False-Positive 1-Hour Glucose Challenge Test and Adverse Perinatal Outcomes

Gestational Glucose Intolerance and Birth Weight-Related Complications

OBJECTIVE

To evaluate the risks of large-for-gestational-age birth weight (LGA) and birth weight-related complications in pregnant individuals with gestational glucose intolerance, an abnormal screening glucose loading test result without meeting gestational diabetes mellitus (GDM) criteria.

METHODS

In a retrospective cohort study of 46,989 individuals with singleton pregnancies who delivered after 28 weeks of gestation, those with glucose loading test results less than 140 mg/dL were classified as having normal glucose tolerance. Those with glucose loading test results of 140 mg/dL or higher and fewer than two abnormal values on a 3-hour 100-g oral glucose tolerance test (OGTT) were classified as having gestational glucose intolerance. Those with two or more abnormal OGTT values were classified as having GDM. We hypothesized that gestational glucose intolerance would be associated with higher odds of LGA (birth weight greater than the 90th percentile for gestational age and sex). We used generalized estimating equations to examine the odds of LGA in pregnant individuals with gestational glucose intolerance compared with those with normal glucose tolerance, after adjustment for age, body mass index, parity, health insurance, race and ethnicity, and marital status. In addition, we investigated differences in birth weight-related adverse pregnancy outcomes.

RESULTS

Large for gestational age was present in 7.8% of 39,685 pregnant individuals with normal glucose tolerance, 9.5% of 4,155 pregnant individuals with gestational glucose intolerance and normal OGTT, 14.5% of 1,438 pregnant individuals with gestational glucose intolerance and one abnormal OGTT value, and 16.0% of 1,711 pregnant individuals with GDM. The adjusted odds of LGA were higher in pregnant individuals with gestational glucose intolerance than in those with normal glucose tolerance overall (adjusted odds ratio [aOR] 1.35, 95% CI 1.23-1.49, P <.001). When compared separately with pregnant individuals with normal glucose tolerance, those with either gestational glucose intolerance subtype had higher adjusted LGA odds (gestational glucose intolerance with normal OGTT aOR 1.21, 95% CI 1.08-1.35, P <.001; gestational glucose intolerance with one abnormal OGTT value aOR 1.77, 95% CI 1.52-2.08, P <.001). The odds of birth weight-related adverse outcomes (including cesarean delivery, severe perineal lacerations, and shoulder dystocia or clavicular fracture) were higher in pregnant individuals with gestational glucose intolerance with one abnormal OGTT value than in those with normal glucose tolerance.

CONCLUSION

Gestational glucose intolerance in pregnancy is associated with birth weight-related adverse pregnancy outcomes. Glucose lowering should be investigated as a strategy for lowering the risk of these outcomes in this group.

Physiological subtypes of gestational glucose intolerance and risk of adverse pregnancy outcomes

BACKGROUND

Women with gestational glucose intolerance, defined as an abnormal initial gestational diabetes mellitus screening test, are at risk of adverse pregnancy outcomes even if they do not have gestational diabetes mellitus. Previously, we defined the physiological subtypes of gestational diabetes mellitus based on the primary underlying physiology leading to hyperglycemia and found that women with different subtypes had differential risks of adverse outcomes. Physiological subclassification has not yet been applied to women with gestational glucose intolerance.

OBJECTIVE

We defined the physiological subtypes of gestational glucose intolerance based on the presence of insulin resistance, insulin deficiency, or mixed pathophysiology and aimed to determine whether these subtypes are at differential risks of adverse outcomes. We hypothesized that women with the insulin-resistant subtype of gestational glucose intolerance would have the greatest risk of adverse pregnancy outcomes.

STUDY DESIGN

In a hospital-based cohort study, we studied women with gestational glucose intolerance (glucose loading test 1-hour glucose, ≥140 mg/dL; n=236) and normal glucose tolerance (glucose loading test 1-hour glucose, <140 mg/dL; n=1472). We applied homeostasis model assessment to fasting glucose and insulin levels at 16 to 20 weeks' gestation to assess insulin resistance and deficiency and used these measures to classify women with gestational glucose intolerance into subtypes. We compared odds of adverse outcomes (large for gestational age birthweight, neonatal intensive care unit admission, pregnancy-related hypertension, and cesarean delivery) in each subtype to odds in women with normal glucose tolerance using logistic regression with adjustment for age, race and ethnicity, marital status, and body mass index.

RESULTS

Of women with gestational glucose intolerance (12% with gestational diabetes mellitus), 115 (49%) had the insulin-resistant subtype, 70 (27%) had the insulin-deficient subtype, 40 (17%) had the mixed pathophysiology subtype, and 11 (5%) were uncategorized. We found increased odds of large for gestational age birthweight (primary outcome) in women with the insulin-resistant subtype compared with women with normal glucose tolerance (odds ratio, 2.35; 95% confidence interval, 1.43-3.88; P=.001; adjusted odds ratio, 1.74; 95% confidence interval, 1.02-3.48; P=.04). The odds of large for gestational age birthweight in women with the insulin-deficient subtype were increased only after adjustment for covariates (odds ratio, 1.69; 95% confidence interval, 0.84-3.38; P=.14; adjusted odds ratio, 2.05; 95% confidence interval, 1.01-4.19; P=.048). Among secondary outcomes, there was a trend toward increased odds of neonatal intensive care unit admission in the insulin-resistant subtype in an unadjusted model (odds ratio, 2.09; 95% confidence interval, 0.99-4.40; P=.05); this finding was driven by an increased risk of neonatal intensive care unit admission in women with the insulin-resistant subtype and a body mass index of <25 kg/m². Infants of women with other subtypes did not have increased odds of neonatal intensive care unit admission. The odds of pregnancy-related hypertension in women with the insulin-resistant subtype were increased (odds ratio, 2.09; 95% confidence interval, 1.31-3.33; P=.002; adjusted odds ratio, 1.77; 95% confidence interval, 1.07-2.92; P=.03) compared with women with normal glucose tolerance; other subtypes did not have increased odds of pregnancy-related hypertension. There was no difference in cesarean delivery rates in nulliparous women across subtypes.

CONCLUSION

Insulin-resistant gestational glucose intolerance is a high-risk subtype for adverse pregnancy outcomes. Delineating physiological subtypes may provide opportunities for a more personalized approach to gestational glucose intolerance.

Screening for gestational diabetes mellitus and hyperglycemia in pregnancy with the glucose challenge test administered in early pregnancy

OBJECTIVE

To determine the cut-off value for the 75-g glucose challenge test administered in early pregnancy to screen for gestational diabetes mellitus and abnormal carbohydrate metabolism in pregnancy.

METHODS

A prospective study involving 1500 antenatal patients attending a community hospital. Patients were screened with the 75-g 1-h glucose challenge test in early pregnancy and subsequently tested with the 75-g 2-h glucose tolerance test to diagnose gestational diabetes mellitus. Statistical methods were employed to determine the optimal plasma glucose cut-off value for a positive result in early pregnancy.

RESULTS

A glucose challenge test value of 6.0 mmol/L (108 mg/dl) or more was selected as the preferred cut-off level for further testing with a sensitivity of 83.5% (95% confidence interval [CI] 77.0%-88.9%) and specificity of 49.2% (95% CI 46.5%-52.0%).

