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.     

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.     

妊娠期葡萄糖耐量受损与胰岛素抵抗

目的　探讨妊娠期葡萄糖耐量受损 (im paired glucose tolerance test,IGT)与胰岛素抵抗之间的关系。　方法　选取 1999年 5月至 1999年 8月在上海市 11家医院产前检查 ,且葡萄糖耐量试验四项结果中有一项异常的孕妇 93例 ,随机选取无糖耐量受损的孕妇 179例 ,同时进行胰岛素释放试验 ,并计算胰岛素敏感性指数及胰岛分泌功能指数 ,比较两组胰岛素敏感性指数 (ISI)、胰岛分泌功能指数 (IFI)、空腹血糖 (PGO)、空腹胰岛素水平 (INO)、血糖曲线下面积 (SAUC)及胰岛素曲线下面积 (IAU C)的差异。　结果　葡萄糖耐量受损的 IGT组与正常组 PGO、IS0、SAUC、IAU C、及 ISI分别为 (5 .1± 1.0 ) m mol/ L 和 (4.3± 0 .4) mm ol/ L、(142± 77) pmol/ L 和 (114± 40 ) pm ol/ L、(2 3± 4)mm ol/ L 和 (18± 3) m mol/ L、 (1186± 437) pmol/ L 和 (10 5 8± 40 7) pm ol/ L、及 30± 2 0和 2 2± 2 4,两者比较差异均有显著性 (P<0 .0 5 )。而 IGT组与正常组 IFI分别为 2 8± 14和 2 6± 9,两组比较差异无显著性 (P>0 .0 5 )。　结论　胰岛素抵抗是 IGT的病因之一。     

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.     

妊娠期糖代谢异常导致巨大儿发生的危险因素分析

目的:探讨妊娠期糖代谢异常导致巨大儿发生的相关危险因素,为降低巨大儿的出生率提供科学依据。方法:回顾性分析2007年1月至2009年4月上海市第六人民医院产科收治的妊娠期糖尿病(GDM)孕妇125例和妊娠期糖耐量减低(GIGT)孕妇21例的临床资料。根据是否分娩巨大儿分为两组,采用t检验、卡方检验和多因素Logistic回归分析巨大儿发生的相关危险因素。结果:①单因素分析提示:与非巨大儿组孕妇相比,巨大儿组孕妇的糖尿病家族史、曾分娩巨大儿史、孕前体重、孕期体重增加、空腹血糖水平、OGTT-1小时血糖水平等因素分布差异有统计学意义(P<0.05)。②Logistic多因素回归分析提示:空腹血糖水平升高、孕期体重增加、糖尿病家族史、分娩巨大儿史是巨大儿发生的主要危险因素。③空腹血糖≥5.3mmol/L的孕妇,随着血糖水平的升高,发生巨大儿的风险亦明显增加。结论:对妊娠期糖代谢异常孕妇,应加强其孕期体重和空腹血糖水平的监护和管理,以减少巨大儿的发生及改善相关不良妊娠结局。     

The association between serum ghrelin levels and large-for-gestational-age fetuses in patients with gestational diabetes mellitus

We aimed to determine the relationship between serum ghrelin levels and large-for-gestational-age (LGA) fetuses in patients with gestational diabetes mellitus (GDM). A case-control study was conducted in 32 women with GDM and LGA fetuses (GDM?+?LGA group), 35 women with GDM and appropriate-for-gestational-age (AGA) fetuses (GDM?+?AGA group), 32 women with normal glucose tolerance (NGT) and LGA fetuses (NGT?+?LGA group), and 31 women with NGT and AGA fetuses (NGT?+?AGA group). All participants were recruited at the time of GDM diagnosis between 24 and 30 weeks of pregnancy. Participants also underwent ultrasonographic examinations. Serum ghrelin levels were significantly higher in GDM?+?LGA and GDM?+?AGA groups than in the NGT?+?AGA group. In the univariate model, biparietal diameter, head circumference, abdominal circumference (AC), femur length and ghrelin values were significant predictors of LGA fetuses. In the multivariate model, only AC remained as a predictor of LGA fetuses.     

