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.     

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.     

Screening for gestational diabetes mellitus by a model based on risk indicators: a prospective study

OBJECTIVE: This study was performed to prospectively evaluate a screening model for gestational diabetes mellitus on the basis of clinical risk indicators. STUDY DESIGN: In a prospective multicenter study with 5235 consecutive pregnant women, diagnostic testing with a 2-hour 75-g oral glucose tolerance test was routinely performed in women with risk indicators and offered to women without risk indicators as part of the study. RESULTS: Forty-four percent of the women underwent testing, 43% declined participation, 6% did not speak Danish, and 7% could not be contacted. By extrapolation of the results from tested women to the whole group in question, a 2.4% prevalence of gestational diabetes mellitus was calculated. Sensitivity and specificity of the model was 80.6 (73.7-87.6) and 64.8 (63.5-66.1), respectively (95% CIs). CONCLUSION: Under ideal conditions, sensitivity of the model was comparable with universal screening by fasting glucose or a 1-hour 50-g glucose challenge test. Both screening and diagnostic testing could be avoided in two thirds of all pregnant women.     

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 southern Asian women

AIM: To compare fasting plasma glucose (FPG) against 2-h postprandial plasma glucose (PPPG), following a carbohydrate meal, for screening of gestational diabetes mellitus (GDM) in southern Asian women with one or more risk factors. METHODS: A comparative study was conducted at a university obstetric unit in Sri Lanka. Two hundred and seventy one women undergoing oral glucose tolerance test (OGTT) according to the WHO criteria of 1999 had a 2-h PPPG performed within the following week. Sensitivity, specificity, predictive values and correlation coefficients for predicting a diagnosis of GDM and areas under receiver-operator curves (ROC) were calculated for FPG and PPPG. The ability to predict GDM and to reduce the need for OGTT were the main outcome measures. RESULTS: The mean period of gestation was 26.43 weeks (SD = 5.4) Seventy-five (27.7%) women were diagnosed with GDM. The optimal threshold for FPG was 4.4 mmol/L and for PPPG 4.7 mmol/L. At these, sensitivity was 92.0% and 90.7%, specificity 48.7% and 25.4% and the areas under the ROC 0.82 and 0.73 for FPG and PPPG, respectively. Nine (12%) women could be diagnosed as having GDM on the basis of the FPG being above the threshold. CONCLUSIONS: FPG is superior to 2-h PPPG for screening high-risk women for GDM. Nine women were diagnosed as having GDM on the basis of having an FPG above 7 mmol/L. FPG could reduce the number of OGTT needed by 40.9%, compared to 20.6% by PPPG. FPG is a less cumbersome and cost-effective screening test.     

Fasting capillary glucose as a screening test for gestational diabetes mellitus

Objective  To evaluate fasting capillary glucose as a screening test for gestational diabetes mellitus (GDM) compared with traditional risk factors and repeated random capillary glucose measurements.
Design  Cross-sectional, population-based study.
Setting  Maternal Health Care Clinics in Örebro County, Sweden.
Population  An unselected population of women without diabetes.
Methods  Fasting capillary glucose levels were measured at gestational weeks 28–32. Random capillary glucose levels were measured four to six times during pregnancy. Traditional risk factors for GDM were registered. GDM was diagnosed using a 75-g oral glucose tolerance test.
Main outcome measures  Sensitivity, specificity, likelihood ratios.
Results  In 55 of 3616 women participating in the study, GDM was diagnosed before 34 weeks of gestation. For fasting capillary glucose cutoff values between 4.0 and 5.0 mmol/l, sensitivity was in the range between 87 and 47% and specificity between 51 and 96%. Using a combined screening model of traditional risk factors with fasting capillary glucose at various cutoff values increased the sensitivity only slightly compared with using fasting capillary glucose alone.
Conclusion  In this Swedish, unselected, low-risk population, fasting capillary glucose measurements were found to be an acceptable and useful screening test for GDM.     

