Abnormal Glucose Challenge Test Research Articles

Utilizing the glucose challenge test during pregnancy as a predictor of future diabetes risk

BackgroundGestational Diabetes Mellitus (GDM) presents a significant health concern during pregnancy, predisposing individuals to future diabetes. Despite established postpartum diabetes screening guidelines, adherence to follow-up remains inadequate.AimsThis study aimed to assess the predictive value of the 50-gram glucose challenge test (GCT) for post-pregnancy diabetes development.Materials and methodsA population-based retrospective cohort study was conducted on pregnant women aged 18–45 who underwent GCT screening between November 2007 and July 2017 in a large Israeli community medical organization. Baseline characteristics, GCT results, and diabetes development during follow-up were analyzed using univariate and multivariate Cox regression analyses.ResultsAmong 8,675 women included, 2.4% developed diabetes over a median follow-up of 73.23 months. Elevated GCT results correlated with a higher risk of future diabetes, with a 4% rise in risk per 1 mg/dL increase in glucose above 140 mg/dL. Multivariate analysis revealed a 60-fold rise in the risk of future diabetes in women with GCT results ≥ 200 mg/dL compared to those with GCT < 140 mg/dL, adjusting for age, body mass index, pre-pregnancy glucose, cholesterol, and triglycerides. A GCT result between 140 and 199 mg/dL was a predictor of future diabetes, even when adjusted for GDM based on a subsequent GTT if performed.ConclusionsGCT results during pregnancy strongly predict future diabetes development, with higher GCT values significantly increasing risk. Recognizing abnormal GCT results as indicative of a prediabetic state offers a practical approach for risk stratification, facilitating early diagnosis, and intervention in post-pregnancy care.

Does the gestational age at which the glucose challenge test (GCT) is conducted influence the diagnosis of gestational diabetes mellitus (GDM)?

This study's objective is to investigate disparities in the rates of gestational diabetes mellitus (GDM) diagnosis, influenced by the timing of the glucose challenge test GCT. This retrospective cohort study included women with singleton or twin pregnancies exhibiting abnormal GCT result between 24 and 28 weeks of gestation, followed by an oral glucose tolerance test OGTT during the same period. Data regarding pregnancy follow-up from patients' deliveries at a singular tertiary medical from 2014 to 2022 were retrieved. The probability of GDM diagnosis was stratified based on the gestational week of the GCT and the definition of a positive OGTT, delineated by one or two abnormal values. The study included 636 women with abnormal GCT between 24 and 28weeks of gestation. Of them, 157 unerwent the GCT between 24.0 and 24.6weeks, 204 between 25.0 and 25.6weeks, 147 between 26.0 and 26.6weeks, and 128 between 27.0 and 28.6weeks. We found that the highest incidence of GDM, defined by one or two pathological values of the OGTT, following the initial screening with a GCT, where abnormal results were defined as values exceeding 140mg/dL, was diagnosed in patients who underwent GCT between 26.0 and 26.6weeks of gestation. Conversely, the lowest rates were observed in patients screened between 24.0 and 24.6weeks of gestation. The timing of screening for GDM using the GCT significantly affects the rate of diagnosis. Clinicians managing pregnancies should consider this data when formulating treatment plans.

Prevalance of impaired glucose tolerance and its association with adverse perinatal outcomes in non-gestational diabetes pregnancies

Objective: Gestational diabetes mellitus (GDM) is characterized by glucose intolerance with onset during pregnancy and is one of the most common metabolic disorders complicating pregnancy. The aim of this study was to evaluate the risk of maternal and neonatal outcomes in non-gestational diabetes pregnancies with abnormal glucose challenge test (GCT) and abnormal glucose tolerance test (GTT) results.&#x0D; &#x0D; Methods: In this retrospective cohort study of 2982 singleton pregnancies, all patients underwent a non-fasting 50 g GCT at 24 to 28 weeks of gestation. A GCT cutoff of ≥ 140 mg/dl was selected. Women with an elevated GCT underwent prompt diagnostic testing with a 3-hour GTT. Subjects were divided into four groups according to GCT and GTT results.&#x0D; &#x0D; Results: There was an impaired glucose tolerance in 19.2 % of patients and 14.7 % of them had mild glucose intolerance and 4.5 % of them had moderate glucose intolerance. As expected, there was statistically significant difference in fetal macrosomia, neonatal hypoglicemia, PE, primary CS, and preterm birth between secreening negative and GDM patients (p &lt; 0.0001). We also observed statistically significant difference in neonatal hypoglicemia (p = 0.0001) and PE (p = 0.0277) between screning negative and mild glucose intolerance group. Moreover, there was a significant difference in fetal macrosomia (p=0.0480) between mild glucose intolerance and moderate glucose intolerance groups.&#x0D; &#x0D; Conclusion: Compared with screening negative group, mild and moderate glucose intolerance are associated with increased adverse maternal and neonatal outcomes even in the absence of GDM.

