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.     

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.     

Screening for gestational diabetes mellitus in the subsequent pregnancy: is it worthwhile?

OBJECTIVE: The purpose of this study was to determine, among women without evidence of gestational diabetes mellitus during their first pregnancy, the likelihood of, and associated risk factors for, the development of gestational diabetes mellitus in the subsequent pregnancy. STUDY DESIGN: This was a retrospective cohort study, with a time frame of 1991 to 1999. RESULTS: Of 3710 women without gestational diabetes mellitus in the first pregnancy, 1% (37 women) were subsequently diagnosed with gestational diabetes mellitus in the second pregnancy. These 37 women, when compared (by means) to women without gestational diabetes mellitus in their second pregnancy, were more likely to be older (age 21 years vs 19 years) and obese (first visit body mass index, 28 kg/m(2) vs 25 kg/m(2)) and to have an interpregnancy weight gain of >5 kg (93% vs 49%) and a longer mean interpregnancy interval (33 months vs 24 months). Regression analysis revealed that, during the first pregnancy, a first visit body mass index of >29 kg/m(2) (odds ratio, 2.2; 95% CI, 1.1-4.5) and a serum glucose screen of >101 mg/dL (odds ratio, 8.3; 95% CI, 2.5-27.9) were associated significantly with the development of gestational diabetes mellitus in the second pregnancy, as was an interpregnancy weight gain of >5 kg (odds ratio, 10.8; 95% CI, 2.5-46.3). All women who subsequently had gestational diabetes mellitus had at least one of these risk factors. CONCLUSION: Among women without gestational diabetes mellitus in the first pregnancy, the risk of gestational diabetes mellitus in a second pregnancy is low. Therefore, screening all such women in the second pregnancy may not be justified.     

Gestational diabetes mellitus and lesser degrees of pregnancy hyperglycemia: association with increased risk of spontaneous preterm birth

OBJECTIVE: To investigate whether different degrees of maternal glucose intolerance are associated with the risk of spontaneous preterm birth. METHODS: We performed a cohort study of 46,230 pregnancies screened by a 50-g, 1-hour oral glucose tolerance test between 24 and 28 gestation weeks at the Northern California Kaiser Permanente Medical Care Program. Spontaneous preterm birth was defined as an infant born at less than 37 gestation weeks with at least one of the following: spontaneous labor, preterm premature rupture of membranes, or incompetent cervix. Glucose tolerance status was categorized as normal screening (1-hour plasma glucose less than 140 mg/dL), abnormal screening (1-hour plasma glucose of at least 140 mg/dL with a normal diagnostic 100-g, 3-hour oral glucose tolerance test result), Carpenter-Coustan (plasma glucose measurements during the diagnostic oral glucose tolerance test met the thresholds but were lower than the National Diabetes Data Group thresholds), and gestational diabetes mellitus (GDM) by the National Diabetes Data Group criteria. RESULTS: One thousand nine hundred fifty-six spontaneous preterm births occurred. Age-adjusted incidences of spontaneous preterm birth were 4.0% in normal screening, 5.0% in abnormal screening, 6.7% in Carpenter-Coustan, and 6.7% in GDM. In a logistic regression model adjusted for age, race-ethnicity, preeclampsia-eclampsia-pregnancy-induced hypertension, chronic hypertension, polyhydramnios, and birth weight for gestational age, pregnancies with abnormal screening, Carpenter-Coustan, and GDM had a significantly higher risk of spontaneous preterm birth than pregnancies with normal screening (relative risk [95% confidence interval]: 1.23 [1.08, 1.41], 1.53 [1.16, 2.03], and 1.42 [1.15-1.77], respectively). CONCLUSION: The risk of spontaneous preterm birth increased with increasing levels of pregnancy glycemia. This association was independent of perinatal complications that could have triggered early delivery.     

Correlation between first- and early third-trimester glucose screening test results

One hundred twenty-four normal gravidas had paired first- and early third-trimester (26-32 weeks) 1-hour oral glucose screening tests performed. First-trimester oral glucose screening test values correlated significantly with third-trimester glucose screening test results for the entire population, for whites and non-whites, and for normal-weight and obese patients. First-trimester oral glucose screening test values at or below 110 mg/dL were seldom associated with third-trimester oral glucose screening test results at or above 135 mg/dL and were not associated with abnormal 3-hour glucose tolerance test (GTT) results. Nine of the gravidas (7.3%) were diagnosed with gestational diabetes mellitus during the third trimester, all of whom had first-trimester glucose screening test results above 110 mg/dL. The difference in incidence of gestational diabetes mellitus between gravidas having first-trimester glucose screening test results at or below 110 mg/dL (0%) and those having values above 110 mg/dL (16.4%) was highly significant (P less than .0001). For patients with first-trimester glucose screening test values at or below 110 mg/dL, third-trimester glucose screening may be unnecessary. In contrast, for gravidas having first-trimester glucose screening test results at or above 135 mg/dL, there is a high positive predictive value for elevated repeat glucose screening test results during the early third trimester. Patients having elevated first-trimester glucose screening values at or above 140 mg/dL are at particularly high risk for elevated glucose screening test results later in pregnancy and should forego repeat 1-hour third-trimester glucose screening in favor of a direct third-trimester 3-hour GTT.     