CONCLUSION

An early pregnancy glucose challenge test reading of 6.0 mmol/L (108 mg/dl) or more is effective in screening for gestational diabetes mellitus; a value of 10.0 mmol/L (180 mg/dl) or more is effective for finding pre-pregnancy abnormalities of carbohydrate metabolism. The false-positive glucose challenge test diagnoses gestational hyperglycemia, the treatment of which will improve perinatal outcome. Further testing based on risk factors will exclude a false-negative glucose challenge test. A combination of universal early pregnancy screening and selective risk-factor testing is recommended to detect the full range of abnormalities of carbohydrate metabolism encountered in pregnancy.

Elevated Glucose Challenge Test in a Nondiabetic Index Pregnancy and Gestational Diabetes in a Subsequent Pregnancy

OBJECTIVE

The aim of this study was to evaluate whether a 1-hour glucose challenge test (GCT) ≥140 mg/dL in a nondiabetic index pregnancy is associated with the development of gestational diabetes mellitus (GDM) in a subsequent pregnancy.

STUDY DESIGN

We performed a retrospective cohort study from a single institution from June 2009 to December 2018. Women with a nondiabetic index singleton gestation who underwent a 1-hour GCT at 24 to 28 weeks and had a successive singleton delivery were included. GDM was defined by a 1-hour GCT of ≥ 200 mg/dL, ≥2 of 4 elevated values on a 3-hour GCT, or a diagnosis of GDM defined by International Classification of Disease codes in the electronic medical record. Univariable analyses were performed to evaluate the associations between an elevated 1-hour GCT result in the index pregnancy, maternal characteristics, and the development of GDM in the subsequent pregnancy. Variables found to be significant (p < 0.05) were included in multivariable analysis.

RESULTS

A total of 2,423 women were included. Of these, 340 (14.0%) had an elevated 1-hour GCT in the index pregnancy. Women with an elevated 1-hour GCT in the index pregnancy compared with those without were significantly more likely to be older, married, privately insured, of Hispanic ethnicity or Asian race, chronically hypertensive, have a higher body mass index (BMI), have a shorter inter-pregnancy interval, and to develop GDM in the subsequent pregnancy (14.4 vs. 3.3%, p < 0.001). In multivariable analysis, an elevated 1-hour GCT (adjusted odds ratio [aOR]: 4.54, 95% confidence interval [CI]: 3.02-6.81), first-trimester BMI ≥30 kg/m² in the index pregnancy (aOR: 3.10, 95% CI: 2.03-4.71), Asian race (aOR: 2.96, 95% CI: 1.70-5.12), Hispanic ethnicity (aOR: 2.11, 95% CI: 1.12-4.00), and increasing age (aOR: 1.07, 95% CI: 1.02-1.12) were significantly associated with an increased risk of GDM in the subsequent pregnancy.

CONCLUSION

An elevated 1-hour GCT in a nondiabetic index pregnancy is associated with a fourfold increased risk of GDM in a subsequent pregnancy.

KEY POINTS

· An abnormal 1 hour GCT in an index pregnancy is associated with GDM in a subsequent pregnancy.. · An abnormal 1 hour GCT may be an independent risk factor for GDM in a subsequent pregnancy.. · An abnormal 1 hour GCT is associated with a 4 fold increased risk of GDM in a subsequent pregnancy..

Do patients with a single abnormal OGTT value need a globally admitted definition such as "borderline GDM"? Pregnancy outcomes of these women and the evaluation of new inflammatory markers

INTRODUCTION

One of the approaches to diagnose Gestational Diabetes Mellitus (GDM) is to detect two or more elevated values in 3-h Glucose Tolerance Test (OGTT) after an abnormal 50 gr Glucose Challenge Test (GCT). Patients with single elevated OGTT generally postulated as healthy; however, these patients could experience adverse perinatal and maternal issues more frequently. We aimed to investigate the maternal and neonatal outcomes of women with single abnormal OGTT primarily by comparing these women with healthy controls and GDM patients. Secondarily; Mean Platelet Volume (MPV), Platelet Distribution Width (PDW), Neutrophil to Lymphocyte Ratio (NLR) and Platelet to Lymphocyte Ratio (PLR) which were defined as novel inflammatory markers recently, were evaluated among these women within the first trimester and before delivery values whether these markers could use as a predictive marker of GDM.

MATERIALS AND METHODS

A retrospective cohort study was achieved in Bursa Yuksek Ihtisas Education and Training Hospital between January 2016 and April 2020. Patients who had GCT and OGTT at 24th-28th weeks of gestation were reviewed. Patients with GDM, women with single elevated OGTT value, and women with normal OCT values were recruited at the study as groups 1, 2, and 3 respectively. Maternal-neonatal outcomes and postpartum complications were reviewed from hospital registry system. Each complication were accumulated in a group entitled peripartum complication (a patient who had more than 1 complication for example preeclampsia and acute fetal distress was added in the peripartum complication group as one patient).The novel inflammatory markers were evaluated as NLR and PLR, and thrombocyte parameters as MPV and PDW were compared within the groups, and between the groups individually in the time period of first trimester and before delivery.

RESULTS

A total of 10,579 patients were screened with OCT, of these a total of 1718 patients' results were between 140 mg/dl and 199 mg/dl. The numbers of the women who diagnosed GDM and who had single elevated OGTT were 508 and 469 respectively. Numbers of the patients who gave birth in our hospital and whose data were reviewed adequately were 464 in groups 1, 406 in group 2, and 768 in group 3.Patients with single elevated OGTT had increased rates of peripartum complication, acute fetal distress (AFD), IUGR, preterm delivery, cesarean delivery rate, macrosomia, labor arrest, blood component transfusion, post-partum complication and stillbirth than healthy controls. Statistical analysis of comparison between group 2 and 3 has revealed that; patients with single elevated OGTT had more peripartum complication (p = .032; odds ratio [OR] = 1.2, 95% CI: 1.02-1.54), had more babies with macrosomia (p < .001; [OR] = 1.7, 95% CI: 1.2-2.4), had more postpartum complication (p = .040; [OR] = 3, 95% CI: 0.997-9.1), and had higher cesarean rates (p < .001; [OR] = 1.29, 95% CI: 1.1-1.4).Evaluating the first trimester CBC parameters between groups; only PLR differed statistically significant in GDM patients. These parameters before delivery were also analyzed PLR and NLR values did not differ between all groups, on the other hand; MPV values were higher and PDW values were lower in healthy controls comparing GDM and single elevated OGTT group.

CONCLUSION

Patients with single elevated OGTT had a higher risk of maternal and neonatal consequences than women with normal OCT, which was comparable levels to patients with GDM. These patients should not be underestimated and could be classified as an individual diagnose such as "Borderline GDM." To intervene in these patients with dietary advice and lifestyle changes like exercise could decrease neonatal and maternal adverse outcomes.

Hyperinsulinemia during pregnancy across varying degrees of glucose tolerance: An examination of the Kraft database

AIM

Hyperinsulinemia is a known underlying driver of metabolic disease; however, its role in pregnancy complications is less understood due to insulin measurement not being a part of standard clinical assessments. This study aimed to characterize hyperinsulinemia in pregnancy by gestational diabetes (GD) status using Kraft methodology.

METHODS

We analyzed historical data from 926 pregnant women who underwent a 100-g oral glucose tolerance test (OGTT), which included insulin measurement. Subjects were grouped by GD diagnosis status ("Normal", "Borderline", "GD") and insulin responses over 3 h were compared between groups.

