Early-pregnancy glucose screening for gestational diabetes mellitus

OBJECTIVE: To determine the accuracy of the 50-g, one-hour glucose screening test administered at 16 weeks of pregnancy for identifying women with gestational diabetes mellitus. STUDY DESIGN: Two hundred fifty-five women underwent 50-g, one-hour glucose screening tests at 16 weeks of pregnancy. Those with results > or = 135 mg/dL underwent 100-g, three-hour glucose tolerance tests. All patients without diagnoses of gestational diabetes during the second trimester of pregnancy underwent standard third-trimester glucose testing. RESULTS: Gestational diabetes mellitus was diagnosed in 25 patients. Glucose screening tests administered at 16 weeks of pregnancy identified 96% (24) of these patients. Patients with 16-week glucose screening test results > or = 135 mg/dL had a 55% risk of developing diabetes during pregnancy, while the risk was 0.6% for patients with 16-week test results < or = 110 mg/dL. Patients with 16-week glucose screening test results in the intermediate range, 111-134 mg/dL, had a 4.8% risk of developing diabetes during pregnancy. CONCLUSION: Glucose screening at 16 weeks of pregnancy is a useful alternative to third-trimester screening for gestational diabetes. The negative predictive value of screening test results < or = 110 mg/dL is 99.4%. The positive predictive value for screening test results > or = 135 mg/dL is 55%. This latter finding is superior to the 8.6-22% found during the third-trimester.     

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.     

Gestational diabetes. Is a 50-g screening result > or = 200 mg/dL diagnostic?

OBJECTIVE: To evaluate the diagnosis of gestational diabetes based on a 50-g, one-hour glucose screening test result > or = 200 mg/dL. STUDY DESIGN: Retrospective ascertainment of pregnant women who had a 50-g, one-hour glucose screening test result > or = 200 mg/dL was performed among prenatal care registrants. The diagnosis of gestational diabetes was determined by 100-g, three-hour oral glucose tolerance test (GTT) results and/or repeated fasting serum glucose measures. RESULTS: In 1995, 69 women were referred to the gestational diabetes clinic with a 50-g result > or = 200 mg/dL. Four women could not be classified, two had pregestational glucose intolerance and four charts were unavailable. Of the remaining 59 women, 11 (19%) had normal three-hour GTTs, and 48 (81%) were diagnosed with gestational diabetes (35 [59%], A1; 13 [22%], A2). There was one large-for-gestational-age (LGA) infant born in the nondiabetic group (9%), 13 LGA infants born in the A1 group (37%) and 6 LGA infants born to the A2 diabetics (46%). The relationship between maternal diagnosis and LGA outcome was statistically significant. CONCLUSION: A 50-g screening test result > or = 200 mg/dL is not diagnostic of gestational diabetes. Nearly one of five such women had a normal three-hour oral GTT. Overdiagnosis of gestational diabetes may lead to unnecessary pregnancy surveillance and intervention.     

Gestational diabetes: comparision of the carpenter and the coustan thresholds with the new thresholds of Turkish women and implications of variations in diagnostic criteria

Objective: To find optimal 100-g 3-h oral glucose tolerance test (OGTT) threshold levels for diagnosis of gestational diabetes (GDM) in Turkish pregnant women. Methods: This study was conducted with 808 women screened for GDM between 24–28 weeks of gestation using the 1-h 50-g glucose challenge test (GCT) with a subsequent 3-h 100-g OGTT for confirmation if screen was positive. The glucose values obtained were analysed by both the Carpenter and Coustan (C&C criteria) and National Diabetes Data Group (NDDG) criteria for the diagnosis of GDM and IGT. Optimal OGTT cutoff values for Turkish population were calculated by ROC curve analysis. Results: The new diagnostic criteria, based on the result of the 100-g OGTT obtained from the healthy pregnant women, were 82.5, 171.5, 151.5, and 111.5?mg/dl at 0, 1, 2, and 3?h. The prevalence of GDM was 15.7% by the new criteria, 8.1% by C&C criteria, and 5.6% by the NDDG criteria. According to new criteria, 7.7% of infants of diabetic mothers had macrosomia. This ratio was 2.6% for non diabetic women. Conclusions: Ethnic differences, enviromental factors and nutritional habits may effect development of GDM. Application of some pre-determined nomograms to all races and ethnic groups can lead errors.     

Screening for gestational diabetes in Sicily.