Treatment of Gestational Diabetes Mellitus and Maternal Risk of Diabetes After Pregnancy.

To compare postpartum glucose tolerance between women treated for gestational diabetes mellitus (GDM) and those not treated. Metabolic testing was performed at 3 and 12 months postpartum in 599 women comprising the following gestational glucose tolerance groups: 1) normal glucose challenge test (GCT) and oral glucose tolerance test (OGTT) during pregnancy, 2) abnormal GCT with normal OGTT, 3) gestational impaired glucose tolerance, 4) mild untreated GDM, and 5) severe treated GDM. Birth weight progressively increased across groups 1-4 before falling steeply in treated GDM (P < 0.0001). In contrast, at 3 and 12 months, insulin sensitivity and β-cell function progressively decreased across the five groups, mirrored by rising fasting and 2-h glucose (all P < 0.0001). Accordingly, prevalence of prediabetes/diabetes at 12 months increased in a stepwise manner across groups 1-5 (2.8%, 9.6%, 13.5%, 21.5%, and 32.6%, respectively; P < 0.0001). Treating GDM lowers birth weight but does not disrupt the association between gestational glycemia and maternal prediabetes/diabetes after pregnancy.

Glucose Testing in an Index Pregnancy and Outcomes in a Subsequent Pregnancy: Implications for Screening and a Novel Risk Calculator.

Our objective was to assess whether variables from an index pregnancy (PG1) can be used to guide testing for gestational diabetes mellitus (GDM) in a subsequent pregnancy (PG2) and to create a risk calculator for GDM in PG2. This was a retrospective cohort study of patients delivering ≥2 singleton gestations at >24 weeks' gestation from June 2009 to December 2018, for whom results of a 1-hour glucose challenge test (GCT) were available from PG1. Univariable and multivariable analyses were performed to evaluate factors associated with GDM in PG2. In total, 4,278 patients met the inclusion criteria. Among patients with a normal 1-hour GCT (<140 mg/dL) in PG1 (n = 3,719), 3.9% were diagnosed with GDM in PG2. In multivariable analysis of this group, GDM in PG2 was associated with higher GCT in PG1 (adjusted odds ratio [aOR]: 1.05, 95% confidence interval [CI]: 1.04-1.06), large for gestational age neonate in PG1 (aOR: 1.97, 95% CI: 1.24-3.13), and higher BMI (aOR: 1.08, 95% CI: 1.05-1.11). A novel risk calculator for GDM in PG2 was developed based on these associations. Using a risk cut-off of 15%, the calculator had a positive predictive value of 26% and a negative predictive value of 97%, with 3.2% of patients identified as "at risk". Among patients with abnormal 1-hour GCT in PG1, 38.3% (n = 214/559) had an abnormal 1-hour GCT in PG2 and 34.5% (n = 74/214) of these patients received a diagnosis of GDM. A normal 1-hour GCT in an PG1 is followed by GDM in a subsequent pregnancy in only 3.9% of cases. A novel calculator supports replacing universal screening with targeted testing in subsequent pregnancies in this population. Among patients with an abnormal 1-hour GCT in PG1, nearly 40% have an abnormal 1-hour GCT in a subsequent pregnancy. Direct diagnostic testing can be considered in such patients. · Normal GCT in a first pregnancy is associated with normal GCT in subsequent pregnancy.. · A risk calculator can target diabetes testing in a subsequent pregnancy.. · Abnormal GCT in a first pregnancy is associated with abnormal GCT in subsequent pregnancy..

Glucose Intolerance in Pregnancy and Offspring Obesity in Late Adolescence.