对8 665例孕妇行妊娠期糖尿病筛查的临床研究

目的探讨50 g葡萄糖负荷试验 (GCT) 筛查妊娠期糖尿病( GDM) 的阈值、适宜孕周,孕妇年龄和体重因素对GDM发生的影响.方法采用回顾性研究的方法,对1995年1月至2001年3月在北京大学第一医院妇产科行GCT的8 665例孕妇的临床资料进行分析.结果 (1)8 665例孕妇 GCT 1 h平均血糖水平为(6.8±1.7) mmol/L,以7.8 mmol/L为切点,GCT异常率为25.2%,GDM漏诊率为5.3%(17/321);以7.2 mmol/L为切点,GCT异常率为36.5%,GDM漏诊率为2.8 %(9/321);以8.3 mmol/L为切点,GDM漏诊率为15.9%(51/321). (2)GCT 1 h血糖≥11.2 mmol/L者中,GDM发生率为55.8%(92/165),其中62.0%(57/92)根据空腹血糖水平可以做出诊断.(3)孕24周以后,不同孕周间GCT异常率无差异.(4)GCT异常率和GDM发生率不同年龄组比较,差异有极显著性(P<0.01),25岁以下无GDM高危因素的孕妇GDM发生率为0.3%,显著低于年龄≥25岁的孕妇.(5)孕26～28周时孕妇的平均体重指数(BMI)为(24.9±2.9) kg/m2(±s),当BMI≥27.8时,GCT异常率和GDM发生率均显著增高.结论 (1)GCT筛查GDM以7.8 mmol/L为切点是合理的; GCT 1 h血糖≥11.2 mmol/L 时,应先行空腹血糖检查确诊是否为GDM.(2)孕24周后尽早行GCT是恰当的,但对于有明显高危因素者应在孕24周前行GCT.(3)孕妇年龄和体重与GDM的发生密切相关,25岁以下无高危因素者可以不行GDM筛查.     

Use of oral glucose tolerance test in early pregnancy to predict late-onset gestational diabetes mellitus in high-risk women

AIM: To evaluate if any single plasma glucose level from the four values of the normal 100-g oral glucose tolerance test (OGTT) in early pregnancy (< or =20 weeks of gestation) could predict gestational diabetes mellitus (GDM) diagnosed from a second OGTT in late pregnancy (28-32 weeks). METHODS: Glucose levels of pregnant women at high-risk for GDM, who had had a normal early OGTT, and who underwent the second test in late pregnancy, were studied. Each of the four plasma glucose values of the early OGTT was determined for sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). The receiver operating characteristic curves of these four OGTT values were then constructed to find the optimal value to predict late-onset GDM. RESULTS: Of 193 pregnant women who had had a normal early OGTT, 154 also had a normal OGTT in late pregnancy while 39 had an abnormal test and were diagnosed with GDM. Among the four glucose values of the early OGTT, the 1-h value yielded the best diagnostic performance to predict late-onset GDM. The sensitivity, specificity, PPV, NPV, and area under the curve achieved from its optimal cutoff level of > or =155 mg/dL (8.6 mmol/L) were 89.7%, 64.3%, 38.9%, 96.1%, and 0.77, respectively. CONCLUSIONS: A 1-h glucose value > or =155 mg/dL at the early OGTT yielded the best diagnostic performance. However, the low specificity and PPV rendered it suboptimal to predict late-onset GDM. Nevertheless, a considerable number of high-risk women could avoid the second OGTT in late pregnancy due to its high sensitivity and NPV.     

