Glucose challenge test: Screening threshold for gestational diabetes mellitus and associated outcomes

Objective. To examine whether women with an 1-hour 50-g glucose challenge test (GCT) for gestational diabetes mellitus (GDM) between 120 and 140 mg/dL and ≥140 mg/dL are at risk of perinatal complications.

Study design. A retrospective cohort study of women with singleton pregnancies screened for GDM between 1988 and 2001 with a 1-hour 50-g GCT. Values of GCT were stratified into four subgroups: <120, 120–129, 130–139, and ≥140 mg/dL. Perinatal outcomes were compared using the Chi-square test and multivariable logistic regression analysis.

Results. There were 13 901 women meeting the study criteria. Compared to women with a GCT of <120 mg/dL, women with a GCT of 130–139 mg/dL and ≥140 mg/dL were more likely to have preeclampsia and operative vaginal or cesarean deliveries. Neonates born to women with a GCT of 130–139 mg/dL also had higher odds of having a 5-minute Apgar score <7 (odds ratio (OR) = 1.51, 95% confidence interval (CI) 1.01–2.29), shoulder dystocia (OR = 2.02, 95% CI 1.16–2.55), birth trauma (OR = 1.47, 95% CI 1.06–2.02), and composite morbidity (OR = 1.25, 95% CI 1.03–1.51). Women with a GCT of ≥140 mg/dL had higher odds of macrosomia (OR = 1.32, 95% CI 1.13–1.54) and shoulder dystocia (OR = 1.68, 95% CI 1.11–2.55).

Conclusion. Women with GCT results of 130–139 mg/dL appear to be at increased risk for perinatal morbidity. Thus, utilizing a diagnostic test in women with a GCT above 130 mg/dL should be considered.     

Abnormal results on a second testing and risk of gestational diabetes in women with normal baseline glucose levels.

OBJECTIVE: To examine the rate of women with normal initial results to glucose tolerance tests who have abnormal results to subsequent testing, and estimate the risk of gestational diabetes mellitus (GDM) in these women. METHODS: Baseline plasma glucose levels were classified as normal if they were less than 120 mg/dL (group 1) or between 120 and 139 mg/dL (group 2) by the 50-g glucose challenge test (GCT); as abnormal if they were found abnormal by the 50-g GCT but normal by the 100-g glucose tolerance test (OGTT) (group 3); and as abnormal if 1 of the four 100-g OGTT values was abnormal (group 4). A second testing session with the 50-g GCT and 100-g OGTT was performed between the 24th and 28th weeks of pregnancy for 900 women at risk whose initial test results were normal. RESULTS: Of the 823 women with normal baseline results who completed the study, 41.4% had abnormal results to the second 50-g GCT, and gestational diabetes mellitus was diagnosed by the 100-g OGTT in 7.0% of these 823 women. Compared with group 1, the women in groups 2, 3, and 4 were at a significantly increased risk of having an abnormal result to the second 50-g GCT. They were also at a significantly increased risk for GDM. The adjusted odds ratios (ORs) were 3.0 for group 2 (95% confidence interval [CI], 1.2-7.2), 4.9 for group 3 (95% CI, 2.2-11.0), and 11.3 for group 4 (95% CI, 3.9-32.6). CONCLUSION: The risk of developing GDM significantly increased with increasing baseline plasma glucose levels by the 50-g GCT.     

Is abnormal 50-g glucose-challenge testing an independent predictor of adverse pregnancy outcome?