Gestational hyperglycemia is associated with deleterious neonatal outcomes, but long-term risks for offspring obesity are less clear. We estimated the odds for offspring adolescent overweight and obesity among mothers with gestational glucose intolerance. In a mother-offspring historical cohort, the Israel military conscription data set was linked to a large health maintenance organization. Included were women who were evaluated at adolescence and underwent two-step gestational diabetes screening (mean age, 31 years) with a 50-g glucose challenge test (GCT), followed by a 100-g oral glucose tolerance test (OGTT) if the result was abnormal. Glucose tolerance categories included gestational normoglycemia, abnormal GCT with normal OGTT, impaired glucose tolerance (IGT; one abnormal OGTT value), and gestational diabetes. The primary outcome was offspring overweight/obesity (BMI ≥85th percentile) at adolescence, measured prior to military conscription. Logistic regression models were applied. Of 33,482 mother-offspring pairs, overweight and obesity were observed in 6,516 offspring. Across increasing categories of pregnancy glycemia, the proportions of offspring with adolescent overweight/obesity increased: normoglycemia, 19%; abnormal GCT with normal OGTT, 22%; gestational IGT, 24%; and gestational diabetes, 25% (P < 0.0001). Corresponding odds ratios after adjustment for the mother's late adolescent characteristics (sociodemographic confounders and BMI) and pregnancy age were 1.2 (95% CI 1.1-1.4), 1.3 (1.2-1.5), and 1.4 (1.3-1.6), respectively. Further adjustment for offspring birth weight percentile and sociodemographic variables did not materially change results. Associations were more pronounced with increasing obesity severity. Gestational glucose intolerance, including categories not meeting the gestational diabetes threshold, was associated with increased odds for offspring overweight/obesity at late adolescence.

1048-P: Glucose Intolerance in Pregnancy and Offspring Obesity in Late Adolescence

Objective: Gestational hyperglycemia is associated with deleterious neonatal outcomes, but long-term risks for offspring obesity are less clear. We estimated the odds for offspring adolescent overweight and obesity among mothers with gestational glucose intolerance. Methods: In a mother-offspring, historical cohort, the Israel military conscription dataset was linked to a large health maintenance organization. Included were women who were evaluated at adolescence and performed two-step gestational diabetes screening (mean age, 31 years) with a 50-g glucose challenge test (GCT) , followed by a 100-g oral glucose tolerance test (OGTT) if abnormal. Glucose tolerance categories included gestational normoglycemia, abnormal GCT with normal OGTT, impaired glucose tolerance (IGT; one abnormal OGTT value) , and gestational diabetes. The primary outcome was offspring overweight/obesity (BMI≥85th percentile) at adolescence, measured prior to military conscription. Logistic regression models were applied. Results: Of 33,482 mother-offspring pairs, overweight and obesity were observed in 6,516 offspring. Across increasing categories of pregnancy glycemia, the proportions of offspring with adolescent overweight/obesity increased: normoglycemia, 19%; abnormal GCT with normal OGTT, 22%; gestational IGT, 24%; and gestational diabetes, 25%, P&amp;lt;0·0001. Corresponding odds ratios after adjustment for mother's late-adolescent characteristics (sociodemographic confounders and BMI) and pregnancy age were 1.2 (95%CI, 1.1-1.4) , 1.3 (95%CI, 1.2-1.5) , and 1.4 (95%CI, 1.3-1.6) , respectively. Further adjustment for offspring birth weight percentile and sociodemographic variables did not materially change results. Associations were more pronounced with increasing obesity severity. Conclusions: Gestational glucose intolerance, including categories not meeting the gestational diabetes threshold, were associated with increased odds for offspring overweight/obesity at late adolescence. Disclosure C.D.Bendor: None. Y.Lebenthal: Advisory Panel; Lilly, Novo Nordisk, Research Support; Novo Nordisk, Pfizer Inc., Speaker's Bureau; Pfizer Inc. A.Afek: None. G.Chodick: None. G.Twig: None. A.Bardugo: None. R.Rotem: None. E.Derazne: None. H.C.Gerstein: Advisory Panel; Abbott, Eli Lilly and Company, Hanmi Pharm. Co., Ltd., Novo Nordisk, Pfizer Inc., Sanofi, Viatris Inc., Consultant; Kowa Company, Ltd., Other Relationship; DKSH, Eli Lilly and Company, Sanofi, Zuellig Pharma Holdings Pte. Ltd., Research Support; AstraZeneca, Eli Lilly and Company, Merck &amp; Co., Inc., Novo Nordisk, Sanofi. D.Tzur: None. O.Pinhas-hamiel: Advisory Panel; Novo Nordisk, Speaker's Bureau; Pfizer Inc. A.M.Tsur: None. T.Cukierman-yaffe: Research Support; European Association for the Study of Diabetes, Medtronic, Merck Sharp &amp; Dohme Corp., Novo Nordisk, Speaker's Bureau; AstraZeneca, Eli Lilly and Company, Medtronic, Merck Sharp &amp; Dohme Corp., Novo Nordisk, Sanofi.