RESULTS

"GD" was diagnosed in 20.3% of the subjects and 13.8% were grouped as "Borderline." The prevalence of hyperinsulinemia using the Kraft algorithm was 33.1% for Kraft IIB and 42.0% for Kraft III. Compared to normal glucose-tolerant mothers, individuals from the "Borderline" group had an exacerbated insulin response, although not to the same magnitude as those with "GD."

CONCLUSIONS

Dynamic OGTT insulin measurement during pregnancy may provide a meaningful assessment of metabolic risk among women who would otherwise not be diagnosed with GD.

Role of maternal glucose metabolism in the association between maternal BMI and neonatal size and adiposity

BACKGROUND/OBJECTIVE

One potential mechanism by which maternal obesity impacts fetal growth is through hyperglycemia below the threshold for gestational diabetes. Data regarding which measures of maternal glucose metabolism mediate this association is sparse. The objectives of this study were to (i) quantify the associations of maternal pre-pregnancy body mass index (BMI) with neonatal size and adiposity and (ii) examine the role of markers of maternal glucose metabolism as mediators in these associations.

SUBJECTS/METHODS

This is a secondary analysis of 6,379 mother-infant dyads from the Hyperglycemia and Adverse Pregnancy Outcome cohort. Markers of glucose metabolism, including plasma glucose and c-peptide values, Stumvoll first-phase estimate, modified Matsuda index, and oral disposition index were measured and calculated from an oral glucose tolerance test (OGTT) between 24- and 32-weeks' gestation. We calculated the direct effect of maternal BMI category, measured at the time of the OGTT and regressed to estimate pre-pregnancy BMI, on neonatal (1) birth weight (BW), (2) fat mass (FM), (3) % body fat (BF%), and (4) sum of skinfold thickness (sSFT). We then calculated the indirect effect of BMI category on these measures through markers of glucose metabolism.

RESULTS

Maternal BMI category was positively associated with neonatal BW, FM, BF%, and sSFT. Additionally, mothers who were overweight or obese had higher odds of delivering an infant with BW, FM, BF%, or sSFT >90th percentile. Fasting glucose and c-peptide values were the strongest mediators in the linear associations between maternal BMI category and neonatal size and adiposity.

CONCLUSIONS

Maternal overweight and obesity were associated with higher odds of neonatal BW and adiposity >90th percentile. Fasting measures of glucose metabolism were the strongest mediators of these associations, suggesting that future studies should investigate whether incorporation of these markers in pregnant women with obesity may improve prediction of neonatal size and adiposity.

Incidence of large for gestational age and predictive values of third-trimester ultrasound among pregnant women with false-positive glucose challenge test

This cohort study aimed to determine the association between false-positive 50-g GCT and incidence of LGA and to evaluate predictive roles of third-trimester ultrasonographic examination. A total of 200 women with false-positive 50-g GCT and 188 women without GDM risks were enrolled. Third-trimester ultrasonographic examinations were offered. Rate of LGA during third trimester and at birth were compared between groups. Factors associated with LGA and diagnostic properties of third-trimester ultrasonography were evaluated. Incidence of LGA by third-trimester ultrasound and at birth were significantly higher in women with false-positive GCT (19.0% vs. 10.6%, p = .03 and 22% vs. 13.8%; p = .04). Factors associated with LGA included multiparity (adjusted OR 2.32, p = .01), excessive weight gain (adjusted OR 2.57, p = .01) and LGA by ultrasound (adjusted OR 9.79, p < .001). Third-trimester ultrasonography had 47.1% sensitivity, 92.1% specificity and LR + and LR- of 5.96 and 0.57 in identifying LGA infants.Impact statementWhat is already known on this subject? Women with abnormal GCT but normal OGTT (false positive GCT) might have some degree of glucose intolerance so that GDM-related outcomes could develop, including LGA, macrosomia, shoulder dystocia, and caesarean delivery. Roles of ultrasonography in the prediction of LGA and macrosomia has been reported with mixed results.What do the results of this study add? The results showed that the incidence of LGA, by third-trimester ultrasound and at birth, were significantly increased in women with false-positive GCT. Multiparity, excessive weight gain and LGA by third-trimester ultrasound significantly increased the risk of LGA. Third-trimester ultrasonography had 47.1% sensitivity, 92.1% specificity and LR + and LR- of 5.96 and 0.57 in identifying LGA infants.What are the implications of these findings for clinical practice and/or further research? More intensive behavioural and dietary interventions, together with weight gain control and monitoring, may be needed in women with false-positive GCT to minimise the risk of LGA. Third trimester ultrasonographic examination might be helpful to detect and predict LGA at birth and should be included into routine clinical practice. Further studies that are more widely generalisable are needed to elucidate the relationship between false-positive GCT and adverse pregnancy outcomes and to investigate the benefits of ultrasonographic examination in the prediction of LGA and macrosomia.

Abnormal glucose tolerance and the 50-gram glucose challenge test in Cystic fibrosis

Diabetes has emerged as a major co-morbidity in cystic fibrosis (CF). The 75 g oral glucose tolerance test (OGTT) is used to screen for CF-related diabetes (CFRD) but is inconvenient, and adherence to screening is poor. The 50 g glucose challenge test (GCT) is shorter, performed non-fasting, and may serve to pre-screen the subset of individuals requiring confirmatory OGTT. We performed a pilot study in twenty-seven CF individuals across the glucose tolerance spectrum to test whether the GCT could identify subjects with abnormal glucose tolerance defined as 2-h OGTT glucose ≥7.8 mmol/L (2 h-AGT) or 1-h defined as 1-hr OGTT glucose ≥11.1 mmol/L (1 h-AGT). A GCT threshold of 8.1 mmol/L was 73% sensitive and 63% specific for 2hr-AGT and 80% sensitive and 65% specific for 1hr-AGT. Therefore, a screening GCT may reduce need for confirmatory OGTT for identifying AGT but a larger study is warranted to identify a robust cutoff for CFRD.

Pregnancy outcomes associated with an abnormal 50-g glucose screen during pregnancy: a systematic review and Meta-analysis

Objective: To assess the association between an abnormal 1-h 50-g glucose challenge test (GCT) followed by a normal 3-h 100-g glucose tolerance test (GTT) on fetal macrosomia and other adverse outcomes.Data sources: MEDLINE, Cochrane, clinicaltrials.gov, and Google Scholar were searched from inception to March 2019.Methods of study selection: Any studies reporting adverse perinatal and/or maternal outcomes in women with an abnormal 50-g 1-h glucose challenge test (GCT) followed by a normal 3-h, 100-g glucose tolerance test (GTT) were included. Studies were critically appraised by three independent reviewers. Outcomes included fetal macrosomia, cesarean delivery, preeclampsia, birth weight, neonatal hypoglycemia, shoulder dystocia, NICU admission, respiratory morbidity, and low Apgar score. A random-effects model was employed to calculate pooled odds ratios (OR) for each outcome with their 95% confidence intervals (CI) and 95% predictive intervals (PI).Tabulation, integration, and results: We identified 30 studies comprising 18,067 patients with a normal 3-h GTT after an abnormal 1-h GCT (study group) and 117,091 patients with a normal 1-h, 50-g GCT (comparison group). Patients in the study group had an increased risk of macrosomia (OR 1.68, 95% CI 1.48-1.91, 27 studies, 132,027 patients), cesarean delivery (OR 1.39, 95% CI 1.30-1.48, 24 studies, 128,495 women), preeclampsia (OR 1.48, 95% CI 1.15-1.91, 17 studies, 110,930 patients), hypoglycemia (OR 1.43, CI 1.07-1.91) and shoulder dystocia (OR 1.52, 95% CI 1.09-2.12, 9 studies, 41,229 patients). Neonatal birth weight was significantly higher in the study group. The incidence of NICU admission, low Apgar score, and respiratory morbidity was similar in the two groups. Controlling for body mass index and 1-h glucose screen cut off did not alter these results.Conclusion: Even in the absence of gestational diabetes, patients who fail the GCT test are at mildly increased risk of maternal and neonatal morbidity including macrosomia, cesarean delivery, preeclampsia, and shoulder dystocia.