妊娠期糖耐量异常妇女胰岛功能与胰岛素抵抗的相关研究

目的:研究妊娠期糖耐量异常与胰岛β细胞功能、胰岛素抵抗等的关系。方法:对孕24~36周上海市孕妇共4568例(孕前有糖尿病或糖尿病家族史者排除),先行50g葡萄糖筛查试验,异常者再行75g口服葡萄糖耐量试验(OGTT)-胰岛素释放试验,选取OG-TT异常者318例作为试验组,OGTT正常者中随机选取320例作为对照组,获取各阶段的血糖值及血清胰岛素值,通过计算,用胰岛素敏感指数(ISI)、稳态评估模式、胰岛素储备能力/血糖最大升高值(ΔPI/ΔPG)了解胰岛β细胞功能及外周胰岛素抵抗情况。结果:OGTT异常组的OGTT后1h血清胰岛素(PI1)、胰岛素释放曲线下面积较OGTT正常组显著增高(P<0·05),而胰岛素敏感指数、ΔPI/ΔPG及HOMA-β细胞较OGTT正常组降低(P<0.05)。糖尿病(GDM)组与妊娠期糖耐量减退(GIGT)组相比:GDM组的BMI高于GIGT组,而胰岛素敏感指数、HOMA-β细胞低于GIGT组(P<0.05)。其它指标均无明显差异。结论:妊娠期糖耐量异常形成的主要原因为胰岛素抵抗而非胰岛分泌功能降低。     

Adiponectin and glucose levels in women with negative or false positive glucose challenge test

OBJECTIVE: To determine whether there is a correlation between adiponectin levels and glucose levels in women screened for gestational diabetes mellitus by means of a 50-g oral glucose challenge test, and to examine the difference in adiponectin levels between women who tested negative, and those who tested false positive. We further calculated the correlations between adiponectin levels and glucose levels, body mass index, gestational age and maternal age. METHODS: A case control study included 171 mothers with negative or false positive results in the 1-h 50-g glucose challenge test at 24-28 gestational weeks. Serum adiponectin levels were determined by radioimmunoassay at the time of the glucose challenge test. RESULTS: There was a significant difference between women who tested negative at screening, and those who tested false positive with respect to age, prepregnancy body weight and body mass index, and adiponectin levels. Correlation analysis showed adiponectin levels to be negatively correlated to glucose levels (r=-0.193, P=0.011). To examine the association between glucose levels, adiponectin levels and demographic variables, multiple linear regression analysis was carried out. Prepregnancy body mass index and age accounted for 14.6% of the variance in the glucose challenge test. Adiponectin levels did not contribute independently to the variation in glucose levels. A further multiple linear regression analysis was undertaken to investigate the association between adiponectin levels and age, prepregnancy body mass index and glucose levels in the glucose challenge test. In this regression model, prepregnancy body mass index and age explained 12.1% of the variance in adiponectin levels. CONCLUSIONS: In conclusion, our study indicated a negative correlation between adiponectin and glucose levels in women screened for gestational diabetes mellitus by a glucose challenge test. We further found that maternal age and body mass index were independent risk factors for a false positive glucose challenge test. Reduced adiponectin levels in women who tested false positive on the glucose challenge test were dependent on advanced age and higher body mass index.     

The risk of metabolic syndrome in women with previous GDM in a long-term follow-up

The aim of this study was to evaluate the incidence of metabolic syndrome (MetS) during long-term follow-up of women with gestational diabetes (GDM). Furthermore, we evaluated the glycemic measures from an oral glucose tolerance test (OGTT) during pregnancy as predictors of incident MetS. Women diagnosed with GDM were divided into two groups according to the results of OGTT: one abnormal value?=?GDM1 (n?=?338) and two abnormal values?=?GDM2 (n?=?151), while women with normal glucose tolerance (n?=?385) served as controls. MetS and its components were evaluated in a follow-up study (mean follow-up time 7.3?±?5.1 years) according to the International Diabetes Federation (IDF) criteria. Fasting plasma glucose in OGTT was the best predictor of incident MetS in ROC (area under the curve) analysis. The incidence of MetS during a <5-year follow-up was 22.2% in controls, 39.3% in GDM1 and 60.4% in GDM2; and >10-year follow-up 24.2%, 46.2% and 62.5%, respectively. In controls and GDM2, the incidence of MetS remained nearly constant during the follow-up, whereas in GDM1 it increased. In conclusion, already mild gestational glucose intolerance may progress to MetS and therefore merits intervention measures to prevent future cardiovascular disease.     

Relative Importance of Maternal Constitutional Factors and Glucose Intolerance of Pregnancy in the Development of Newborn Macrosomia

The purpose of this case-control study was to determine the relative importance of various predictors of newborn macrosomia, with particular reference to maternal constitutional factors and glucose intolerance of pregnancy. Macrosomia was defined by both absolute birthweight ±4,000 g and birthweight ±90th centile for gestational age. One thousand mother/newborn pairs [209 macrosomic (cases) and 791 non-macrosomic newborns (controls)] were recruited. Mothers with pre-gestational diabetes mellitus were excluded. Data on prepregnancy and pregnancy variables were collected by review of prenatal, labour, and delivery and newborn assessment records and interview with the mother.