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.     

Serial changes in the 50-g oral glucose test in pregnancy: implications for screening

To quantitate the effect of advancing pregnancy on the screening test for gestational diabetes, 550 patients were given a 50-g oral glucose screening test at 20, 28, and 34 weeks' gestation. A significant increase in the plasma glucose value was found, with a mean increase of 1.1 +/- 1.9 mg/dL per week from 20-34 weeks' gestation (r = 0.39, P less than .01). Only 34 patients (6.2%) had a positive screening test at 20 weeks' gestation, and it appears that routine screening in a low-risk population at 20 weeks is not warranted. Sixty patients (10.9%) with a negative screening test at 20 weeks had a positive test at 28 weeks. Forty-four patients (8.0%) with a negative test at 28 weeks had a subsequent positive test at 34 weeks. The overall incidence of gestational diabetes in this population was 4.9%. Currently, screening is recommended at 24-28 weeks for all pregnancies that have not been previously identified as having glucose intolerance. Eleven percent of the gestational diabetics in our population would have been undetected had we screened only at 24-28 weeks. This quantitative information may be helpful in deciding whether rescreening later in pregnancy is indicated.     

Effect of fetal hyperinsulinism on oral glucose tolerance test results in patients with gestational diabetes mellitus

OBJECTIVE: This study was undertaken to evaluate the impact of the fetoplacental glucose steal phenomenon on the results of oral glucose tolerance testing in pregnancies complicated by gestational diabetes mellitus with fetal hyperinsulinism. STUDY DESIGN: This was an analysis of the cases of 34 patients with two consecutive abnormal oral glucose tolerance test results and amniotic fluid insulin measurement before institution of insulin therapy. Patients were divided into groups on the basis of normal versus elevated amniotic fluid insulin concentrations. RESULTS: Oral glucose tolerance tests were done at a mean (+/-SD) of 24.9 +/- 5.7 and 30.7 +/- 3.2 weeks' gestation, and amniotic fluid insulin measurements were done at 31.1 +/- 3.2 weeks' gestation. In 13 women with gestational diabetes mellitus with normal amniotic fluid insulin concentration, maternal postload blood glucose levels at 1 hour increased by 12 mg/dL (168 vs 180 mg/dL; 9.3 vs 10.0 mmol/L; P = .0006) during the course of 6 weeks. In contrast, in 21 women with gestational diabetes mellitus with elevated amniotic fluid insulin levels (>7 microU/mL; >42 pmol/L), 1-hour postload blood glucose levels decreased by 22 mg/dL (201 vs 179 mg/dL; 11.2 vs 9.9 mmol/L; P = .002) during the same period. The higher the amniotic fluid insulin level, the larger the decrease (R = 0.504; P =.02). Although low amniotic fluid insulin levels were correlated significantly with 1-hour glucose levels of the first and second oral glucose tolerance tests, high insulin levels were no longer correlated with the second oral glucose tolerance test. CONCLUSION: Exaggerated fetal glucose siphoning may provide misleading oral glucose tolerance test results in pregnancies complicated by fetal hyperinsulinism by blunting maternal postload glucose peaks. Consequently, oral glucose tolerance test results in a pregnancy complicated by gestational diabetes mellitus with a fetus that already has hyperinsulinemia may erroneously be considered normal.     

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.     

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.     

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.     

Fasting plasma glucose test at the first prenatal visit as a screen for gestational diabetes

OBJECTIVE: To determine whether the fasting plasma glucose test administered at the first prenatal visit could serve as an efficient screen for gestational diabetes. METHODS: A total of 5557 women not known to have diabetes were offered a fasting plasma glucose test at their first prenatal visit. Results less than 100 mg/dL were blinded. A glucose tolerance test was requested immediately of those whose screening test result was 100-125 mg/dL and of all women not identified as having diabetes by their 23rd gestational week. RESULTS: A total of 4507 women (81%) complied with the protocol. Of the 302 women found to have gestational diabetes, 46 (15%) were detected before 24 weeks. A false-positive rate of 57% was found at a threshold fasting glucose concentration giving a sensitivity of 80% for the detection of gestational diabetes.CONCLUSION: The fasting plasma glucose screening test at the first prenatal visit has good patient compliance. However, its poor specificity (high false-positive rate) makes it an inefficient screening test for gestational diabetes.     

