with normal 2 h ogtt . a similar distribution was observed in group ii , which had 8.4% premature infants in subgroup iif+2 ; 7.3% in subgroup ii1 + 2 ; and 6.2% in subgroup iif+1 . that is , 2 h hyperglycemia seemed to be associated with more preterm labor in gdm mothers . the or for the association was 1.50 ( 95% ci : 1.392.42 , p = 0.009 ) [ table 5 ] . mmol / l in the ogtt had less macrosomia , lga , and cesarean delivery , whether in group i or group ii table 4 . moreover , it is worth noting that although gdm diagnosis did not increase the rate of sga infants according to our data , some differences were observed in the sga distribution of different ogtt models . after comparing the prevalence of sga , subgroup i2 which included gdm patients with elevated 2 h ogtt as the diagnostic criteria had the highest rate of sga ( 5.8% ) . patients with abnormal 2 h ogtt exhibited a nonsignificant trend for having more sga infants than patients with normal 2 h ogtt . in subgroups iif+2 and ii1 + 2 , in which abnormal 2 h ogtt was one of the diagnostic thresholds , there were more sga infants than in subgroup iif+1 , which had normal 2 h ogtt , with rates of 3.1% and 3.2% compared to 2.5% , respectively ( p = 0.002 ) [ table 4 ] . based on this finding , it seemed that there might have been an association between 2 h ogtt glucose and fetal growth restriction in gdm patients , with an or of 1.28 ( 95% ci : 0.871.88 , p = 0.210 ) for sga and 0.74 ( 95% ci : 0.560.97 , p = 0.028 ) for macrosomia [ table 5 ] . fasting hyperglycemia was associated with perinatal outcomes , including macrosomia , lga , and cesarean delivery . the fasting glucoses on the ogtt were further stratified into 0.5-unit increments [ table 6 ] . among pregnant women , the group with a fasting glucose level of 4.60 to 6.59 mmol / l was associated with macrosomia , lga , and cesarean delivery ( p < 0.001 ) when compared against the group with fasting glucose < 4.1 mmol / l . the ors of macrosomia ( up to 5.36 folds ) , lga ( up to 5.74 folds ) , and cesarean delivery ( up to 2.94 folds ) were higher in subgroups with higher fasting glucose levels . however , the subgroup with values in the 6.60 to 6.99 mmol / l range did not show statistical significance for macrosomia , lga , or cesarean delivery . ors of pregnancy outcomes according to different ranges of fasting glucose in the 75 g ogtt lga : large for gestational age ; ci : confidence interval ; ors : odds ratios ; ogtt : oral glucose tolerance test . in 2011 , based on the iadpsg guidelines , the ada recommended for the first time that all pregnant women not known to have prior diabetes undergo a 75-g ogtt at 2428 weeks of gestation . the national health and family planning commission of china adopted testing and diagnostic criteria based on the iadpsg guidelines . through these guidelines , single abnormal blood glucose levels can be diagnosed , which means more pregnant women are included as having gdm . moreover , these gdm patients have different hyperglycemia characteristics , which may lead to different pregnant outcomes . first , gdm results in further adverse maternal , fetal , and neonatal outcomes , including cesarean deliveries , macrosomia , lga , preterm birth , and neonatal complications . moreover , in addition to the plasma glucose levels in ogtt , the number of abnormal ogtt parameters also identified different degrees of maternal hyperglycemia and maternal / fetal risk . we found consistent trends between the number of abnormal glucose parameters and frequencies of adverse outcomes , such as cesarean delivery , premature delivery , and neonatal complications . increasing numbers of abnormal parameters in the ogtt were associated with higher odds of the incidence of adverse perianal outcomes . compared with one hyperglycemic value , patients with two or more elevated glucose values may have a more severe disruption in glucose metabolic balance and insulin sensitivity . this finding should be taken into account during pregnancy follow - up and management of hyperglycemia with stricter glucose control , including regulation of diet and exercise and administration of insulin , to attain satisfactory glycemic control . not all abnormal glucose ogtt values resulted in the same adverse outcomes or in the same risk of a specific adverse outcome . the metabolic physiology of pregnancy is characterized by fasting hypoglycemia due to insulin - independent glucose uptake by the placenta , postprandial hyperglycemia , and carbohydrate intolerance as a result of diabetogenic placental hormones . in addition , insulin resistance increases exponentially during the second trimester and levels off toward the end of the third trimester . for gdm patients , fasting hyperglycemia may mean that glucose metabolic abnormalities are more prone to causing adverse perinatal outcomes . however , the associations between fasting hyperglycemia and adverse perinatal outcomes seem more obvious in regard to fetal growth , as gdm is characterized by increased risk of macrosomia , without a risk threshold . previous studies have suggested that fasting glucose levels are associated with neonatal adiposity including body fat percentage and increased skinfold thickness in neonates born to women with both diet- and insulin - treated gestational diabetes . consistent with those reports , our data also showed positive associations of fasting hyperglycemia with macrosomia and lga . moreover , the association was stronger with increases in fasting glucose , although the highest risk was not observed in the 6.606.99 mmol / l group , likely due to the limited samples available for the analysis . moreover , it was worth noting that these results were in contrast to those reported in studies by de veciana et al . and combs et al . , who described a consistent association between