Relationship between 50-g glucose challenge test and large for gestational age infants among pregnant women without gestational diabetes

The study aimed to compare the incidence of large for gestational age (LGA) infants between women with a false positive and normal glucose challenge test (GCT), and to evaluate the factors associated with LGA. A total of 480 pregnant women at risk for gestational diabetes mellitus (GDM); 160 with a false positive GCT and 320 with normal GCT results were included. The incidence of LGA and other pregnancy outcomes were compared between the two groups. Possible associated factors for LGA were also evaluated. Women with a false positive GCT were significantly older and more likely to be multiparous. The incidence of LGA was comparable between the false positive and normal GCT groups (15.6% vs. 13.1%, p = .456). Other pregnancy outcomes were also comparable. Logistic regression analysis showed that pre-pregnancy underweight significantly reduced the risk of LGA (adjusted OR 0.25, 95% CI 0.07-0.87, p = .029) while a second trimester weight gain >7 kg significantly increased the risk of LGA (adjusted OR 3.13, 95% CI 1.67-5.89, p < .001). Impact Statement What is already known on this subject? Women with a false-positive GCT (abnormal GCT but normal OGTT) can be considered as having an early form of glucose intolerance which similar adverse outcomes to GDM could develop. Previous studies have reported that a mild maternal hyperglycaemia in the absence of GDM is associated with LGA, macrosomia, shoulder dystocia and a caesarean delivery. There is no current recommendation for any intervention or treatment among women with a false positive GCT. What the results of this study add? The results of this study showed that an incidence of LGA was not significantly increased in the false positive GCT groups and that other pregnancy outcomes were comparable. A pre-pregnancy underweight significantly reduced the risk of LGA while a second trimester weight gain >7 kg significantly increased the risk of LGA. What the implications are of these findings for clinical practice and/or further research? As a gestational weight gain is modifiable, behavioural and a dietary intervention as well as a close monitoring of the weight gain could help in lowering the risk of LGA, even in the absence of GDM. Further studies which are more widely generalisable are needed to elucidate the relationship between 50 g GCT and the adverse outcomes and to investigate the benefits of a specific intervention among this specific group of women.

The identification and treatment of women with hyperglycaemia in pregnancy: an analysis of individual participant data, systematic reviews, meta-analyses and an economic evaluation

BACKGROUND

Gestational diabetes mellitus (GDM) is associated with a higher risk of important adverse outcomes. Practice varies and the best strategy for identifying and treating GDM is unclear.

AIM

To estimate the clinical effectiveness and cost-effectiveness of strategies for identifying and treating women with GDM.

METHODS

We analysed individual participant data (IPD) from birth cohorts and conducted systematic reviews to estimate the association of maternal glucose levels with adverse perinatal outcomes; GDM prevalence; maternal characteristics/risk factors for GDM; and the effectiveness and costs of treatments. The cost-effectiveness of various strategies was estimated using a decision tree model, along with a value of information analysis to assess where future research might be worthwhile. Detailed systematic searches of MEDLINE^® and MEDLINE In-Process & Other Non-Indexed Citations^®, EMBASE, Cumulative Index to Nursing and Allied Health Literature Plus, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, Health Technology Assessment database, NHS Economic Evaluation Database, Maternity and Infant Care database and the Cochrane Methodology Register were undertaken from inception up to October 2014.

RESULTS

We identified 58 studies examining maternal glucose levels and outcome associations. Analyses using IPD alone and the systematic review demonstrated continuous linear associations of fasting and post-load glucose levels with adverse perinatal outcomes, with no clear threshold below which there is no increased risk. Using IPD, we estimated glucose thresholds to identify infants at high risk of being born large for gestational age or with high adiposity; for South Asian (SA) women these thresholds were fasting and post-load glucose levels of 5.2 mmol/l and 7.2 mmol/l, respectively and for white British (WB) women they were 5.4 and 7.5 mmol/l, respectively. Prevalence using IPD and published data varied from 1.2% to 24.2% (depending on criteria and population) and was consistently two to three times higher in SA women than in WB women. Lowering thresholds to identify GDM, particularly in women of SA origin, identifies more women at risk, but increases costs. Maternal characteristics did not accurately identify women with GDM; there was limited evidence that in some populations risk factors may be useful for identifying low-risk women. Dietary modification additional to routine care reduced the risk of most adverse perinatal outcomes. Metformin (Glucophage,^® Teva UK Ltd, Eastbourne, UK) and insulin were more effective than glibenclamide (Aurobindo Pharma - Milpharm Ltd, South Ruislip, Middlesex, UK). For all strategies to identify and treat GDM, the costs exceeded the health benefits. A policy of no screening/testing or treatment offered the maximum expected net monetary benefit (NMB) of £1184 at a cost-effectiveness threshold of £20,000 per quality-adjusted life-year (QALY). The NMB for the three best-performing strategies in each category (screen only, then treat; screen, test, then treat; and test all, then treat) ranged between -£1197 and -£1210. Further research to reduce uncertainty around potential longer-term benefits for the mothers and offspring, find ways of improving the accuracy of identifying women with GDM, and reduce costs of identification and treatment would be worthwhile.

LIMITATIONS

We did not have access to IPD from populations in the UK outside of England. Few observational studies reported longer-term associations, and treatment trials have generally reported only perinatal outcomes.

CONCLUSIONS

Using the national standard cost-effectiveness threshold of £20,000 per QALY it is not cost-effective to routinely identify pregnant women for treatment of hyperglycaemia. Further research to provide evidence on longer-term outcomes, and more cost-effective ways to detect and treat GDM, would be valuable.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013004608.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Clinical significance of a false positive glucose challenge test in patients with a high body mass index

OBJECTIVE

To determine if there is an increased maternal or neonatal morbidity in overweight and obese patients with a false positive glucose challenge test (GCT).

METHODS

Patients with a body mass index (BMI) ≥25.0 at registration were included in this prospective 36-month study. The study cohort consisted of patients with a false positive (FP) GCT, with two comparison cohorts: those with a (1) screen negative (SN) GCT result and (2) true positive (TP) GCT result. Risks were reported as odd ratios with 95% confidence intervals, with a P<0.05 considered as significant.

RESULTS

There were 60 patients in the FP cohort, 106 in the SN cohort, and 64 in the TP cohort. When the BMI of the FP cohort was compared with either the SN cohort or TP cohort, differences were non-significant (SN 32.3 vs. FP 33.3 kg/m2, P=0.067) and (FP 33.3 vs. TP 34.4 kg/m2, P=0.303). When comparing the FP cohort to the SN cohort, patients in the FP group had significantly more gestational hypertension and pre-eclampsia. There was a trend towards delivering large for gestational weight infants and an infant ≥4000 g in the FP cohort, but this fell short of reaching statistical significance. When comparing the FP to TP cohorts, rates of gestational hypertension, pre-eclampsia, and infants ≥4000 g were similar; however, neonatal morbidity was increased in the TP group.