Predictors that entered the stepwise multiple regression model in order of significance were: previous history of macrosomia, increasing maternal weight, nonsmoking status, multiparity, male newborn gender, gestational age of 40–42 weeks, North American Aboriginal ethnicity, maternal birthweight >4,000 g, maternal height and maternal age >17 years. Glucose screen positive/100-g oral glucose tolerance test (GTT) negative status was a significant predictor for macrosomia as defined by birthweight greater than the 90th percentile for gestational age, but not for absolute birthweight over 4,000 g. It was the least significant of all the factors examined. Treated gestational diabetes was not a significant predictor.

By multivariate analysis, maternal constitutional factors are more powerful predictors of newborn macrosomia than maternal mild glucose intolerance. Treatment of mothers with GDM may be masking the effect of more pronounced carbohydrate intolerance.     

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.     

Obstetrical outcomes in patients with early onset gestational diabetes

Objective: The objective of this study was to characterize patients with early onset gestational diabetes and compare outcomes to patients diagnosed with standard gestational diabetes and pregestational diabetes.

Methods: This is a retrospective cohort study of patients diagnosed with gestational or pregestational diabetes. All patients received a glucose challenge test at their first prenatal visit to diagnose early onset gestational diabetes and were recommended to have postpartum glucose tolerance tests to detect undiagnosed type 2 diabetes. Outcomes were compared between patients with early onset gestational diabetes and both standard gestational diabetes and pregestational diabetes with p?<?0.05 was used for significance.

Results: Four hundred and twenty-four patients met the inclusion criteria. Nine percent of the patients with early onset gestational diabetes were found to have undiagnosed type 2 diabetes based on postpartum testing and 91% to have resolution in the postpartum period. No patient with early onset gestational diabetes and resolution in the postpartum period had abnormal screening for renal or ophthalmologic disease, but 5% had abnormal fetal echocardiograms. These patients were more likely to require pharmacotherapy for glycemic control than patients with standard gestational diabetes and less likely than patients with pregestational diabetes (55% versus 39% versus 81%).

Conclusion: Most patients diagnosed with early onset gestational diabetes do not have undiagnosed type 2 diabetes but do have unique characteristics and obstetrical outcomes.     

妊娠期糖尿病空腹血糖筛查的意义及其对妊娠结局的影响

妊娠期糖尿病(gestational diabetes mellitus,GDM)的发生率逐年上升,不良妊娠结局与血糖水平相关,即使妊娠妇女的血糖水平在正常范围,随着血糖水平的升高,大于胎龄儿、剖宫产率、新生儿低血糖、新生儿高胰岛素血症及生后糖尿病的发生等母儿不良预后的发生率增加,尽早诊断及治疗GDM有助于改善不良妊娠结局。利用空腹血糖(fasting plasma glucose,FPG)筛查GDM越来越受关注。其具有操作简单,价格低廉,可重复率高并且容易被妊娠妇女接受等优点。近年来许多研究证实,妊娠早期FPG与葡萄糖负荷试验(glucose challenge test,GCT)及口服葡萄糖耐量试验(oral glucose tolerance test,OGTT)的血糖水平呈正相关,且显著降低了需要行OGTT检查的人数。故FPG筛查对GDM有较高的价值。     

Physiology and clinical value of glycosuria after a glucose challenge during pregnancy

Objective

Urine testing for glucose is commonly performed during pregnancy but little is known about the regulation and clinical value of glycosuria because studies are hampered by its low prevalence and intermittent nature. The aim of this study was to compare the urine and plasma response 60 min after a 50 g oral glucose challenge in the setting of gestational diabetes mellitus (GDM) screening.

Study design

Of 338 consecutively enrolled gravidas, 325 completed the study. Glycosuria was measured semi-quantitatively (0, 1, 2 or 3+) and venous plasma glucose was measured.

Results

Post-challenge glycosuria occurred in 26.2% of gravidas. Women with 2 or 3+ glycosuria showed higher plasma glucose (p < 0.001), lower height (p = 0.004) and lower body weight throughout pregnancy (p = 0.014); however, glycosuria was not related to age, parity, body mass index (BMI), highest blood pressure or newborn size at birth. The sensitivity for a GDM diagnosis was 8.2%. Comparison of pure “urine” responders (i.e., any glycosuria but glucose <130 mg/dl, n = 50) with “plasma” responders (no glycosuria but plasma glucose ≥140 mg/dl, n = 29) showed that urine responders were younger and had a lower body weight and BMI than plasma responders.

Conclusion

Glycosuria after an oral glucose challenge depends on the plasma glucose excursion, and is more pronounced in gravidas with lower height and body weight, who presumably have a smaller plasma distribution volume. Post-load glycosuria is a poor predictor of GDM, pre-eclampsia and newborn size at birth, and therefore has limited clinical benefit.