OBJECTIVE: To establish the prevalence of gestational diabetes in a universally screened population living in Messina, Sicily, as the first step in evaluating the cost: benefit ratio of screening for carbohydrate intolerance in pregnancy. STUDY DESIGN: Between October 1989 and March 1995, 1,000 pregnant women underwent screening for gestational diabetes with a 50-g, one-hour glucose challenge test. All the risk factors were registered. RESULTS: Two hundred sixty subjects had a value of > or = 135 mg/dL and underwent a full three-hour oral glucose tolerance test. Of them, 46 (4.6%) met the Carpenter-Coustan diagnostic criteria for gestational diabetes. CONCLUSION: The apparent incidence of gestational diabetes (1.2%) prior to screening was only 25% of the incidence determined with the protocol of universal screening (4.6%). If we assume that timely diagnosis and treatment of gestational diabetes provides an important opportunity to improve obstetric outcome and reduce perinatal morbidity, and since women with gestational diabetes are at increased risk of developing diabetes later, the knowledge that the true prevalence is almost four times that previously reported is a determinant of a future evaluation of the cost:benefit ratio of screening universally for gestational diabetes.     

Abnormal glucose screening tests in pregnancy: a risk factor for fetal macrosomia

Of 2276 patients who underwent screening for gestational diabetes mellitus, 1854 (81.5%) had normal glucose screening tests after a 50-g carbohydrate load (serum glucose below 135 mg/dL). Three hundred fifty-seven patients (15.7%) had abnormal glucose screening tests and went on to complete three-hour glucose tolerance tests, of whom 176 (48.7%) were shown to be nondiabetic when further tested using a carbohydrate-loaded, 100-g glucose, three-hour glucose tolerance test. The 176 women with abnormal glucose screens but normal glucose tolerance tests were compared with the 1854 who had normal screening values. The frequency of infants weighing more than 4000 g (greater than 95th percentile at our institution) was 11.9% in the study group and 6.4% in the control group (P = .0086). When the data were corrected for other macrosomia risk factors (advanced age, high parity, obesity, white race, and prolonged gestation), there was still a significantly higher frequency of macrosomia in the study group; this fact suggests that patients with minor abnormalities of carbohydrate metabolism during pregnancy are at risk for delivering a macrosomic infant.     

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.     

Gestational diabetes mellitus in Chinese women.

OBJECTIVE: To determine whether foreign diagnostic criteria for the diagnosis of gestational diabetes mellitus (GDM) are suitable for Chinese pregnant women. METHODS: The study participants were 340 pregnant women receiving obstetric care at the Shanghai Jiaotong University-Affiliated Sixth People's Hospital in Shanghai, China. The normal-pregnancy group comprised 190 women with no risk factor for GDM and the high-risk pregnancy group comprised 150 women who had at least one high-risk factor for GDM. All women took the diagnostic 100-g, 3-h oral glucose tolerance test (100-g 3-h OGTT) between 24 and 28 weeks of pregnancy. The results of the 100-g 3-h OGTT were classified according to three different sets of diagnostic criteria: (1) new, "Chinese" diagnostic criteria based on the results from the 100-g 3-h OGTT performed in the 190 healthy participating women; (2) the Carpenter and Coustan criteria; and (3) the National Diabetes Data Group (NDDG) criteria. Venous plasma glucose (VPG) was measured by the glucose oxidase method. A consistency check was used for analysis. Obstetric and neonatal outcomes were recorded. RESULTS: With 97.5% as the statistical cutoff value for the 100-g 3-h OGTT, the new diagnostic criteria for this study, based on data obtained from the 100-g 3-h OGTT performed on the 190 participating healthy pregnant women, were 5.2, 10.3, 8.9, and 7.7 mmol/L at 0, 60, 120, and 180 min. The e value was 0.83 for the new criteria vs. the Carpenter and Coustan criteria (P<0.001) and 0.70 for the new criteria vs. the NDDG criteria (P<0.001). In women with GDM and gestational-impaired glucose tolerance (GIGT), the incidence rates of macrosomia by the new criteria and the Carpenter and Coustan criteria were similar, but higher than the rates calculated with the NDDG criteria (P<0.05). CONCLUSION: With venous plasma glucose level measured by the glucose oxidase method, the Carpenter and Coustan criteria are applicable to Chinese pregnant women for diagnosis of GDM.     