CONCLUSIONS

Overweight and obese patients with a FP glucose challenge screen are more likely to have adverse maternal outcomes. Neonatal morbidity was not increased.

Recurrent Shoulder Dystocia: Risk Factors and Counseling

A prior history of delivery complicated by shoulder dystocia confers a 6-fold to nearly 30-fold increased risk of shoulder dystocia recurrence in a subsequent vaginal delivery, with most reported rates between 12% and 17%. Whereas prevention of shoulder dystocia in the general population is neither feasible nor cost-effective, directing intervention efforts at the particular subgroup of women with a prior history of shoulder dystocia has merit. Potentially modifiable risk factors and individualized management strategies that may reduce shoulder dystocia recurrence and its associated significant morbidities are reviewed.

The association between maternal hyperglycemia and perinatal outcomes in gestational diabetes mellitus patients: A retrospective cohort study

Pregnancies complicated by gestational diabetes mellitus (GDM) are associated with increased risks of adverse maternal and fetal outcomes. The risks of adverse pregnancy outcomes differ depending on the glucose values among GDM patients. For accurate and effective prenatal counseling, it is necessary to understand the relationship between different maternal hyperglycemia values and the severity of adverse outcomes. With this objective, this study reexamines the relationship between maternal hyperglycemia versus maternal and perinatal outcomes in GDM patients. For this study, maternal hyperglycemia was diagnosed using the 2-step diagnostic approach.Medical records of 3434 pregnant women, who received the 50-g glucose challenge test (GCT) between March 2001 and April 2013, were reviewed. As a result, 307 patients were diagnosed with GDM, and they were divided into 2 groups according to their fasting glucose levels. A total of 171 patients had normal fasting glucose level (<95 mg/dL), and 136 patients had abnormal fasting glucose level (≥95 mg/dL). The 50-g GCT results were subdivided by 20-unit increments (140-159, n = 123; 160-179, n = 84; 180-199, n = 50; and ≥200, n = 50), and the maternal and perinatal outcomes were compared against the normal 50-g GCT group (n = 307).Maternal fasting blood glucose (FBG) level showed clear association with adverse perinatal outcomes. The odds ratio (OR) of macrosomia was 6.72 (95% CI: 2.59-17.49, P < 0.001) between the 2 groups. The ORs of large for gestational age (LGA) and neonatal hypoglycemia were 3.75 (95% CI: 1.97-7.12, P < 0.001) and 1.65 (95% CI: 0.79-3.43, P  =  0.183), respectively. Also, the results of the 50-g GCT for each category showed strong association with increased risks of adverse perinatal outcomes compared to the normal 50-g GCT group. The OR of macrosomia (up to 20.31-fold), LGA (up to 6.15-fold), and neonatal hypoglycemia (up to 84.00-fold) increased with increasing 50-g GCT result.

Pregnancy Hyperglycaemia and Risk of Prenatal and Postpartum Depressive Symptoms

BACKGROUND

Glucose dysregulation in pregnancy may affect maternal depressive symptoms during the prenatal and postpartum periods via both physiologic and psychological pathways.

METHODS

During mid-pregnancy, a combination of 50-g 1-h non-fasting glucose challenge test (GCT) and 100-g 3-h fasting oral glucose tolerance test was used to determine pregnancy glycaemic status among women participating in Project Viva: normal glucose tolerance (NGT), isolated hyperglycaemia (IHG), impaired glucose tolerance (IGT) and gestational diabetes mellitus (GDM). Using the Edinburgh Postnatal Depression Scale (EPDS), we assessed depressive symptoms at mid-pregnancy and again at 6 months postpartum. We used logistic regression, adjusted for sociodemographic, anthropometric and lifestyle factors, to estimate the odds of elevated prenatal and postpartum depressive symptoms (EPDS ≥ 13 on 0-30 scale) in relation to GCT glucose levels and GDM status in separate models.

RESULTS

A total of 9.6% of women showed prenatal and 8.4% postpartum depressive symptoms. Women with higher GCT glucose levels were at greater odds of elevated prenatal depressive symptoms [multivariable-adjusted odds ratio (OR) per standard deviation (SD) increase in glucose levels (27 mg/dL): 1.25; 95%: 1.07, 1.48]. Compared with NGT women, the association appeared stronger among women with IHG [OR: 1.80; 95% confidence interval (CI): 1.08, 3.00] than among those with GDM (OR: 1.45; 95% CI: 0.72, 2.91) or IGT (OR: 1.43; 95% CI: 0.59, 3.46). Neither glucose levels assessed from the GCT nor pregnancy glycaemic status were significantly associated with elevated postpartum depressive symptoms.

CONCLUSION

Pregnancy hyperglycaemia was cross-sectionally associated with higher risk of prenatal depressive symptoms, but not with postpartum depressive symptoms.

Association between Prenatal One-Hour Glucose Challenge Test Values and Delivery Mode in Nondiabetic, Pregnant Black Women

Objective. We examined the association between 1-hour glucose challenge test (GCT) values and risk of caesarean section. Study Design. A prospective cohort study recruited 203 pregnant Black women to participate. At ~28 weeks of gestation, participants underwent a routine 1-hour 50 g GCT to screen for gestational diabetes mellitus. Logistic regression was used to examine the association between 1-hour GCT value and delivery mode. Results. Of the 158 participants included, 53 (33.5%) delivered via C-section; the majority (n = 29; 54.7%) were nulliparous. Mean 1-hour GCT values were slightly, but not significantly, higher among women delivering via C-section; versus vaginally (107.8 ± 20.7 versus 102.4 ± 21.5 mg/dL, resp.; P = 0.13). After stratifying by parity and adjusting for maternal age, previous C-section, and prepregnancy body mass index, 1-hour GCT value was significantly associated with increased risk of C-section among parous women (OR per 1 mg/dL increase in GCT value = 1.05; 95% CI OR: 1.00, 1.05; P = 0.045). Conclusion. Even slightly elevated 1-hour 50 g GCT values may be associated with delivery mode among parous Black women.

Diagnostic thresholds for gestational diabetes and their impact on pregnancy outcomes: a systematic review

AIMS

To assess different diagnostic thresholds for gestational diabetes on outcomes for mothers and their offspring in the absence of treatment for gestational diabetes. This information was used to inform a National Institutes of Health consensus conference on diagnosing gestational diabetes.

METHODS

We searched 15 electronic databases from 1995 to May 2012. Study selection was conducted independently by two reviewers. Randomized controlled trials or cohort studies were eligible if they involved women without known pre-existing diabetes mellitus and who did not undergo treatment for gestational diabetes. One reviewer extracted, and a second reviewer verified, data for accuracy. Two reviewers independently assessed methodological quality.

RESULTS

Thirty-eight studies were included. Three large, methodologically strong studies showed a continuous positive relationship between increasing glucose levels and the incidence of Caesarean section and macrosomia. When data were examined categorically (i.e. women meeting or not meeting specific diagnostic thresholds), women with gestational diabetes across all glucose criteria had significantly more Caesarean sections, shoulder dystocia, macrosomia (except for International Association of Diabetes in Pregnancy Study Groups' criteria) and large for gestational age. Higher glucose thresholds did not consistently demonstrate greater risk for all outcomes.