口服葡萄糖耐量试验中空腹血糖水平在妊娠期糖尿病诊断中的作用

目的 探讨妊娠24～28周间口服葡萄糖耐量试验(oral glucose tolerance test,OGTT)中空腹血糖值在诊断妊娠期糖尿病(gestational diabetes mellitus,GDM)中的作用. 方法 对2010年1月1日至12月31日间,于首都医科大学附属北京妇产医院产前检查,妊娠早期空腹血糖正常(＜7.0 mmol/L),妊娠24～28周50 g葡萄糖负荷试验≥7.8 mmol/L并行75 g OGTT的6516例孕妇的OGTT结果进行分组分析.采用卡方检验,了解按OGTT空腹血糖水平分组后GDM的诊断情况. 结果 按国际糖尿病与妊娠研究组(International Association of Diabetes and Pregnancy Study Groups,IADPSG)的GDM诊断标准,单纯依据OGTT空腹血糖升高(≥5.1 mmol/L)可诊断15.0％(980/6516)的GDM患者,剔除这部分患者后,余OGTT空腹血糖＜5.1 mmol/L的5536例孕妇纳入分组分析.以OGTT中空腹血糖值每升高0.1 mmol/L为1个分界进行第1次分组,结果显示,随着空腹血糖水平的升高,GDM的诊断率逐渐增加(X2=282.175,P=0.000).按照空腹血糖在4.0～4.8 mmol/L间每升高0.2 mmol/L为1个分界进行第2次分组分析,显示随着空腹血糖水平的升高,各组GDM诊断率仍呈现升高趋势(X2=274.364,P=0.000).两种分组结果均显示,当OGTT中空腹血糖水平＜4.2 mmol/L(1226/5536,占22.1％)时,GDM诊断率为3.6％(44/1226),可以考虑对该部分患者暂时不行OGTT检测;当OGTT中空腹血糖水平≥4.8 mmol/L时,GDM诊断率明显增加,为26.2％(298/1138),故应提高警惕. 结论 妊娠24～28周行OGTT前建议先行空腹血糖筛查,空腹血糖≤4.2 mmol/L的低危孕妇可免于OGTT检测.     

妊娠期口服葡萄糖负荷试验合理血糖界值的探讨

目的 探讨目前适合我国卫生经济条件的妊娠期葡萄糖负荷试验(GCT)的筛查界值.方法 资料来源于2006年4月1日至2006年9月30日在全国18个城市25家医院保健并进行首次50 g GCT的16 286例孕妇,对其GCT结果进行统计和分析.结果 以NDDG标准诊断妊娠期糖尿病(GDM),50 g GCT的界值选取7.2 mmol/L时的敏感度和特异度分别为98.2%和59.0%,选取7.8 mmol/L时分别为96.0%和73.0%,选取8.3 mmol/L时分别为90.2%和81.5%;以ADA标准诊断GDM,选取GCT界值为7.2 mmol/L时敏感度为97.9%,特异度为60.4%;选取7.8 mmol/L时分别为96.2%和74.7%;而选取8.3 mmol/L则分别为87.0%和83.1%.以NDDG标准诊断妊娠期糖代谢异常(包括GDM及妊娠期糖耐量受损),选取7.2 mmol/L时敏感度和特异度分别为97.7%和61.4%,选取7.8 mmol/L时分别为95.4%和75.8%,选取8.3 mmol/L时分别为84.9%和84.1%.结论 据我国目前的卫生经济情况,以7.8 mmol/L作为50 g GCT的界值是合理的.     

Postnatal testing for diabetes in Australian women following gestational diabetes mellitus

Background:  Postnatal blood glucose testing is recommended for reclassification of glucose tolerance following a pregnancy affected by gestational diabetes mellitus (GDM); however, there are limited data on the postnatal follow-up sought by Australian women.
Aims:  To describe postnatal diabetes testing patterns in Australian women following a pregnancy affected by GDM and identify factors associated with return for follow-up testing in accordance with the Australasian Diabetes in Pregnancy Society (ADIPS) guidelines.
Methods:  A cross-sectional self-administered survey of 1372 women diagnosed with GDM between 2003 and 2005, sampled from the National Diabetes Services Scheme database.
Results:  Postnatal diabetes testing was reported by 73.2% of survey respondents with 27.4% returning for an oral glucose test tolerance at six to eight weeks post-GDM pregnancy. Using logistic regression analysis, factors associated with appropriate postnatal testing were receiving individualised risk reduction advice (odds ratio (OR) 1.41 (1.08,1.84)) or written information (OR 1.35 (1.03,1.76)) and in two-way interactions, being under the care of an endocrinologist and not tertiary educated (OR 2.09 (1.49,2.93)) as well as seeing an obstetrician and diabetes educator during pregnancy (OR 1.72 (1.19,2.48)). Every five years increase in age reduced the likelihood of a woman returning for testing by 17%.
Conclusions:  Specialist diabetes care in non-tertiary educated women, or a team approach to management with diabetes education and obstetric care may act to reinforce the need for postnatal diabetes testing in accordance with the ADIPS guidelines. Individualised follow up from a health professional and provision of written information following a GDM pregnancy may also encourage return for postnatal testing in this high-risk group.     