Gestational diabetes screening in subsequent pregnancies of previously healthy patients

OBJECTIVE: Our purpose was to evaluate women without gestational diabetes mellitus in an index pregnancy for the likelihood that gestational diabetes would develop and for risk factors for carbohydrate intolerance in a subsequent pregnancy.Study Design: A retrospective review of medical records at a teaching hospital universally screening for gestational diabetes identified multiparous women who had been delivered twice between 1994 and 1997 and who, in the first (index) pregnancy, had had a normal result on a screening test with 50 g of glucose used in a "glucola" beverage (< or =140 mg/dL). RESULTS: In this population with normal glucose screening values in the index pregnancy, 352 (92.4%) of 381 women had at least one risk factor for gestational diabetes. However, none of the 381 women had gestational diabetes in the subsequent pregnancy (0/381, 95% confidence interval < or =1%), including 45 (12. 4%) who had an abnormal result on the 50-g glucose screening test. Regression analysis showed this test result in the index pregnancy (P =.001) to be the only studied variable significantly associated with the 50-g glucose value in the subsequent pregnancy. CONCLUSION: Despite a high rate of risk factors for gestational diabetes, women in our population with a normal glucose value in an index pregnancy have a minimal risk (<1%) that gestational diabetes will develop in a subsequent singleton pregnancy within 4 years. This factor may be included in determining whether women should undergo screening for gestational diabetes.     

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     

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.     

Could the fasting plasma glucose assay be used to screen for gestational diabetes?

The fasting plasma glucose assay was compared with the one-hour post-glucose test as a screening test for identification of gestational diabetes. Of 4,561 consecutive patients screened with a 50-g glucose test, 968 (21.2%) had results > or = 135 mg/dL; 141 (14.6%, or 3.1% of the total) were found to have diabetes. In the 968 patients, the area under the fasting plasma glucose receiver operating characteristic curve was greater than that under the glucose screening test curve, indicating greater discriminatory value of the former test. Of the 116 patients who had sequential glucose screening tests and fasting plasma glucose assays performed twice during pregnancy, a significant correlation was found for fasting plasma glucose values, but not for glucose screening test values. We conclude that the fasting plasma glucose assay may perform better than the one-hour post-glucose test as a screening test for gestational diabetes. Based on these data, a population-based prospective study seems justified.     

Hypoglycemia during the 100-g oral glucose tolerance test: incidence and perinatal significance

OBJECTIVE: To estimate and report the incidence and perinatal significance of hypoglycemia during the 100-g oral glucose tolerance test in pregnant women. METHODS: Over a 3-year period, we analyzed the incidence and perinatal outcome of pregnant women who experienced hypoglycemia, defined as a plasma glucose level of 50 mg/dL or less while undergoing the 100-g oral glucose tolerance test. The study group included women who delivered singletons at term. Women who underwent the 100-g oral glucose tolerance test during the same period and had no hypoglycemia served as the control group. RESULTS: A total of 805 women were included in the study, which comprised 51 women (6.3%) who experienced hypoglycemia during the test and 754 women in the control group. Gestational diabetes mellitus was diagnosed in 5/51 (9.8%) women in the study group, compared with 216/754 (28.6%) women in the control group (P < .03), and the neonates born to these women had significantly lower birth weights. CONCLUSION: The incidence of reactive hypoglycemia during the 100-g oral glucose tolerance test in our population is 6.3%. Women who experience hypoglycemia during the test have a significantly lower incidence of gestational diabetes and neonatal birth weights.     

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.     

Impaired glucose tolerance associated with adverse pregnancy outcome: a population-based study in southern Sweden

OBJECTIVE: We conducted a population-based study of maternal and neonatal characteristics and delivery complications in relation to the outcome of a 75-g, 2-hour oral glucose tolerance test at 25 to 30 weeks' gestation. STUDY DESIGN: An oral glucose tolerance test was offered to pregnant women in a geographically defined population. Pregnancy outcome was analyzed according to the test result. RESULTS: Among women delivered at Lund Hospital, we identified 4526 women with an oral glucose tolerance value of <7.8 mmol/L (<140 mg/dL), 131 women with a value of 7.8 to 8.9 mmol/L (140-162 mg/dL), and 116 women with gestational diabetes (> or =9.0 mmol/L [> or =162 mg/dL]). A further 28 cases of gestational diabetes were identified, giving a prevalence of 1.2%. An increased rate of cesarean delivery and infant macrosomia was observed in the group with a glucose tolerance value of 7.8 to 8.9 mmol/L (140-162 mg/dL) and in the gestational diabetes group. Advanced maternal age and high body mass index were risk factors for increased oral glucose tolerance values in 12,657 screened women in the area. CONCLUSION: The study stresses the significance of moderately increased oral glucose tolerance values.     