CONCLUSIONS

Higher glucose thresholds did not consistently demonstrate greater risk, possibly because studies did not compare mutually exclusive groups of women. A pragmatic approach for diagnosis of gestational diabetes using Hyperglycemia and Adverse Pregnancy Outcome Study odds ratio 2.0 thresholds warrants further consideration until additional analysis of the data comparing mutually exclusive groups of women is provided and large randomized controlled trials investigating different diagnostic and treatment thresholds are completed.

Objectively measured sleep duration and hyperglycemia in pregnancy

OBJECTIVE

Our primary purpose was to assess the impact of objectively measured nighttime sleep duration on gestational glucose tolerance. We additionally examined associations of objectively measured daytime sleep duration and nap frequency on maternal glycemic control.

METHODS

Sixty-three urban, low-income, pregnant women wore wrist actigraphs for an average of 6 full days in mid-pregnancy prior to screening for hyperglycemia using the 1-h oral glucose tolerance test (OGTT). Correlations of nighttime and daytime sleep durations with 1-h OGTT values were analyzed. Multivariable logistic regression was used to evaluate independent associations between sleep parameters and hyperglycemia, defined as 1-h OGTT values ≥130 mg/dL.

RESULTS

Mean nighttime sleep duration was 6.9±0.9 h which was inversely correlated with 1-h OGTT values (r=-0.28, P=.03). Shorter nighttime sleep was associated with hyperglycemia, even after controlling for age and body mass index (adjusted odds ratio [OR], 0.2 [95% confidence interval {CI}, 0.1-0.8]). There were no associations of daytime sleep duration and nap frequency with 1-h OGTT values or hyperglycemia.

CONCLUSIONS

Using objective measures of maternal sleep time, we found that women with shorter nighttime sleep durations had an increased risk for gestational hyperglycemia. Larger prospective studies are needed to confirm our negative daytime sleep findings.

Placental growth factor as a new marker for predicting abnormal glucose challenge test results

BACKGROUND

To differentiate placental growth factor (PlGF) levels in pregnancies with normal and abnormal glucose challenge test (GCT) results.

METHODS

A total of 94 pregnant women underwent a 50 -g GCT as part of our routine antenatal screening protocol from September 2011 to January 2012. The patients were divided into three groups: (i) normal GCT, (ii) abnormal GCT and (iii) gestational diabetes mellitus (GDM) based on the screening results for gestational diabetes. The main outcome measure of the study was the relationship between PlGF and GCT results in non-diabetic pregnancies. The Kolmogorov-Smirnov test was used to check the normality of the variables' distributions. The Kruskal-Wallis and analysis of variance tests (Tukey's test) were used to analyze the qualitative parameters.

RESULTS

There were 53 (56.4%), 22 (23.4%) and 19 (20.2%) patients in the normal GCT, abnormal GCT and GDM groups, respectively. The PlGF level in the abnormal GCT group was 518 ± 307.6 pg/mL, which was the highest level in the study population, and there was a statistically significant difference compared with the other groups (p = 0.006). There were no statistically significant differences with respect to fetal birth weight among the three groups in our study.

CONCLUSION

PlGF can be used as a laboratory marker to predict which patients will have abnormal GCT results.

Relationship between 1-hour glucose challenge test results and perinatal outcomes

OBJECTIVE

To estimate the relationship between 1-hour 50 g glucose challenge test values and perinatal outcomes.

METHODS

This was a secondary analysis of data from a multicenter treatment trial of mild gestational diabetes mellitus. Women with glucose challenge test values of 135-199 mg/dL completed a 3-hour oral glucose tolerance test. Mild gestational diabetes mellitus was defined as fasting glucose less than 95 mg/dL and two or more abnormal oral glucose tolerance test values: 1-hour 180 mg/dL or more; 2-hour 155 mg/dL or more; and 3-hour 140 mg/dL or more. Our study included untreated women with glucose challenge test values of 135-139 mg/dL and 140-199 mg/dL and a comparison group with values less than 120 mg/dL. Primary outcomes included a perinatal composite (stillbirth, neonatal death, hypoglycemia, hyperbilirubinemia, neonatal hyperinsulinemia, and birth trauma), large for gestational age (LGA, birth weight above the 90 percentile based on sex-specific and race-specific norms), and macrosomia (greater than 4,000 g).

RESULTS

There were 436 women with glucose challenge test values less than 120 mg/dL and 1,403 with values of 135 mg/dL or more (135-139, n=135; 140-199, n=1,268). The composite perinatal outcome occurred in 25.6% of those with glucose challenge test values less than 120 mg/dL compared with 21.1% for values of 135-139 mg/dL and 35.3% for values of 140-199 mg/dL. Rates of LGA by group were 6.6%, 6.8%, and 12.4%, respectively. Rates of macrosomia by group were 7.8%, 6.1%, and 12.1%, respectively. Compared with glucose challenge test values less than 120 mg/dL, the adjusted odds ratios (ORs) (95% confidence intervals [CIs]) for values of 140-199 mg/dL were 1.48 (1.14-1.93) for the composite outcome, 1.97 (1.29-3.11) for LGA, and 1.61 (1.07-2.49) for macrosomia. For glucose challenge test values of 135-139 mg/dL, adjusted ORs and 95% CIs were 0.75 (0.45-1.21), 1.04 (0.44-2.24), and 0.75 (0.30-1.66), respectively. The subcategories with glucose challenge test values of 140-144 mg/dL and 145-149 mg/dL also were associated with an increase in selected outcomes when compared with those with values less than 120 mg/dL.

CONCLUSIONS

Glucose challenge test values of 135-139 mg/dL were not associated with adverse outcomes compared with values less than 120 mg/dL; however, glucose challenge test values of 140 mg/dL or more were associated with an increase in odds of the composite perinatal outcome, LGA, and macrosomia.

Association between adiponectin and tumor necrosis factor-alpha levels at eight to fourteen weeks gestation and maternal glucose tolerance: the Parity, Inflammation, and Diabetes Study

OBJECTIVE

Inflammation may influence gestational hyperglycemia, but to date, the data from observational studies is largely limited to results from the third trimester of pregnancy. Our objective was to evaluate first trimester adipocytokine levels. We sought to determine whether first trimester adiponectin and tumor necrosis factor-alpha (TNF)-alpha concentrations were independently associated and predictive of maternal glucose tolerance, as measured by the 1-hour glucose challenge test (GCT), after adjustment for maternal lifestyle behaviors and body mass index (BMI).

MATERIAL AND METHODS

Prospective study of pregnant women (n=211) enrolled in the Parity, Inflammation, and Diabetes Study. Nonfasting serum levels of adiponectin and TNF-r2 were measured at 8-14 weeks of pregnancy. GCT results were abstracted from electronic prenatal records. Multiple linear regression models were developed to determine the association of adiponectin and TNF-r2 levels with response to the GCT, adjusting for demographics, pregravid dietary intake and physical activity, first trimester BMI, and gestational weight gain.

RESULTS

At baseline, higher adiponectin concentrations were inversely and statistically significantly associated with maternal response to the GCT [regression coefficient (β) -0.68; 95% confidence interval (CI): -1.29, -0.06). Adjustment for lifestyle factors did not alter the association of adiponectin with the GCT (β -0.74; 95% CI: -1.43, -0.05). After adjustment for first trimester BMI, the association of adiponectin was attenuated and no longer significant (β -0.46; 95% CI: -1.15, 0.24). TNF-r2 levels were not associated with the GCT (β -0.003; 95% CI: -0.011, 0.005).