Objective: To determine whether an abnormal 50-g glucose-challenge test (GCT) is independently associated with adverse pregnancy outcome. Methods: A retrospective study of women with abnormal GCT (>140?mg/dL) but normal subsequent 100-g oral glucose-tolerance test (OGTT). Pregnancy outcome was compared with that of women with normal GCT (<140?mg/dL). Results: Of the 79,153 women delivered during the study period, the results of the GCT were available for 14,268. Of these, 809 (5.7%) had an abnormal GCT and normal OGTT and were eligible for the study group. An abnormal GCT was independently associated with an increased risk for macrosomia (odds ratio [OR] = 2.0, 95% CI: 1.5–2.7), large for gestational age (OR = 1.6, 95% CI: 1.3–2.0), cesarean section (OR = 1.3, 95% CI: 1.1–1.6), respiratory morbidity (OR = 1.6, 95% CI: 1.1–2.7) and neonatal hypoglycemia (OR = 1.8, 95% CI: 1.1–3.2). In contrast, an abnormal GCT was associated with decreased risk for preterm delivery at less than 37 weeks (OR = 0.7, 95% CI: 0.5–0.9) and 34 weeks (OR = 0.3, 95% CI: 0.1–0.6). The association between abnormal GCT and adverse pregnancy outcome was unrelated to the degree of GCT abnormality except for cases in which the GCT was extremely high (≥180?mg/dL). Conclusion: Women with abnormal-GCT result are at increased risk for adverse pregnancy outcome even in the presence of a normal subsequent OGTT.     

False-positive 1-hour glucose challenge test and adverse perinatal outcomes

OBJECTIVE: To determine whether a false-positive 1-hour glucose challenge test (GCT) is associated with perinatal complications. METHODS: We performed a retrospective cohort study of 1825 eligible pregnant women among a cohort of 1998 patients. Patients were screened for gestational diabetes mellitus (GDM) with the 1-hour 50-g GCT at 24-28 gestational weeks. A false-positive GCT was defined as a result greater than or equal to 135 mg/dL followed by a normal 3-hour glucose tolerance test (GTT). We compared the negative GCT and false-positive GCT cohorts for a composite perinatal outcome variable that included fetal macrosomia, antenatal death, shoulder dystocia, chorioamnionitis, preeclampsia, intensive care nursery admission, and postpartum endometritis. Secondary outcomes included cesarean delivery and each component variable of the composite. Unadjusted, stratified, and multiple logistic regression analyses were used to investigate the association between a false-positive GCT and the development of perinatal complications. RESULTS: We identified 164 patients with a false-positive GCT and 50 patients with GDM. The false-positive GCT cohort on average was older, of higher parity, had a higher body mass index, and more frequently had chronic hypertension, sickle cell trait, and elevated midtrimester human chorionic gonadotropin levels. The false-positive GCT cohort more frequently had adverse perinatal outcomes, including the composite perinatal outcome (odds ratio [OR] 5.96, 95% confidence interval[CI]1.47,24.16), macrosomia greater than 4500 g (OR 3.66, 95% CI 1.30, 10.32), antenatal death (OR 4.61, 95% CI 0.77, 27.48), shoulder dystocia (OR 2.85, 95% CI 1.25, 6.51), endometritis (OR 2.18, 95% CI 1.03, 4.63), and cesarean delivery (OR 1.76, 95% CI 0.99, 3.14). CONCLUSION: A false-positive GCT is an independent risk factor for adverse perinatal outcomes.     

Screening or diagnostic: markedly elevated glucose loading test and perinatal outcomes.

OBJECTIVE: To determine the diagnostic value of markedly elevated 50-g glucose loading test results (>or=200 mg/dL) and associated perinatal outcomes. METHOD: This was a retrospective cohort study of 14 771 pregnancies screened for gestational diabetes mellitus (GDM) between 1988 and 2001. The positive predictive value of the 50-g oral glucose loading test (GLT) results as measured by plasma glucose value was examined. Perinatal outcomes were assessed for women with GLT results >or=200 mg/dL compared to GLT <200 mg/dL, stratified by the diagnosis of GDM. Statistical comparisons were made using the Chi-square test and Student's t-test and potential confounding factors were controlled for using multivariable logistic regression analyses. A p value <0.05 and 95% confidence intervals were used to indicate statistical significance. RESULTS: The positive predictive values for a GDM diagnosis were 62% for GLT results between 180 and 189 mg/dL, 79% for those between 200 and 209 mg/dL, and 100% for GLT results >or=230 mg/dL. Compared to women with a GLT result <200 mg/dL, among women not diagnosed with GDM but with a GLT >or=200 mg/dL the adjusted odds ratio (aOR) for cesarean delivery was 4.18 (95% confidence intervals, 1.15-15.2). These women also had higher aORs for preterm delivery <32 weeks (aOR = 8.05 (1.02-63.6)), shoulder dystocia (aOR = 15.14 (1.64-140)), and their neonates were more likely to have a 5-minute Apgar score <7 (aOR = 6.41 (1.23-33.3)). For women diagnosed with GDM and with a GLT >or=200 mg/dL, the aOR for cesarean delivery was also elevated compared to those with a GLT <200 mg/dL (aOR = 2.24 (1.19-4.21)). CONCLUSION: A GLT value of >or=200 mg/dL is not absolutely diagnostic for gestational diabetes but is associated with unfavorable perinatal outcomes.     