postprandial glucose values and birth weight , frequency of lga , and macrosomia . more gdm patients diagnosed by fasting ogtt 5.1 mmol / l received a cesarean section . however , it should be considered that the diagnosis of gdm itself shifts obstetric practice toward operative delivery because of its association with macrosomia . meanwhile , some confounders , such as previous gdm , previous macrosomia , and social psychological factors , may also influence clinical decisions regarding the mode of delivery . in addition to this increase in operative delivery , macrosomic infants are at risk for a variety of perinatal complications , including higher rates of shoulder dystocia and birth trauma . moreover , longitudinal population studies have documented that macrosomia and lga confer high risks for infants long - term health . fetal overgrowth and increased neonatal fat mass have been linked to the development of obesity and metabolic syndrome in childhood and adolescence . given the close relationship of fasting glucose with macrosomia and lga , the normalization of fasting glucose in gdm has immediate benefits and could potentially improve long - term health outcomes for mothers and neonates . offspring of diabetic mothers may be macrosomic , sga , or of normal birth weight , depending on the severity of the mother 's diabetes , presence or absence of complications , and the degree of diabetic control . in poorly controlled diabetes without severe complications , improved glycemic control would normalize fetal growth , while severe diabetes or overly strict control may often result in sga offspring . this lack of association might be because our population included gdm patients who had received interventions such as diet , exercise , and insulin treatment after diagnosis , and these interventions might have resulted in good control without deterioration to severe uncontrolled diabetes . however , it is worth noting that gdm patients with abnormal 2 h ogtt values had a trend toward more sga infants than gdm women with normal 2 h ogtt . a clear difference was observed in gdm patients with one abnormal glucose parameter ; when combined with elevated 0 h or 1 h glucose , the effect of 2 h hyperglycemia on sga seemed to be attenuated . as sga is a risk factor for a variety of diseases including hypertension , cardiovascular disease , and diabetes , these results suggest that more attention is needed for sga prevention in gdm mothers , especially if they show an abnormal 2 h ogtt value . furthermore , it appeared to be more closely related to elevated postload glucose than abnormal fasting values , with the highest risks of preterm delivery observed among women with normal fasting and two elevated postload glucose values . our data demonstrate a trend toward more preterm infants in mothers with hyperglycemia in the 2 h ogtt . further research efforts should determine the precise influence of 2 h ogtt values on premature birth . first , it was worth noting that the patients investigated in this study accepted some form of intervention , including diet , exercise , and insulin treatment . it was reasonable to speculate that , if not treated , gdm mothers and their offspring would have had worse adverse outcomes and that the links between different parameters of ogtt and adverse perinatal outcomes would thus be more severe . in addition , participants nutritional status could affect fetal growth and other perinatal outcomes , but we did not have data on these variables . in conclusion , our study indicated the following : first , as the number of hyperglycemic values in the ogtt increased , there was a significant increase in cesarean delivery , preterm birth , lga infants , macrosomia , and neonatal complications . in addition , fasting hyperglycemia was associated with more macrosomia , lga , and cesarean delivery , and the association was stronger for higher glucose values . finally , hyperglycemia according to the 2 h ogtt was associated with a greater possibility of preterm birth and sga . supplementary information is linked to the online version of the paper on the chinese medical journal website .
background : hyperglycemia is associated with adverse pregnancy outcomes . however , 
 the relationships between them remain ambiguous . 
 this study aimed to analyze the effect of different oral glucose tolerance test ( ogtt ) results on adverse perinatal outcomes.methods:this retrospective cohort study included data from 15 hospitals in beijing from june 20 , 2013 to november 30 , 2013 . 
 women with gestational diabetes mellitus ( gdm ) were categorized according to the number and distribution of abnormal ogtt values , and the characteristics of adverse pregnancy outcomes were evaluated . chi - square test and logistic regression analysis were used to determine the associations.results:in total , 14,741 pregnant women were included in the study population , 2927 ( 19.86% ) of whom had gdm . 
 as the number of hyperglycemic values in the ogtt increased , the risk of cesarean delivery , preterm births , large - for - gestational age ( lga ) , macrosomia , and neonatal complications significantly increased . 
 fasting hyperglycemia had clear associations with macrosomia ( odds ratios [ ors]:1.84 , 95% confidence intervals [ cis ] : 1.392.42 , p < 0.001 ) , lga ( or : 1.70 , 95% ci : 1.292.25 , p < 0.001 ) , and cesarean delivery ( or : 1.33 , 95% ci : 1.151.55 , p < 0.001 ) . the associations were stronger as fasting glucose increased . 
 gdm diagnosed by hyperglycemia at ogtt-2 h was more likely to lead to preterm birth ( or : 1.50 , 95% ci : 1.112.03 , p < 0.01).conclusions : various characteristics of ogtts are associated with different adverse outcomes 
 . a careful reconsideration of gdm with hierarchical and individualized management according to ogtt characteristics is needed .