CONCLUSIONS

First trimester adiponectin levels are not predictive of the 1-hour GCT response, but may be a marker for the effect of maternal BMI on glucose response to the GCT.

The association between low 50 g glucose challenge test result and fetal growth restriction

OBJECTIVE

To determine whether a low-GCT result is predictive of low birthweight and to identify the lower GCT threshold for prediction of fetal growth restriction.

METHODS

A retrospective cohort study of 12,899 women who underwent a GCT (24-28 weeks). Women with a low-GCT result (<10th percentile (70 mg/dL) were compared to women with normal-GCT result (70-140 mg/dL). ROC analysis was used to determine the optimal lower GCT threshold for the prediction of growth restriction.

RESULTS

Women in the low GCT had significant lower rates of cesarean delivery (18.7% versus 22.5%), shoulder dystocia (0.0% versus 0.3%), mean birthweight (3096 ± 576 versus 3163 ± 545) and birthweight percentile (49.1 ± 27.0 versus 53.1 ± 26.7) and significant higher rates of birthweight <2500 g (11.3% versus 8.5%), below the 10th percentile (8.3% versus 6.5%) and 3rd percentile (2.3% versus 1.4%). Low GCT was independently associated with an increased risk for birthweight <2500 g (OR = 1.6, 1.2-2.0), birthweight <10th percentile (OR = 1.3, 1.1-1.6), birthweight <3rd percentile (OR = 1.7, 1.2-2.5) and neonatal hypoglycemia (OR = 1.4, 1.02-2.0). The optimal GCT threshold for the prediction of birthweight <10th percentile was 88.5 mg/dL (sensitivity 48.5%, specificity 58.1%).

CONCLUSION

Low-GCT result is independently associated with low birthweight and can be used in combination with additional factors for the prediction of fetal growth restriction.

Is abnormal 50-g glucose-challenge testing an independent predictor of adverse pregnancy outcome?

OBJECTIVE

To determine whether an abnormal 50-g glucose-challenge test (GCT) is independently associated with adverse pregnancy outcome.

METHODS

A retrospective study of women with abnormal GCT (>140 mg/dL) but normal subsequent 100-g oral glucose-tolerance test (OGTT). Pregnancy outcome was compared with that of women with normal GCT (<140 mg/dL).

RESULTS

Of the 79,153 women delivered during the study period, the results of the GCT were available for 14,268. Of these, 809 (5.7%) had an abnormal GCT and normal OGTT and were eligible for the study group. An abnormal GCT was independently associated with an increased risk for macrosomia (odds ratio [OR] = 2.0, 95% CI: 1.5-2.7), large for gestational age (OR = 1.6, 95% CI: 1.3-2.0), cesarean section (OR = 1.3, 95% CI: 1.1-1.6), respiratory morbidity (OR = 1.6, 95% CI: 1.1-2.7) and neonatal hypoglycemia (OR = 1.8, 95% CI: 1.1-3.2). In contrast, an abnormal GCT was associated with decreased risk for preterm delivery at less than 37 weeks (OR = 0.7, 95% CI: 0.5-0.9) and 34 weeks (OR = 0.3, 95% CI: 0.1-0.6). The association between abnormal GCT and adverse pregnancy outcome was unrelated to the degree of GCT abnormality except for cases in which the GCT was extremely high (≥180 mg/dL).

CONCLUSION

Women with abnormal-GCT result are at increased risk for adverse pregnancy outcome even in the presence of a normal subsequent OGTT.

Interventions for pregnant women with hyperglycaemia not meeting gestational diabetes and type 2 diabetes diagnostic criteria

BACKGROUND

Pregnancy hyperglycaemia without meeting gestational diabetes mellitus (GDM) diagnostic criteria affects a significant proportion of pregnant women each year. It is associated with a range of adverse pregnancy outcomes. Although intensive management for women with GDM has been proven beneficial for women and their babies, there is little known about the effects of treating women with hyperglycaemia who do not meet diagnostic criteria for GDM and type 2 diabetes (T2DM).

OBJECTIVES

To assess the effects of different types of management strategies for pregnant women with hyperglycaemia not meeting diagnostic criteria for GDM and T2DM (referred as borderline GDM in this review).

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 September 2011).

SELECTION CRITERIA

Randomised and cluster-randomised trials comparing alternative management strategies for women with borderline GDM.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility, extracted data and assessed risk of bias of included studies. Data were checked for accuracy.

MAIN RESULTS

We included four trials involving 543 women and their babies (but only data from 521 women and their babies is included in our analyses). Three of the four included studies had moderate to high risk of bias and one study was at low to moderate risk of bias. Babies born to women receiving management for borderline GDM (generally dietary counselling and metabolic monitoring) were less likely to be macrosomic (birthweight greater than 4000 g) (three trials, 438 infants, risk ratio (RR) 0.38, 95% confidence interval (CI) 0.19 to 0.74) or large-for-gestational (LGA) age (three trials, 438 infants, RR 0.37, 95% CI 0.20 to 0.66) when compared with those born to women in the routine care group. There were no significant differences in rates of caesarean section (three trials, 509 women, RR 0.93, 95% CI 0.68 to 1.27) and operative vaginal birth (one trial, 83 women, RR 1.37, 95% CI 0.20 to 9.27) between the two groups.

AUTHORS' CONCLUSIONS

This review found interventions including providing dietary advice and blood glucose level monitoring for women with pregnancy hyperglycaemia not meeting GDM and T2DM diagnostic criteria helped reduce the number of macrosomic and LGA babies without increasing caesarean section and operative vaginal birth rates. It is important to notice that the results of this review were based on four small randomised trials with moderate to high risk of bias without follow-up outcomes for both women and their babies.

Reducing the risk of shoulder dystocia and associated brachial plexus injury

Despite persisting controversy over shoulder dystocia prediction, prevention, and injury causation, the authors find considerable evidence in recent research in the field to recommend additional guidelines beyond the current American College of Obstetricians and Gynecologists and Royal College of Obstetricians and Gynecologists guidelines to improve clinical practice in managing patients at risk for experiencing shoulder dystocia. In this article, the authors offer health care providers information, practical direction, and advice on how to limit shoulder dystocia risk and, more importantly, to reduce adverse outcome risk.

Contribution of first trimester fasting plasma insulin levels to the incidence of glucose intolerance in later pregnancy: Tanaka women's clinic study

AIMS

To clarify risk factors predictive of glucose intolerance in later pregnancy.

METHODS

We prospectively studied 509 pregnant women who visited the obstetrics clinic in Tokyo prior to week 13 of gestation, between September 2008 and January 2010. Biochemical parameters were measured in fasting plasma samples collected at week 8.0 ± 2.0 of gestation. A 50 g glucose challenge test (GCT) was performed between weeks 26 and 29: plasma glucose levels ≥ 7.8 mmol/l 1h after ingestion indicated a positive GCT. Logistic regression was performed, adjusting for relevant covariates.