Can adiponectin predict gestational diabetes?

The aim of the present study was to evaluate whether adiponectin is a predictive factor for gestational diabetes mellitus (GDM) and is appropriate as a screening test for GDM. Three-hundred and fifty-nine women with singleton pregnancy and indications for GDM screening according to criteria of the American College of Obstetricians and Gynecologists were enrolled in the study between July 5, 2004 and March 11, 2005. After confirming gestational age (GA) and number of fetuses by ultrasound, all women underwent a 1-h glucose challenge test with 50 g glucose load (50-g GCT) between 21 and 27 weeks of GA. Blood samples for determination of adiponectin levels were also obtained on the same day. Subsequently, between 24 and 28 weeks of GA, the women underwent an oral glucose tolerance test with 100 g glucose load (100-g OGTT). The diagnosis of GDM was established when two or more of the following criteria were fulfilled: (1) fasting glucose >95 mg/dl; (2) 1-h glucose >180 mg/dl; (3) 2-h glucose >155 mg/dl; (4) 3-h glucose >140 mg/dl. Sixty women were diagnosed with GDM, a prevalence of 16.7%. There was no difference in age between the GDM and non-GDM groups. Pre-pregnancy and sampling-day body mass index (BMI), increase in weight and all blood glucose levels were greater in women with GDM than in those without (p < 0.05). Adiponectin concentrations were significantly negatively correlated with GA and plasma glucose levels of the GCT and each OGTT. Using logistic regression analyses, adiponectin, but not age, pre-pregnancy BMI and increase in weight, was demonstrated as an independent predictive factor for GDM. The area under the receiver-operator characteristic curve of adiponectin was significantly lower than that of the GCT [0.63 (95% confidence interval (CI) 0.53-0.67) vs. 0.73 (95% CI 0.71-0.80), p < 0.001]. At a cut-off value of 140 mg/dl of the 50-g GCT, the sensitivity and specificity of the test were 90% and 61%, respectively. The 50-g GCT could identify GDM in 54 (90%) out of 60 women. On the other hand, at an arbitrary cut-off value of 10 microg/ml for adiponectin, sensitivity of 91% and specificity of 31% were achieved. If this cut-off value was used for ruling in or out pregnant women for the GDM screening, 27% of all women could be eliminated from needing to perform an OGTT, with five women (8.3%) misclassified. In conclusion, this study demonstrated that adiponectin was an independent predictor for GDM. As for GDM screening, adiponectin was not as strong a predictor as GCT. However, with advantage of being less cumbersome, adiponectin could be used to rule out pregnant women at low risk of GDM.     

Screening or diagnostic: Markedly elevated glucose loading test and perinatal outcomes

Objective.?To determine the diagnostic value of markedly elevated 50-g glucose loading test results (≥200 mg/dL) and associated perinatal outcomes.