Treating Gestational Diabetes Reduces Birth Weight but Does Not Affect Infant Adiposity Across the 1st Year of Life.

The continuum of maternal glycemia in pregnancy shows continuous associations with both 1) neonatal birth weight at delivery and 2) subsequent adiposity later in childhood. While treating gestational diabetes mellitus (GDM) can lower birth weight and thereby disrupt the former association, it is unclear if such treatment reduces childhood adiposity. Thus, we sought to compare anthropometry across the 1st year of life between infants born to women who were treated for GDM and those with lesser degrees of gestational dysglycemia (untreated). Anthropometric measurements were performed at 3 months and 12 months of life in 567 infants born to women comprising the following four gestational glucose tolerance groups: 1) women with normoglycemia on both glucose challenge test (GCT) and oral glucose tolerance test (OGTT) in pregnancy; 2) women with an abnormal GCT but normal OGTT; 3) those with mild gestational impaired glucose tolerance; and 4) women treated for GDM. Birth weight progressively increased across the three untreated groups but was lowest in women treated for GDM (P = 0.0004). Similarly, women treated for GDM had the lowest rate of macrosomia (P = 0.02). Conversely, however, there were no differences among the four groups in weight z score, length z score, weight-for-length z score, or BMI z score at either 3 months or 12 months (all P values = NS). Similarly, there were no differences among the groups in triceps/biceps/subscapular/suprailiac skinfold thickness or sum of skinfolds at either 3 months or 12 months (all P values = NS). Despite reducing birth weight and macrosomia, the treatment of GDM does not have analogous effects on infant adiposity across the 1st year of life.

Accuracy of capillary blood glucose for 50-g glucose challenge test for gestational diabetes screening.

To assess the accuracy of capillary blood glucose (CBG) compared to conventional venous plasma glucose (VPG) testing for 50-g glucose challenge test (GCT) in gestational diabetes (GDM) screening. A total of 300 women were enrolled and 50-g GCT for GDM screening was offered. At 1h after glucose loading, CBG was evaluated by CONTOUR® PLUS glucose meter by well-trained nurses immediately after venipuncture for VPG. Results of CBG were compared with those from VPG to evaluate its accuracy. Women with venous plasma glucose > 140mg/dL were offered 100-g OGTT for GDM diagnosis. The mean age was 30.2years and the mean gestational age at testing was 21.8weeks. GDM was diagnosed in 34 women (11.3%). The mean VPG was 142.1 ± 32.9mg/dL and the mean CBG was 129.3 ± 33.5mg/dL. Mean difference was -12.3 ± 12.5mg/dL, corresponding to -8.8 ± 11.4%. CBG significantly correlated with VPG with correlation coefficient of 0.929, p < 0.001. In the detection of abnormal 50-g GCT results (VPG ≥ 140mg/dL), at 126mg/dL cutoff, CBG had sensitivity of 92.5%, specificity of 81.8%, and positive and negative predictive values of 82.8%and 92%. None of the GDM would have been missed if CBG was used. CBG by a certified glucose meter could be considered as an alternative to conventional VPG testing for 50-g GCT for GDM screening using 126mg/dL cutoff value.

Is an isolated abnormal 1-hour glucose challenge test associated with adverse pregnancy outcomes?

Is an isolated abnormal 1-hour glucose challenge test associated with adverse pregnancy outcomes?

High Levels of 25-OH-Vitamin D and Copper in Pregnant Women with Abnormal Glucose Challenge Test.

Several hormones and elements are involved in the homeostasis of glucose metabolism during pregnancy. This present study determined the differences among the factors involved in glucose regulation for pregnant women with and without an abnormal glucose challenge test (GCT), but without gestational diabetes mellitus, during the second trimester of gestation and the postpartum period. One hundred and six pregnant women who had received routine prenatal and postpartum examinations at our hospital were recruited. Sugar-related tests and the levels of pregnancy-associated hormones and 25-OH-vitamin D were performed using a clinical autoanalyzer; six elements were assessed using graphite furnace atomic absorption spectrometry or inductively coupled plasma mass spectrometry. The women in the abnormal GCT group (n = 27) featured significantly higher levels of 25-OH-vitamin D (p = 0.006) and copper (p < 0.001) than those in the normal GCT group (n = 79). After adjusting for possible pregnancy factors, abnormal GCT remained the significant contributing factor for the elevated levels of 25-OH-vitamin D and copper during gestation (p = 0.046 and 0.002, respectively). Furthermore, significant positive correlations existed between 25-OH-vitamin D and glucose after a 50-g GCT (p = 0.001), 25-OH-vitamin D and HbA1C (p = 0.004), serum copper and glucose after a 50-g GCT (p = 0.003), and serum copper and HbA1C (p < 0.001). We conclude that blood 25-OH-vitamin D and copper are strongly correlated with glucose levels during gestation; these two factors are potential clinical predictors for maternal impaired glucose tolerance and, indirectly, for reducing perinatal risks and neonatal complications.