Screening for gestational diabetes: the effect of varying blood glucose definitions in the prediction of adverse maternal and infant health outcomes

BACKGROUND: Impaired glucose tolerance in pregnancy and gestational diabetes are associated with increased maternal and fetal risks. There is considerable uncertainty in the literature relating to the merits of screening for gestational diabetes and impaired glucose tolerance, and variable definitions in the cut-off values to be used. AIMS: To assess different levels of glucose intolerance in predicting adverse pregnancy outcomes. METHODS: Retrospective cohort study involving screening pregnant women with a 50-g oral glucose load, followed by a formal 75-g oral glucose tolerance test for women who screened positive (defined as a plasma glucose level > or = 7.8 mmol/L). Plasma glucose results were correlated with pregnancy and birth outcomes, and receiver-operator curves were constructed. RESULTS: A total of 16,975 women were screened with a glucose challenge test, with pregnancy outcome information available for 1804 women who screened positive on glucose challenge test. With increasing plasma glucose values, there was a significant increase in pre-eclampsia, Caesarean section, shoulder dystocia and neonatal hypoglycaemia. CONCLUSIONS: The risk of adverse maternal and infant pregnancy outcomes increases with increasing levels of glucose impairment despite treatment.     

Risk factors for postpartum glucose intolerance in women with gestational diabetes mellitus

Objectives: To determine the risk factors for glucose intolerance (GI) during the postpartum period in women with gestational diabetes mellitus (GDM).

Methods: This prospective cohort study included 72 Japanese women with GDM who underwent 75?g oral glucose tolerance tests (OGTT) at 12 weeks after delivery. These women were divided into the GI group and the normal group based on postpartum OGTT. Risk factors for GI, including levels of blood glucose (BG), area under the curve (AUC) of glucose, AUC insulin, HbA1c, homeostasis model assessment-insulin resistance (HOMA-IR), HOMA-β, insulinogenic index (II) and the oral disposition index (DI) in antepartum OGTT, were analyzed by logistic regression analyses.

Results: Of the 72 women, 60 (83.3%) were normal and 12 (16.7%) had GI. By univariate logistic regression analyses, fasting BG, AUC glucose, HOMA-β, II and oral DI were selected as risk factors for GI. Multivariate logistic regression analysis revealed that the level of II in antepartum OGTT was a significant factor that predicted GI after delivery (odds ratio, 0.008; 95% CI, 0.0001–0.9; p?Conclusions: II measured by OGTT during pregnancy might be a useful predictor of GI within the early postpartum period in women with GDM.     

Women with gestational diabetes mellitus in the ACHOIS trial: risk factors for shoulder dystocia

BACKGROUND: Gestational diabetes mellitus (GDM) is associated with increased risk of fetal macrosomia and shoulder dystocia. However, not all women with GDM and fetal macrosomia have shoulder dystocia. Aims: To identify the risk factors for shoulder dystocia in women with gestational diabetes using data from women recruited into the routine care group of the ACHOIS trial. METHODS: A secondary analysis was performed on data collected from women enrolled in the ACHOIS trial. Bivariate analyses were performed using the Fisher exact test. Variables found to be significantly associated with shoulder dystocia and previously identified risk factors were used as explanatory variables in multivariate analyses. RESULTS: A positive relationship was found between the severity of maternal fasting hyperglycaemia and the risk of shoulder dystocia, with a 1 mmol increase in fasting oral glucose-tolerance test leading to a relative risk (RR) of 2.09 (95% CI 1.03-4.25). Shoulder dystocia occurred more often in births requiring operative vaginal delivery (RR 9.58, 95% CI 3.70-24.81, P < 0.001). Macrosomic and large-for-gestational-age infants were more likely to have births complicated by shoulder dystocia (RR 6.27, 95% CI 2.33-16.88, P < 0.001 and RR 4.57, 95% CI 1.74-12.01, P < 0.005, respectively). Fetal macrosomia was the only variable to maintain its significance in all multivariate analyses. CONCLUSIONS: Fetal macrosomia is the strongest independent risk factor for shoulder dystocia. Effective preventative strategies are needed.     