Method.?This was a retrospective cohort study of 14 771 pregnancies screened for gestational diabetes mellitus (GDM) between 1988 and 2001. The positive predictive value of the 50-g oral glucose loading test (GLT) results as measured by plasma glucose value was examined. Perinatal outcomes were assessed for women with GLT results ≥200 mg/dL compared to GLT <200 mg/dL, stratified by the diagnosis of GDM. Statistical comparisons were made using the Chi-square test and Student's t-test and potential confounding factors were controlled for using multivariable logistic regression analyses. A p value <0.05 and 95% confidence intervals were used to indicate statistical significance.

Results.?The positive predictive values for a GDM diagnosis were 62% for GLT results between 180 and 189 mg/dL, 79% for those between 200 and 209 mg/dL, and 100% for GLT results ≥230 mg/dL. Compared to women with a GLT result <200 mg/dL, among women not diagnosed with GDM but with a GLT ≥200 mg/dL the adjusted odds ratio (aOR) for cesarean delivery was 4.18 (95% confidence intervals, 1.15–15.2). These women also had higher aORs for preterm delivery <32 weeks (aOR = 8.05 (1.02–63.6)), shoulder dystocia (aOR = 15.14 (1.64–140)), and their neonates were more likely to have a 5-minute Apgar score <7 (aOR = 6.41 (1.23–33.3)). For women diagnosed with GDM and with a GLT ≥200 mg/dL, the aOR for cesarean delivery was also elevated compared to those with a GLT <200 mg/dL (aOR = 2.24 (1.19–4.21)).

Conclusion.?A GLT value of ≥200 mg/dL is not absolutely diagnostic for gestational diabetes but is associated with unfavorable perinatal outcomes.     

Glucose screening in Mexican-American women

OBJECTIVE: We sought to describe the predictive value for gestational diabetes mellitus (GDM) using different glucose challenge test thresholds in Mexican-American women. METHODS: A prospective population-based study of 6,857 gravid women, who were tested with a 50-g glucose challenge test at 24-28 weeks of gestation, was performed. A screening value of 130 mg/dL or greater was followed by a 3-hour, 100-g oral glucose tolerance test. Gestational diabetes mellitus was diagnosed by 2 or more abnormal values using the Carpenter and Coustan criteria. For purpose of analysis, GDM diagnosis was categorized with glucose challenge test values in 10-mg/dL increments. A comparison between Carpenter-Coustan and the National Diabetic Data Group criteria for GDM diagnosis was performed for each glucose challenge test threshold category. Sensitivity and specificity for GDM diagnosis were further calculated for different glucose challenge test thresholds (130, 135, and 140 mg/dL). RESULTS: Overall, GDM was diagnosed in 469 of 6,857 (6.8%) women, and one abnormal oral glucose tolerance test value was tested in 351 of 6,857 women (5.1%). Normal glucose challenge test results (threshold less than 130 mg/dL) were obtained in 4,316 of 6,857 women. An elevated glucose challenge test value increases the risk of GDM, but even in high glucose challenge test thresholds (more than 180 mg/dL), the predictive value for GDM was only 50%. The sensitivity and specificity for GDM diagnosis using 3 different glucose challenge test thresholds were as follows: threshold 130 mg/dL or more: 97% and 63%; threshold 135 mg/dL or more: 91% and 73%; and threshold 140 mg/dL or more: 85% and 78%, respectively. CONCLUSION: Data suggests that an elevated glucose challenge test level cannot be used as a single diagnostic tool for GDM even in high test thresholds. A threshold of 130 mg/dL may be recommended as a screening threshold for GDM in Mexican-American women. LEVEL OF EVIDENCE: II-3     

50-Gram glucose challenge test: is it indicative of outcomes in women without gestational diabetes mellitus?

Objective.?To examine whether the 50-gram glucose challenge test (GCT) is associated with perinatal outcomes in women without gestational diabetes mellitus (GDM).

Methods.?This is a retrospective cohort study of 13,789 women who received the GCT and did not have a diagnosis of GDM at the University of California, San Francisco UCSF. GCT values were categorized and examined as predictors of perinatal morbidity using chi-square test and multivariable logistic regression analyses adjusting for maternal characteristics.