Evaluation of Perinatal Outcome in Women with Impaired Glucose Homeostasis During Pregnancy

Background: Glucose tolerance testing in pregnancy identifies many women with glycaemic responses that exceed normal range but that do not meet the threshold required to diagnose Gestational Diabetes Mellitus. It is controversial whether maternal hyperglycemia less severe than in diabetes is associated with increased risk of adverse pregnancy outcome or not. Materials and methods: All women were subjected to Glucose Challenge Test(GCT) with 50 gram glucose either at first visit or between 24-28 weeks on the basis of risk profile. High risk cases were screened at first visit and the rest between 24-28 weeks. Patients with a GCT value ≥200mg/dl were not subjected for GTT and were diagnosed as GDM.Value of GCT &lt;140 mg/dl was taken as normal. Irrespective of GCT result, women were subjected to Oral Glucose Tolerance Test (OGTT) as recommended by WHO with 75 gram glucose using WHO criteria. Study group was identified with 4 categories with abnormal glucose homoeostasis as defined by the following criteria: 1. Abnormal GCT (&gt;140 mg/dl) with normal OGTT; 2. Normal GCT with only Impaired Fasting Glucose(IFG) in OGTT; 3. Normal GCT with Gestational Glucose Intolerance(GGI); 4. Patients diagnosed as GDM: a. If fasting is &gt;126mg/dl; b. If 2hr OGTT ≥ 140mg/dl &amp; ≤ 199 mg/dl; c. If value of either GCT or OGTT &gt;200 mg/dl. The control group comprised of women with normal GCT and normal OGTT. In all the above groups, adverse prenatal outcome and maternal outcomes were evaluated by the primary and secondary outcome measures. Results: There were 10 cases (15.3%) of hypertensive disorder of pregnancy in the study group (3 cases of gestational hypertension in abnormal GCT, 3 cases of pre eclampsia in each GGI and GDM and 1 antepartum eclampsia in GGI category) and 2 cases in control group (3%) (p=0.03). There were 2 cases of Fetal Growth Reduction (FGR) and 5 cases of Premature Rupture Of Membranes(PROM) in both study and control group. There was 1 case of cholestasis of pregnancy in study group. Term inductions were 11 and 13 in the study and control group respectively.Within the study group number of cases induced were more in GGI(n=7) and GDM(n=4) category. There were 14 caesarean sections (21.5%) and 2 (3%) instrumental deliveries among the study group. However there were 6 caesarean sections (9.2%) and no instrumental deliveries among control groups. The rate of elective LSCS is more in GDM (n=5) vs other 3 categories and the difference is significant (p=0.04) The overall number of LSCS (14 cases) was significantly higher in GDM. Conclusion: Cases with abnormal glucose homeostasis of lesser degree than GDM, like only abnormal GCT, IFG and GGI also were observed to have adverse maternal outcomes than controls, in form of hypertensive disorders of pregnancy, significantly higher LSCS rates, and increased risk of macrosomia. Instead of 2 step procedure, single step screening cum diagnostic test with 75 gm OGTT for diagnosing GDM could be an option to be universally practiced.

Abnormal glucose challenge test in absence of oral glucose tolerance test – are there consequences?