Are patients with positive screening but negative diagnostic test for gestational diabetes under risk for adverse pregnancy outcome?

OBJECTIVE: Our aim was to determine the obstetrics outcomes of patients with positive 1-h glucose challenge test (GCT), but negative diagnostic test for gestational diabetes. METHODS: Pregnancy records of 409 pregnants were reviewed. Patients were screened for gestational diabetes mellitus (GDM) with one-hour 50 g glucose challenge test (GCT) at 24-28 weeks of gestation. Patients with glucose challenge tests values > or = 130 mg/dL were refered for the 3 h, 100-g oral glucose tolerance test (OGTT). Positive GCT but negative for OGTT group (Group A) were compared retrospectively with the group of negative GCT (Group B) for obstetrics outcomes. RESULT: GDM and impared glucose tolerance (IGT) were diagnosed in 33 (7.6%) and 46 (10.5%) patients, respectively. We identified 141 (34.4%) patients with positive GCT but negative for OGTT (Group A) and 189 (46.2%) patients with negative GCT (Group B). Gestational weight gain, polyhydramnios, family history of diabetes mellitus were significantly higher in group A than group B (P < 0.05). Prevalance of preterm labor, hypertension, cesarean delivery, mean birthweight, proportion of babies admitted to neonatal intensive care unit were similar in both groups. CONCLUSION: There are some differences for pregnancy outcomes between pregnants with positive GCT but negative for OGTT and negative GCT. These patients should be followed up carefully during the antepartum and intrapartum period.     

Effect of hyperprolactinemia on the androgen response to an oral glucose load.

OBJECTIVE: To investigate the effect of hyperprolactinemia on the androgen response to an oral glucose load in patients with normal and abnormal carbohydrate metabolism. DESIGN: Sixty-three women underwent a 75-g oral glucose tolerance test (OGTT) at approximately 6 weeks' postpartum. SETTING: University hospital setting. PATIENTS: Patients with a previous history of gestational diabetes. MAIN OUTCOME MEASURE: Adrenal and ovarian androgen response to oral glucose load. RESULTS: Results were stratified by the result of the OGTT (patients with impaired glucose tolerance or diabetes as a single group and patients with a normal OGTT as a separate group) and prolactin (PRL) level. All androgens decreased significantly over the 2-hour test in all groups except dehydroepiandrosterone sulfate (DHEAS) in the patients with both elevated PRL and abnormal glucose tolerance. CONCLUSION: Hyperprolactinemia and insulin resistance may act synergistically in the adrenal to alter DHEAS suppression and may result in chronically elevated circulating DHEAS levels.     

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.     

Correlation between one-hour, 50-g glucose screening values in successive pregnancies

OBJECTIVE: To investigate the relationship between one-hour, 50-g oral glucose screening test results in successive pregnancies and to assess the risk of gestational diabetes in women who had a previously negative glucose screening test during a prior pregnancy. STUDY DESIGN: Sixty-nine women were studied who had successive pregnancies delivered at intervals ranging from one to four years. All had glucose screening tests performed at 24-32 weeks of gestation during both pregnancies. The relationship between glucose screening test results was examined for interpregnancy intervals of up to two, three and four years. RESULTS: The correlation for interpregnancy glucose screening test results was .60, .49 and .47 for pregnancy intervals of up to two, three and four years, respectively (P < .001). The mean glucose screening test result was 108 +/- 23 mg/dL for prior pregnancies and 104 +/- 21 mg/dL for subsequent pregnancies (no significant difference). A screening test result > or = 140 mg/dL occurred in 1.6% of cases in which a previous test result was < 140 mg/dL during a prior pregnancy. CONCLUSION: A glucose screening test result of < 140 mg/dL during pregnancy is strongly predictive of a subsequent negative screening test result in a succeeding pregnancy when it occurs within four years. Under such circumstances, the risk of gestational diabetes during a subsequent pregnancy is reduced by 85-95% to no more than 0.3%.     

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.