Results.?In women with an elevated GCT but without GDM, the odds of preeclampsia, cesarean delivery, and elevated birth weight were increased. The odds of large-for-gestational age status were increased with aOR 2.0 (95% CI 1.38–2.90) in the 160–179 mg/dl group. The odds of shoulder dystocia was increased with aOR 3.35 (CI 1.03–10.88) in the?≥180mg/dl group.

Conclusion.?In women without GDM, elevated 50-gram GCT values were associated with higher odds of perinatal morbidity. These findings further support evidence that impaired glucose tolerance is a continuum with possible associated adverse outcomes even at mild ranges; additional research is required to investigate appropriate interventions for women with abnormal screens for GDM.     

The 50-g glucose challenge test and pregnancy outcome in a multiethnic Asian population at high risk for gestational diabetes

Objective

To evaluate the 50-g glucose challenge test (GCT) on pregnancy outcome in a multiethnic Asian population at high risk for gestational diabetes (GDM).

Methods

GCT was positive if the 1-hour plasma glucose level was ≥ 7.2 mmol/L. GDM was diagnosed by a 75-g glucose tolerance test using WHO (1999) criteria. Of the 1368 women enrolled in the study, 892 were GCT negative, 308 were GCT false-positive, and 168 had GDM. Pregnancy outcomes were extracted from hospital records. Multivariable logistic regression analysis was performed with GCT negative women as the reference group.

Results

GCT false-positive status was associated with preterm birth (adjusted odds ratio [AOR] 2.1; 95% CI, 1.2-3.7) and postpartum hemorrhage (AOR 1.7; 95% CI, 1.0-2.7). GDM was associated with labor induction (AOR 5.0; 95% CI, 3.3-7.5), cesarean delivery (AOR 2.2; 95% CI, 1.6-3.2), postpartum hemorrhage (AOR 2.1; 95% CI, 1.2-3.7), and neonatal macrosomia (AOR 2.5; 95% CI, 1.0-6.0).

Conclusion

GCT false-positive women had an increased likelihood of an adverse pregnancy outcome. The role and threshold of the GCT needs re-evaluation.     

Does raising the glucose challenge test threshold impact birthweight in Asian gravidas?

OBJECTIVE: Some authors suggest a glucose challenge test (GCT) threshold of 150 mg/dL in Asian gravidas. The impact of such a policy on outcomes is unknown. STUDY DESIGN: A retrospective cohort of 1705 Asian gravidas. Subjects (n=95) had a GCT of 140-150 mg/dL and underwent a 3-h glucose tolerance test (GTT). Matched controls (n=190) had a GCT of <140 mg/dL. Birthweight was the primary outcome and the secondary outcomes were cesarean delivery (CD) rate and macrosomia. RESULTS: Eight subjects (11.9%) had gestational diabetes mellitus (GDM); none had GTT fasting values of >90 mg/dL. Mean birthweight was 3282 g in the subjects and 3238 g in the controls (P=0.39). There were no significant differences in the secondary outcomes. CONCLUSION: Compared with controls, study patients did not deliver significantly larger infants. However, raising the GCT threshold would have missed 8 subjects (11.9%) with GDM. Raising the GCT threshold to 150 mg/dL in Asian gravidas may unacceptably lower the sensitivity of the screening test.     

A population-based risk factor scoring will decrease unnecessary testing for the diagnosis of gestational diabetes mellitus