This is a retrospective analysis of mothers with abnormal 1-hour, 50-grams glucose challenge test (GCT) who did not take a 3-hour, 100-gram oral glucose tolerance test (OGTT). This study group of women was compared to three control groups, based on an OGTT diagnostic test- normal OGTT, single pathological value and gestational diabetes mellitus. Overall- 4,185 women were included and sub-divided accordingly into four groups: Group A-340 (8.12%)- no OGTT; Group B-2,585 (61.77%)- Norm OGTT (All values normal); Group C- 564 (13.48%)- SinOGTT (single pathological value) and Group D- 696 (16.63%)- Gestational Diabetes Mellitus (GDM, ≥ 2 pathological values). Groups A, C and D had higher rates of intrapartum Caesarean Delivery (10.29%, 11.52% and 10.19% vs. 8.43%, p < .0001). Group A had highest rates of neonatal adverse outcomes, as neonatal intensive care unit (NICU) admission (12.4% vs. 8.4%, 11.0% and 10.0%, p = .039), small for gestational age (SGA) neonates (7.0% vs. 5.3%, 3.7% and 6.0%, p = .0092) and neonatal hypoglycaemia (3.5% vs. 1.3%, 3.2% and 2.9%, p = .007). A multivariable regression revealed that having an abnormal GCT without an OGTT was an independent risk factor for neonatal intensive care unit admission, neonatal hypoglycaemia and intrapartum caesarean delivery. We concluded that women with pathological GCT who did not complete OGTT have higher rates of obstetric adverse outcomes. They should be closely monitored during delivery and should not be overlooked. IMPACT STATEMENT What is already known on this subject? Adverse outcomes of gestational diabetes mellitus are well established. But, the group of women who fail to complete a confirmatory OGTT following a pathological GCT is not well described. What the results of this study add? Our results point out that women who fail to complete an OGTT, suffer from higher rates of obstetric complications, presumably attributed to disrupted glucose values, but also to poor prenatal care. What the implications are of these findings for clinical practice and/or further research? These women should not be overlooked. They should be closely monitored during labour and delivery.

943 Abnormal glucose screening in an index pregnancy and gestational diabetes in a subsequent pregnancy

In a non-diabetic pregnancy, the current practice is universal screening for gestational diabetes (GDM) using a 1-hour glucose challenge test (GCT) regardless of prior history. We aimed to determine whether an abnormal 1-hour GCT from an index pregnancy (PG1) can be used to guide GDM testing in a subsequent pregnancy (PG2). This was a retrospective cohort study of women who delivered 2 singleton pregnancies at >24 weeks from June 2009-December 2018 at a single institution. All patients had an abnormal PG1 GCT result (> 140 mg/dL). GDM was defined by GCT of >200mg/dL, >2 elevated values on a 3-hour diagnostic test (Carpenter-Coustan criteria), or a diagnosis by ICD codes. Univariable and multivariable analyses (MVA) were performed to examine the relationship between GDM in PG2 with variables from PG1. Given the high likelihood of GDM in subsequent pregnancies among women with GDM in PG1, the MVA was restricted to patients who were non-diabetic in PG1. 820 women met inclusion criteria, 356 (43.4%) had an abnormal 1-hour GCT in PG2, 233 (28.4%) developed GDM in PG2, and 48 (20.6%) of patients received a diagnosis of GDM without meeting laboratory criteria (Table 1). In MVA of subjects in a non-diabetic PG1, those with GDM in PG2 were significantly more likely to have higher GCTs in PG1, be of Asian race and have had gestational hypertension (gHTN) in PG1 (Table 2). In a non-diabetic PG1, the risk of GDM in PG2 increases with PG1 GCT result, Asian race and a history of gHTN. Of all patients with an abnormal PG1 GCT, regardless of PG1 diabetic status, 43.4% had an abnormal 1-hour GCT in PG2 with over a quarter of these patients diagnosed with GDM. Furthermore, our observation that 20.6% of patients diagnosed with GDM without laboratory criteria suggests that these women are considered at higher risk and are receiving the diagnosis of GDM regardless of diagnostic criteria. Thus, consideration can be given to supplant universal screening using a 1-hour GCT with direct diagnostic testing in women with a history of abnormal 1-hour screens in a prior pregnancy.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

242: History of abnormal glucose challenge test as a predictor of abnormal results in subsequent pregnancy

242: History of abnormal glucose challenge test as a predictor of abnormal results in subsequent pregnancy