A comparison between a 75-g and 100-g oral glucose tolerance test in pregnant women.

OBJECTIVES: To test the validity of a 75-g, 2-h oral glucose tolerance test (OGTT) for diagnosing gestational diabetes mellitus (GDM) using the criteria and reference values suggested by the American Diabetes Association for the 100-g, 3-h OGTT. METHODS: The results of a 75-g, 2-h OGTT were compared with those of a 100-g, 3-h OGTT in 42 pregnant women. The women's mean+/-S.D. age and gestational age were 33.6+/-5.4 years and 28.2+/-4.2 weeks, respectively. Each subject was randomly scheduled within 1 week for both the 75-g and 100-g OGTTs. RESULTS: The mean plasma glucose concentrations at 1, 2, and 3 h during the 100-g OGTT were significantly higher than those during the 75-g OGTT. Using the Carpenter and Coustan criteria, the prevalence of GDM was 21.4% when using the 100-g, 3-h OGTT, whereas it was found to be at only 7.1% when using the 75-g, 2-h OGTT. CONCLUSIONS: Plasma glucose responses during the 75-g OGTT were found to be lower than those during the 100-g OGTT. When using the same diagnostic criteria, the prevalence of GDM was also found lower using the 75-g glucose load. It would therefore not be appropriate to use the 75-g OGTT for diagnosing GDM using the criteria and reference values of the 100-g OGTT. To give a comparable prevalence of GDM, the threshold of abnormal plasma glucose levels of the 75-g OGTT would need to be lower than that of the 100-g OGTT.     

Accuracy of the random glucose test as screening test for gestational diabetes mellitus: a systematic review

Objective

Although not formally supported by guidelines, random glucose testing (RGT) is frequently used to screen for gestational diabetes mellitus (GDM). Results on test accuracy are inconclusive. The aim of this study was to systematically review the literature and calculate summary estimates of accuracy measures of RGT as screening test for GDM.

Study design

Systematic review to identify studies comparing RGT to oral glucose tolerance testing before 32 weeks of pregnancy. A systematic search without language restrictions was performed in MEDLINE (1950 till April 2008) and EMBASE (1980 to April 2008). Study selection and data extraction were performed by two independent reviewers. Outcome measures were summary estimates of test accuracy of RGT.

Results

Six studies were included, reporting on 3537 women. Due to the small number of studies and heterogeneity, no summary estimates of test accuracy were calculated. Reported sensitivities and specificities of individual studies varied. For 100% sensitivity, specificity was around 40%. For sensitivity of 60% specificity was at most 80%. When specificity approached 100%, sensitivity dropped to 20-30%.

Conclusion

Available evidence on the accuracy of RGT to test for GDM is limited. Based on studies in our systematic review, we consider single random glucose measurement inadequate to screen for GDM.     

Screening for gestational diabetes in the 21st century: a population-based cohort study in Israel

Objective: Studies indicate that gestational diabetes mellitus (GDM) prevalence is increasing worldwide. We aimed to examine secular trends in GDM prevalence and screening practices over the last decade in Israel, and to identify changes in GDM risk factors. Methods: We collected data on all 367,247 pregnant women who were screened for GDM between 2000 and 2010 in Israel’s second largest healthcare organization. Multivariable logistic regression analysis was used to identify risk factors for GDM. Results: GDM prevalence increased by 12%, from 3.8% in 2000 to 4.3% in 2010 and was accompanied by a 37% rise in the proportion screened directly by 100-gram oral glucose tolerance test without a prior 50-gram glucose challenge test (from 6.5% to 8.9%). During the study period there was an on-going increment in the proportion of pregnant women with one or more GDM risk factor, such as older age, low socioeconomic level, history of polycystic ovary syndrome or in vitro fertilization, which was all significantly (p < 0.05) associated with the risk of GDM. Conclusions: The increasing risk of GDM in Israel can be explained by both rising prevalence of women with established risk factors, as well as shifting screening practices.