BACKGROUND: To determine the effectiveness of a population-based risk factor scoring to decrease unnecessary testing for the diagnosis of gestational diabetes mellitus (GDM). METHODS: We formed a risk factor scoring over five, which questions maternal age, body mass index and first-degree relatives with a diagnosis of diabetes mellitus, a prior macrosomic fetus and adverse outcome during the previous pregnancies. All participants underwent a 50-g glucose challenge test (GCT) followed by a 100-g oral glucose tolerence test (OGTT). We opened the 50-g GCT envelope if the participant had a risk score > or = 1 and opened the 100-g OGTT envelope if the 50-g GCT value was > or = 7.2 mmol/l. After all patients delivered we also built other strategies and tested their detection rates. RESULTS: Fourteen patients (3.3%) were diagnosed as having gestational diabetes mellitus via a 100-g OGTT. None of the patients with a score of zero had gestational diabetes mellitus. Logistic regression analysis revealed that an increase in the score by one caused a three times increase in gestational diabetes mellitus risk (OR = 3, CI = 1.9-5). Compared with the universal screening, our strategy to screen if the risk score was > or = 1, followed by a 50-g GCT with a 7.2-mmol/l cut-off value, decreased the number of women to be screened by 30% and diagnosed all cases with GDM. Screening the patients with a score > or = 2 would have decreased the number of women to be screened by 63%, still diagnosing 85% of cases with GDM. Also, risk factor-based screening strategies cause a 50% and 53% reduction in the number of OGTT applied, respectively. CONCLUSION: A well integrated, population-based scoring will decrease the number of unnecessary testing but still diagnose 85-100% of GDM cases.     

Can the 50-g glucose challenge test be important for subsequent pregnancies?

Aim: Our aim in this study was to examine the risk factors associated with gestational diabetes mellitus (GDM) in women who did not have GDM during a previous pregnancy. Materials and methods: In this retrospective cohort study, we reviewed the charts of all pregnant women who delivered two pregnancies between January 2000 and June 2010. Group 1 consisted of patients with gestational diabetes and Group 2 served as the control. Results: There were 743 women who underwent GDM screening by means of the 50-g glucose challenge test (GCT). Thirty-eight women (5.1%) were excluded because of a previous history of GDM. The recurrence of GDM was 42.1% in this group (16 of the 38). The remaining 705 patients were divided into the GDM group (n?=?38) and the control group (n?=?667). Undergoing a 50-g GCT during the previous pregnancy (p?=?0.000, 95% CI +0.01 to +0.002), age (p?=?0.009, 95% CI +0.001 to +0.009), and weight differences between the pregnancies at the first trimester (p?=?0.005, 95% CI +0.001 to +0.007) were independent parameters related to GDM. Conclusion: The 50-g GCT during the previous pregnancy was, interestingly, increased in the GDM group. It was also an independent risk factor for women without a history of GDM.     

Screening for gestational diabetes at antenatal booking in a Malaysian university hospital: the role of risk factors and threshold value for the 50-g glucose challenge test

BACKGROUND: The best method of screening for gestational diabetes (GDM) remains unsettled. The 50-g glucose challenge test (GCT) is used in a two-stage screening process but its best threshold value can vary according to population. AIMS: To evaluate the role of risk factors in conjunction with GCT and to determine an appropriate threshold for the one-hour venous plasma glucose with the GCT. METHOD: In a prospective study, 1600 women at antenatal booking without a history of diabetes mellitus or GDM filled a form on risk factors before GCT. Women who had GCT >or= 7.2 mmol/L underwent the 75-g oral glucose tolerance test (OGTT). GDM was diagnosed according to WHO (1999) criteria. RESULT: Thirty-five per cent had GCT >or= 7.2 mmol/L, 32.6% underwent OGTT and 34.5% of OGTT confirmed GDM. The GDM rate in our population was at least 11.4%. Examination of the receiver operator characteristic curve suggested that the best threshold value for the GCT in our population was >or= 7.6 mmol/L. Multivariable logistic regression demonstrated that only GCT >or= 7.6 mmol/L was an independent predictor for GDM (adjusted odds ratio 3.7: P < 0.001). After GCT, maternal age and anthropometry, OGTT during the third trimester, family history, obstetric history and glycosuria were not independent predictors of GDM. CONCLUSIONS: Risk factors were not independent predictors of GDM in women with GCT >or= 7.2 mmol/L. GCT threshold value >or= 7.6 mmol is appropriate for the Malaysian population at high risk of GDM.     

Association between inflammatory potential of diet and odds of gestational diabetes mellitus among Iranian women

Background: The possible relationship between diet-related inflammation and the risk of gestational diabetes mellitus (GDM) requires further investigation, especially in non-Western populations. We examined the association between dietary inflammatory index (DII) scores and GDM in a case-control study conducted in Iran.