Association of glucose levels in pregnancy with use of health care services

AimsTo determine whether women with abnormal gestational diabetes (GDM) screening test results short of frank GDM have increased health-services utilization compared to women with normal results. MethodsWe conducted a retrospective-cohort study among 29,999 women enrolled in Kaiser Permanente Northwest who completed GDM screening (two-step method: 1-h, 50-g glucose-challenge test (GCT); 3-h, 100-g oral-glucose-tolerance test (OGTT)). Test results were categorized as normal GCT (referent, n = 25,535), normal OGTT (n = 2246), abnormal OGTT but not GDM (n = 1477), and GDM (n = 741). Rate ratios (RRs) were calculated for utilization measures and analyses were age- and BMI-adjusted. ResultsCompared to women with normal GCT, rates for obstetrical ultrasound, noninvasive and invasive antenatal testing, and ambulatory visits to the obstetrics department were significantly greater among women with abnormal OGTT (RRs 1.2 [95%CI 1.1, 1.4], 1.3 [1.1, 1.4], 1.7 [1.3, 2.3], and 1.1 [1.1, 1.1], respectively) and GDM (RRs 1.8, 1.8, 2.0, and 1.3, respectively). Women with abnormal OGTT results were more likely to visit a dietician than women with normal GCT; RRs ranged from 4.0 [3.3, 4.9] for women with abnormal GCT but normal OGTT to 72.1 [64, 81] for women with GDM. ConclusionsHealth-services utilization increased with severity of glucose result, even among women without GDM.

Does Serum Hemoglobin A1C during Early Pregnancy Predict Performance on the 1-Hour Glucose Challenge Test? [28B

INTRODUCTION: Our objective was to determine the negative and positive predictive values of hemoglobin A1c (HgbA1c) levels, conceptualized as a screening test, in predicting abnormal 1-hour glucose challenge test (GCT) results in pregnancy. METHODS: This was a retrospective cohort study. We calculated the negative predictive value of HgbA1c levels in predicting normal 1-hour GCT (less than or equal to 140 mg/dl) and the positive predictive value in predicting an abnormal 1-hour GCT of greater than 140 mg/dl. RESULTS: We examined 635 pregnancies where the HgbA1c was measured in the same patient on the same day as or before the 1-hour GCT was performed. The median time interval between performance of the HgbA1c test and the 1-hour GCT was 95 days (IQR 56-122 days). Among women with HgbA1c levels less than or equal to 4.9, 5.0, and 5.1, the probability of their 1-hour GCT being 140 mg/dl or less was 91.3%, 91.0% and 90.1%, respectively. Among our study population, 14.5%, 22.8%, and 35.0% had HgbA1c levels less than or equal to 4.9, 5.0 and 5.1, respectively. Among women with HgbA1c levels greater than 6.1, the probability of their 1-hour GCT being greater than 140 mg/dl was 100%. However, only 0.3% of our population had HgbA1c greater than 6.1. CONCLUSION: Our study adds to the body of evidence that HgbA1c cannot replace the 1-hour GCT as a screening test for gestational diabetes, but low values can reliably predict a normal 1-hour GCT. Therefore, some women could be spared from doing the 1-hour GCT.

Glucose screening in pregnancy and future risk of cardiovascular disease in women: a retrospective, population-based cohort study

In studies to date, gestational diabetes has consistently been associated with an increased future risk of cardiovascular disease, irrespective of the antepartum screening protocol or diagnostic criteria by which gestational diabetes is diagnosed. We reasoned that the resultant heterogeneity in the severity of dysglycaemia in women with gestational diabetes suggests that the relationship between gestational glycaemia and subsequent cardiovascular disease probably extends into the non-diagnostic range. Thus, we hypothesised that glucose screening in pregnancy would identify future risk of cardiovascular disease in women who did not have gestational diabetes. We did a population-based cohort study using information from health-care administrative databases from the Ministry of Health and Long Term Care of Ontario (Canada). We identified all women in Ontario who had a 50 g oral glucose challenge test in pregnancy between 24 and 28 weeks gestation with a livebirth delivery between July 1, 2007, and Dec 31, 2015. Women who had a history of diabetes before pregnancy or had been previously hospitalised for cardiovascular disease were excluded. Women with a 1-h post-challenge plasma glucose concentration of 11·1 mmol/L or greater were considered to have gestational diabetes, as were women with a reading between 7·8 and 11·0 mmol/L inclusive for whom diabetes was recorded as a diagnosis on the delivery hospital record. The study population was divided into six groups based on the results of the glucose challenge test (≤4·8 mmol/L; 4·9-5·5 mmol/L; 5·6-6·2 mmol/L; 6·3-6·9 mmol/L; 7·0-7·9 mmol/L; and ≥8·0 mmol/L). The primary outcome was cardiovascular disease (a composite of hospitalisation for myocardial infarction, acute coronary syndrome, stroke, coronary artery bypass grafting, percutaneous coronary intervention, or carotid endarterectomy). All women were followed up from the index pregnancy until cardiovascular disease event, death, migration, or Sept 30, 2017, whichever came first. 259 164 women were identified as eligible for this study: 13 609 who had gestational diabetes, and 245 555 women without gestational diabetes. The women were followed up over a median 3·9 years (IQR 2·8-5·6) for the development of cardiovascular disease. Each 1 mmol/L increment in the glucose challenge test result was associated with a 13% higher risk of cardiovascular disease (after adjustment for age, ethnicity, income, and rurality, adjusted hazard ratio [HR] 1·13, 95% CI 1·04-1·22). This relationship persisted after excluding women with gestational diabetes (1·14, 1·01-1·28). In women without gestational diabetes, those with an abnormal glucose challenge test result (≥7·8 mmol/L) and those with a result between 7·2 and 7·7 mmol/L had an increased risk of cardiovascular disease (HR 1·94, 95% CI 1·29-2·92; and 1·65, 0·99-2·76, respectively), compared with those with a result of 7·1 mmol/L or less (overall p=0·003). The relationship between gestational glycaemia and subsequent risk of cardiovascular disease extends into the normoglycaemic range. Accordingly, glucose screening in pregnancy could identify future risk of cardiovascular disease in women who do not have gestational diabetes. None.