Screening recommendations for gestational diabetes mellitus

As a result of extensive experiences in multiple centers and a review of the current literature, we conclude that a plasma glucose level obtained 1 hour after a 50 gm oral glucose challenge is the "best" gestational diabetes mellitus screening test. This universal screening is performed at least once during pregnancy. The screening threshold should be no higher than 140 mg/dl, or an unacceptable loss in sensitivity occurs. Universal screening for gestational diabetes mellitus is justified by morbidity reduction, cost, and protocol simplicity and ease.     

Cost-effective criteria for glucose screening

To study cost-effective screening criteria for gestational diabetes, a prospective study of 1012 patients was completed. All patients underwent a glucose screen between 26 and 30 weeks of gestation, consisting of a 50-g oral glucose load followed by a one-hour plasma glucose determination. Patients with a glucose screen greater than or equal to 130 mg/dL were studied with a standard three-hour oral glucose tolerance test. The incidence of gestational diabetes was 2.4% (24 of 1012). Only one gestational diabetic was identified with a glucose screen below 150 mg/dL. Twenty-two of the 24 cases were at least 24 years old. Twenty-one of the 24 (88%) gestational diabetes had a glucose screen greater than or equal to 150 mg/dL and were 24 years old or greater. The cost of the diagnosis in these latter patients was 40% of the cost of diagnosis of universal screening with a threshold of 130 mg/dL. It is concluded that screening with a threshold of 150 mg/dL only patients who are at least 24 years old should be considered an alternative to universal screening.     

Predictive factors of developing diabetes mellitus in women with gestational diabetes

BACKGROUND: To investigate which factors during gestational diabetes pregnancies correlate with the risk of developing impaired glucose tolerance or diabetes 1 year postpartum and to compare this risk in women with gestational diabetes and women with a normal oral glucose tolerance test during pregnancy. METHODS: Of 315 women with gestational diabetes, defined as a 2-hr blood glucose value of at least 9.0 mmol/l at a 75-g oral glucose tolerance test, who delivered in Lund 1991-99, 229 (73%) performed a new test 1 year postpartum. We compared maternal and fetal factors during pregnancy with the test value at follow up. A control group of 153 women with a 2-hr test value below 7.8 mmol/l during pregnancy were invited to a new test 1 year postpartum and 60 (39%) accepted. RESULTS: At 1 year follow up, 31% of the women with gestational diabetes but only one of the 60 controls showed pathologic glucose tolerance and one had developed diabetes. The following factors in women with gestational diabetes were identified as predicting impaired glucose tolerance or diabetes at 1 year follow up: maternal age over 40 and--in a multiple regression analysis, independent of each other--a high 2-hr value at oral glucose tolerance test during pregnancy and insulin treatment during pregnancy. CONCLUSION: The risk of developing manifest diabetes after gestational diabetes may be high enough to justify a general screening or diagnostic procedure in all pregnant women to identify women with gestational diabetes and a postpartum follow up program for them. This study did not identify any particular factor during pregnancy with enough precision to predict a later progression to diabetes.     

Results of screening tests for gestational diabetes mellitus at Medical University in Warsaw

Our purpose was to determine the incidence of screening for gestational diabetes among the population of women delivering at I and II Departments of the First Faculty of Medical University in Warsaw. A retrospective review of 647 pregnancies was performed. The incidence of gestational diabetes mellitus screening was determined and the rate of occurrence of GDM analyzed. 310 (48%) pregnancies were screened for gestational diabetes mellitus with a 1-hour, 50 gm oral glucose challenge test. 49 (16.07%) of the screens had positive results at a plasma glucose level of > 139 mg/dl. Two-hour 75 gm oral glucose tolerance tests (according to the 1994 World Health Organization panel recommendations) were performed on screen-positive women, eleven of whom (22.45%) were diagnosed with gestational diabetes mellitus. Despite of positive oral 50 gm glucose test, (plasma glucose level 140-179 mg/l) 15 women (30%) haven't had the 75 gm oral glucose test. The incidence of GDM among analyzed population is 4% and when GDM screening is carried out, exceeds 7%. Early gestational glucose screening, if performed, may be beneficial in detecting gestational diabetes. Consideration should be given to fulfill it more frequently and for sure, repeat glucose testing in patients with positive one-hour screening tests.     