Methods: This study included 122 GDM cases and 266 controls hospitalized for acute non-neoplastic diseases. Cases were pregnant women aged 18–40 years, who visited major general hospitals in different regions of Tehran. Pregnant women were screened for gestational diabetes between the 24th and 28th week of gestation with a 50-g, 1-hour glucose challenge test (GCT). Cases were diagnosed positive for GDM. Controls were pregnant women who had normal GCT test. DII scores were computed from dietary intake assessed by a previously validated 147-item food frequency questionnaire. Logistic regression models adjusted age, gestational age, energy, exercise, BMI, smoking exposure, family history of diabetes, and history of multivitamin intake were used to estimate odds ratios (ORs) and 95% confidence intervals (CI).

Results: Subjects with higher DII scores (i.e. indicating a more proinflammatory diet) had a higher odd of GDM with the DII being used as both a continuous (OR?=?1.20; 95% CI?=?0.94–1.54) and as categorical (OR_{tertile 3vs1}?=?2.10; 95% CI?=?1.02–4.34, p-trend?=?.03).

Conclusions: These results indicate that a proinflammatory diet, as evidenced by higher DII scores, is associated with increased odds of GDM among Iranian women.     

Gestational diabetes: fasting and postprandial glucose as first prenatal screening tests in a high-risk population

OBJECTIVE: To evaluate the value of fasting (FPG) and 2-hour postprandial (PPG) plasma glucose as screening tests for gestational diabetes mellitus (GDM) in a high-risk population during early pregnancy. STUDY DESIGN: At their first prenatal visit, 708 women underwent FPG and PPG for universal screening for GDM, with the diagnosis confirmed by the 75-g oral glucose tolerance test (World Health Organization criteria). The area under the receiver operating characteristic curve (AUC) was used to analyze the performance of the 2 screening tests. RESULTS: Of 184 (25.9%) women with GDM, 79 (42.9%) were identified before 18 weeks. The AUC for FPG to predict GDM was 0.579 (95% CI 0.531-0.627). Though a threshold of 85 mg/dL achieved minimally acceptable sensitivity, 79.9%, the corresponding specificity remained poor, 27.5%, with a false positive rate (FPR) of 72.5%. The AUC for PPG was 0.717 (95% CI 0.670-0.765); a cutoff of 95 mg/dL achieved a sensitivity of 79.9% and FPR of 53.1%. CONCLUSION: Though GDM could be diagnosed in > 40% women in early pregnancy at their first prenatal visit, the poor specificity and high FPR of FPG and PPG, alone or in combination, make them unsuitable screening tests for GDM.     

Maternal obesity and familial history of diabetes have opposing effects on infant birth weight in women with mild glucose intolerance in pregnancy.

OBJECTIVE: Pregnant women with an abnormal screening glucose challenge test (GCT) but without gestational diabetes mellitus (GDM) on subsequent oral glucose tolerance test (OGTT) are at increased risk of delivering macrosomic and large for gestational age (LGA) neonates. We thus sought to evaluate the maternal constitutional and biochemical factors that determine infant birth weight in this patient population. METHODS: Women with an abnormal GCT were evaluated at the time of their OGTT in late pregnancy. This analysis was restricted to Caucasian women without GDM (N = 86). Maternal demographic and biochemical factors were evaluated in relation to infant birth weight and LGA. RESULTS: After adjustment for length of gestation, birth weight was positively associated with pre-pregnancy body mass index (BMI) (r = 0.31, p = 0.0063) and negatively correlated with maternal serum levels of the insulin-sensitizing protein adiponectin (r = -0.30, p = 0.0084). On multiple linear regression analysis, pre-pregnancy BMI and weight gain in pregnancy were positive independent determinants of infant birth weight, while family history of diabetes emerged as a negative independent correlate. Logistic regression analysis confirmed that pre-pregnancy BMI was a positive predictor of LGA (odds ratio (OR) = 1.25, 95% confidence interval (CI) 1.05-1.49), whereas family history of diabetes was again identified as a negative determinant (OR = 0.10, 95% CI 0.02-0.59). In contrast, neither measures of glycemia nor insulin resistance/sensitivity were independently associated with birth weight or LGA. CONCLUSION: In pregnant women with an abnormal GCT but without GDM, pre-gravid maternal obesity predicts increased infant birth weight, whereas family history of diabetes is independently associated with decreased infant size.     