414: High-normal 50-gram glucose challenge test and future metabolic diseases: a population- based study

A 1-hour 50-gram glucose challenge test (GCT) is the first step in the screening for gestational diabetes mellitus (GDM). Accumulating evidence show that women with high- normal GCT levels are at elevated risk for immediate obstetric complications such as large for gestational age newborns and greater likelihood for caesarean delivery. We sought to examine the risk for metabolic disorders later in life, among women with high-normal GCT levels, as compared to low normal and abnormal GCT. This cohort study included all pregnant women who underwent GCT between the years 2005 to 2018 at the Central District of Clalit Health Services, the largest health maintenance organization in Israel. Rates of metabolic diseases (MTD) were compared between the three study groups: women with history of only Low-normal GCT (<124 mg/dL), High normal (125- 139 mg/dL) and abnormal GCT >140 mg/dL. Data on maternal ages and GCT results for each test performed, as well as MTD such as diabetes and obesity were collected and analyzed from the computerized database. Multivariable survival model was used to study the association between GCT levels and MTD risk, while adjusting for maternal age. A total of 66,869 women performed 1 to 10 GCTs to a total of 117,435 tests during the study period; 23% of study participants (n=15,360) had at least one abnormal result; 11.3% (n=7566) of participants had a diagnosis of MTD. As compared to women with low normal GCT (only), women with a history of high normal and abnormal GCT were at higher risk for MTD (10.4% vs. 12.4% and 13.0%, p<0.001, age adjusted HR=1.18; 95%CI 1.09-1.24, and 1.18; 95%CI 1.11-1.25, for high normal and abnormal GCT, respectively). There was no significant difference in MTD risk between women with history of high normal and abnormal GCT results (age adjusted HR=1.02; 95%CI 0.94-1.10; p=0.67). As compared to women with low normal GCT, women with high normal GCT, similarly to women with abnormal GCT, are at increased MTD risk. Although GCT is a screening test, it may be a predictor of MTD later in life, and women with high normal GCT results may benefit from close monitoring of their metabolic status.

Pregnant women may be sweeter in the summer: Seasonal changes in glucose challenge tests results. A population-based study

AimsA 1-hour, 50-gram glucose challenge test (GCT) is the first step in the diagnosis of gestational diabetes mellitus (GDM). Seasonal fluctuations in fasting glucose levels and GCT results were previously described. We sought to investigate seasonal changes in GCT results in a large cohort. MethodsGCT results were analyzed of all women insured at the Central District of Clalit Health Services (the largest health maintenance organization in Israel), between the years 2005 and 2016. ResultsA total of 101,359 GCT results were analyzed. Mean GCT was 110 ± 28.9 mg/dL, and 14.5% (n = 14,652) were pathological. Both the mean and the incidence of pathological GCT were lowest in the winter, followed by spring, fall, and summer, (p for trend < 0.001). The difference in mean GCT between winter and summer was 7.82 ± 0.24 mg/dL (95% CI, 7.35–8.29). After adjustment for BMI and age, having a GCT in the winter was independently associated with the lowest risk for pathological GCT, as compared to all other seasons. ConclusionsSeasonal changes in GCT results should be studied further in additional regions, and if found, the cutoff threshold for abnormal GCT should be re-examined and adapted to local weather conditions and seasonal variability.