Clinical predictors for a high risk for the development of diabetes mellitus in the early puerperium in women with recent gestational diabetes mellitus

OBJECTIVE: The purpose of this study was to identify which maternal, antepartum, or neonatal clinical parameters were predictive for a high risk of diabetes mellitus in the puerperium in women with recent gestational diabetes mellitus and to calculate the associated diabetes mellitus rates and odds ratios. STUDY DESIGN: One thousand six hundred thirty-six women underwent an oral glucose tolerance test within 1 to 4 months of delivery. Demographic, historic, and antenatal glycemic parameters and neonatal outcome parameters were tested by univariate and multivariate logistic regression for risk of postpartum diabetes mellitus. Continuous variables were divided into quartiles that compared the upper to lower quartile adjusted odds ratio and prevalence of diabetes mellitus. RESULTS: Postpartum diabetes mellitus was diagnosed in 230 women (14.1%) according to the American Diabetes Association criteria (1997). No maternal demographic or neonatal parameters were significantly associated with diabetes mellitus. The final model of independent predictors in decreasing significance included the highest fasting plasma glucose level during pregnancy, any fasting plasma glucose level of > or = 105 mg/dL (class A(2)), the area under the curve of pregnancy oral glucose tolerance test, gestational age at diagnosis, previous gestational diabetes mellitus history, and 50-g glucose challenge test results. The fasting plasma glucose level was the best discriminator, with a 21-fold (95% CI, 4.6-96.3) increased odds ratio comparing the 4th quartile (fasting plasma glucose level, >121 mg/dL; diabetes mellitus rate, 36.7%) to 1st quartile (fasting plasma glucose level, < 95 mg/dL; diabetes mellitus rate, 0.5%). The presence of previous gestational diabetes mellitus or current class A(2) gestational diabetes mellitus approximately doubled the odds ratio for diabetes mellitus. The odds ratio increased 3- to 4-fold when the area under the curve was > or = 33.36 min small middle dot g/dL (4th quartile) or the glucose challenge test was > or = 155 mg/dL (2nd-4th quartiles) and decreased > 50% if gestational diabetes mellitus was diagnosed at > 27 weeks (3rd-4th quartile). CONCLUSION: During pregnancy, the highest fasting glucose level, followed by the severity of glucose intolerance, and earlier gestational diabetes mellitus diagnosis were the best predictors for postpartum diabetes mellitus. Diabetic education should begin during pregnancy, especially for women who are identified to be at a high risk when they are highly motivated and under medical care.     

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 >or=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 >or=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 >or=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 >or=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 usefulness of glycosuria and the influence of maternal blood pressure in screening for gestational diabetes

OBJECTIVE: Although gestational diabetes is among the most common diseases arising during pregnancy, glucose stix is the only screening test to date in Germany. Our goal was to evaluate the sensitivity of the glucose-stix for diabetes screening and the possible influence of other parameters. METHODS: 1001 patients who underwent the 50 g glucose screening test between June 1, 1997 and January 5, 2000 as part of prenatal care were asked to participate. In accordance with the guidelines of the American Diabetes Association, patients with a screening test result >/= 140 mg/dl underwent a oral glucose tolerance test (Carpenter/Coustan criteria). A urine sample was collected prior to the test. The glucose content of the urine was semiquantitatively analyzed using a test strip (Multistix 10 SG Bayer), Munich, Germany). Blood pressure was measured in 349 consecutive cases according to the criteria of the National Institute of Health. RESULTS: The overall frequency of gestational diabetes was 4.1% (37/912). 8.2% of the women presented with glycosuria (82/1001, 36 before screening, 46 based on the pregnancy medical records booklet). 30/82 (37%) of these patients had a pathological screening test (P = 0.029). 7.1% (52/729) of the healthy patients and 10.8% (4/37) of the gestational diabetics had glycosuria at least once. Therefore, the sensitivity of glycosuria is 10.8%, the positive predictive value is 6.6%. The systolic blood pressure was 116+/- 12 mmHg and the diastolic blood pressure 72 +/- 9 mmHg. Three of 349 (0.9%) patients were documented with preexisting hypertension, 14/349 (4.0%) patients with "pregnancy induced hypertension". Patients with glycosuria were both significantly more advanced in gestational age (34.4 +/- 2.8 versus 33.7 +/- 2.9, P = 0.673) and had higher diastolic blood pressure (79 +/- 9 versus 71 +/- 9, P = 0.005). The 50 g glucose screening test results showed only a tendency to differ (131 +/- 23 versus 127 +/- 24, P = 0.073). A multivariate analysis of these factors showed a significant influence of the diastolic blood pressure (P = 0.016) and the 50 g glucose screening test (P = 0.032), whereas the gestational week had no influence (P = 0.673). CONCLUSIONS: Urine glucose dip stick analysis is not useful in the detection of gestational diabetes because of its low sensitivity and negative predictive value. Our study suggests that glycosuria is not only dependent on the blood glucose level, but highly influenced by diastolic blood pressure. The results clearly underscore the need for standardized, routine testing of every pregnant woman.     

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