Gamma-glutamyltransferase level in pregnancy is an independent risk factor for gestational diabetes mellitus

Aim:  To evaluate the relationship between gamma-glutamyltransferase (GGT) level in pregnant women at oral glucose tolerance test (OGTT) and the diagnosis of gestational diabetes (GDM).
Methods:  Blood was taken for analyzing GGT level from women at high risk of GDM at the time of their scheduled OGTT. GDM was diagnosed according to World Health Organization 1999 criteria.
Results:  GGT level correlated positively with the 2-hour glucose level (Spearman's rho = 0.112: P  < 0.05). GGT values that were stratified into quartiles demonstrated a significant trend with diagnosis of GDM (χ² for trend; P  = 0.03). Multivariable logistic regression analysis taking into account maternal age, gestational age at OGTT, body mass index and a positive 50-g glucose challenge test (GCT) indicated that high GGT was an independent risk factor for GDM (adjusted odds ratio [AOR] 2.1 95% CI 1.2–3.8: P  = 0.01). In the subset of women identified by a positive GCT, on multivariable logistic regression analysis, only high GGT was an independent risk factor for GDM (AOR 2.3 95% CI 1.3–4.2: P  = 0.007).
Conclusion:  Raised GGT level is an independent risk factor for GDM in high risk pregnant women undergoing OGTT.     

Screening for gestational diabetes mellitus in adolescent Hispanic Americans

OBJECTIVE: To determine the incidence of gestational diabetes mellitus (GDM) in an adolescent Hispanic American population. STUDY DESIGN: A retrospective review of 326 women < 20 years of age who identified themselves as Hispanic American was conducted and the incidence of gestational diabetes determined. RESULTS: Thirty adolescent Hispanic Americans (9.2%) had an abnormal result (> or = 140 mg/dL) after 50-g, one-hour oral glucose challenge testing. These women underwent three-hour oral glucose tolerance tests, and five met the criteria for GDM. The incidence of GDM in this population was 1.5% (5/326) (95% confidence interval, 0.6, 3.7). CONCLUSION: The incidence of GDM in adolescent Hispanic Americans is so low that universal screening may not be warranted.     

Glyburide in gestational diabetes – prediction of treatment failure

Objective.?To identify factors predicting failure of glyburide treatment in women with gestational diabetes mellitus (GDM).

Methods.?A retrospective study of all women with GDM that were treated with glyburide in a single tertiary referral center. Patients were switched from glyburide to insulin if they failed to achieve glycemic goals, and were then classified as glyburide failure.

Results.?Overall, 124 women with GDM treated with glyburide were included in the study, of which 31 (25%) failed to achieve glycemic control. Women in the failure group were characterized by a higher weight gain during pregnancy, higher rates of GDM on previous pregnancies, and a glucose challenge test (GCT) result. On multivariate logistic regression analysis, a GCT value of >200?mg/dl (OR=7.1, 95% CI 2.8–27.6) and weight gain ≥12?kg (OR=3.9, 95% CI 1.2–13.0) were the only significant and independent predictors of glyburide failure. Most women who were successfully treated with glyburide required a daily dose of 5?mg or less and the time required to achieve glycemic control in these cases was 12.4±4.9 days (range 5–24 days). Of the women who failed to achieve glycemic control with gluburide, 26/31 were switched to insulin, of them only 12 (46%) achieved desired level of glycemic control.

Conclusion.?Most women with GDM achieved desired level of glycemic control under glyburide treatment.