RESULTS

We identified 114 patients with positive GCTs, including 8 with gestational diabetes mellitus (GDM). After correcting for baseline body mass index, only the homeostasis model assessment of insulin resistance value remained a significant predictor of GCT positivity (OR 2.07; 1.21-3.55). We identified threshold values of fasting plasma glucose (FPG) ≥ 3.66 mmol/l and fasting plasma insulin (FPI) ≥ 36.69 pmol/l as indicative of a higher risk of positive GCT (OR 2.38; 1.49-3.80).

CONCLUSIONS

First trimester FPI levels improve the predictive ability of FPG level on subsequent GCT positivity.

Definition, epidemiology, risk factors

Gestational diabetes mellitus is defined as glucose intolerance that begins or is first recognized during pregnancy. Its prevalence, generally situated between 2-6%, may reach 10-20% in high-risk populations, with an increasing trend across most racial/ethnic groups studied. Among traditional risk factors, previous gestational diabetes, advanced maternal age and obesity have the highest impact on gestational diabetes risk. Racial/ethnic origin and family history of type 2 diabetes have a significant but moderate impact (except for type 2 diabetes in siblings). Several non traditional factors have been recently characterized, either physiological (low birthweight and short maternal height) or pathological (polycystic ovaries). The multiplicity of risk factors and their interactions results in a low reliability of risk prediction on an individual basis.

Carpenter-Coustan criteria compared with the national diabetes data group thresholds for gestational diabetes mellitus

OBJECTIVE

To examine perinatal outcomes in women who would meet the diagnostic criteria for gestational diabetes mellitus (GDM) according to the Carpenter and Coustan but not by the National Diabetes Data Group (NDDG) thresholds.

METHODS

This is a retrospective cohort study of women screened for GDM between January 1988 and December 2001. During the study period, only women who were diagnosed with GDM by the NDDG criteria received counseling and treatment. Women diagnosed with GDM according to the Carpenter and Coustan thresholds but not by the NDDG criteria were compared with women without GDM by either criteria. Perinatal outcomes were examined using chi test and multivariable logistic regression analyses.

RESULTS

Among the 14,693 women screened for GDM, 753 (5.1%) would have GDM diagnosed by the Carpenter and Coustan criteria and 480 (3.3%) by the NDDG criteria only, giving 273 (1.9%) women as the study group. Compared with women without GDM, women with GDM by the Carpenter and Coustan but not by the NDDG criteria had higher odds of cesarean delivery (OR 1.44, 95% confidence interval [CI] 1.01-2.07), operative vaginal delivery (OR 1.72, 95% CI 1.20-2.46), birth weight greater than 4,500 g (OR 4.47, 95% CI 2.26-8.86), and shoulder dystocia (OR 2.24, 95% CI 1.03-4.88).

CONCLUSION

Women diagnosed with GDM by the Carpenter and Coustan criteria but not by the NDDG criteria had higher risk of operative deliveries, macrosomia, and shoulder dystocia. We recommend using the Carpenter and Coustan diagnostic thresholds for GDM, because these diagnostic criteria are more sensitive than the NDDG criteria.

LEVEL OF EVIDENCE

II.

An abnormal screening glucose challenge test in pregnancy predicts postpartum metabolic dysfunction, even when the antepartum oral glucose tolerance test is normal

OBJECTIVE

In pregnancy, a normal result on the oral glucose tolerance test (OGTT) that follows an abnormal screening glucose challenge test (GCT) is considered a reassuring finding, requiring no further intervention. The obstetrical and metabolic implications of this presentation, however, have not been well studied. Thus, we sought to characterize the obstetrical and postpartum metabolic significance of an abnormal GCT in women with normal glucose tolerance (NGT) on antepartum OGTT.

DESIGN/PATIENTS/MEASUREMENTS

A total of 259 women with NGT on antepartum OGTT (166 with an abnormal GCT and 93 with a normal GCT) underwent (i) metabolic evaluation in pregnancy, (ii) assessment of obstetrical outcome at delivery and (iii) repeat metabolic characterization by OGTT at 3 months postpartum.

RESULTS

Neither infant birthweight nor Caesarean section rate differed between the abnormal GCT and normal GCT groups. At 3 months postpartum, however, compared to the normal GCT group, the abnormal GCT group exhibited greater glycaemia (mean area under the glucose curve (AUC(gluc)) 19.6 vs. 18.3, P = 0.0021), lower insulin sensitivity (median insulin sensitivity index (IS(OGTT)) 9.5 vs. 11.3, P = 0.0243) and poorer beta-cell function (median insulinogenic index/Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) 9.8 vs. 14.1, P = 0.0013). On multiple linear regression analyses, an abnormal GCT emerged as (i) the strongest independent predictor of postpartum AUC(gluc) (t = 2.77, P = 0.006) and (ii) the strongest independent negative predictor of log insulinogenic index/HOMA-IR (t = -2.36, P = 0.0191). Furthermore, the GCT was the antepartum parameter that best predicted postpartum pre-diabetes (area under the receiver operating characteristic curve (AROC) = 0.754).

CONCLUSIONS

An abnormal antepartum GCT, even when followed by a normal OGTT, is associated with postpartum glycaemia and beta-cell dysfunction, factors that may portend an increased future risk of diabetes in this patient population.

Abdominal visceral adiposity in the first trimester predicts glucose intolerance in later pregnancy

OBJECTIVE

To assess whether abdominal adiposity in early pregnancy is associated with a higher risk of glucose intolerance at a later gestational stage.

RESEARCH DESIGN AND METHODS

Subcutaneous and visceral fat was measured with ultrasonography at approximately 12 weeks' gestation. A 50-g glucose challenge test (GCT) was performed between 24 and 28 weeks' gestation. The risk of having a positive GCT (>or=7.8 mmol/l) was determined in association with subcutaneous and visceral adipose tissue depths above their respective upper-quartile values relative to their bottom three quartile values.

RESULTS

Sixty-two women underwent GCTs. A visceral adipose tissue depth above the upper quartile value was significantly associated with a positive GCT in later pregnancy (adjusted odds ratio 16.9 [95% CI 1.5-194.6]). No associations were seen for subcutaneous adipose tissue.

CONCLUSIONS

Measurement of visceral adipose tissue depth in early pregnancy may be associated with glucose intolerance later in pregnancy.

Hyperglycaemia following glucose challenge test during pregnancy: when can a screening test become diagnostic?

OBJECTIVE

The 50g-glucose challenge test (GCT) is commonly used for screening of gestational diabetes (GDM) in low risk pregnant women. If elevated, glucose tolerance test is performed to confirm the diagnosis. In this study, we evaluated whether GCT alone is sufficient to diagnose GDM when the GCT result is very elevated.

RESEARCH DESIGN AND METHODS

Using a database of 62877 pregnancies over 10 years, the positive predictive value (PPV) of GCT for GDM was assessed using different GCT cut-off values.

RESULTS

At a glucose cut-off value of 11 mmol/l, the PPV for GDM was 85.3%, based on the subsequent GTT. This increased to 95.3% when the cut-off was 12 mmol/l. Furthermore, the PPV was consistently higher when GCT was performed in the morning.

CONCLUSION

We concluded that the diagnosis of GDM can be made when the glucose level following GCT is very elevated, and GTT need not to be performed for confirmation of GDM. The timing of GCT also affected PPV for GDM, and has implications on the diagnostic value of the test.

The 50-g glucose challenge test and pregnancy outcome in a multiethnic Asian population at high risk for gestational diabetes

OBJECTIVE

To evaluate the 50-g glucose challenge test (GCT) on pregnancy outcome in a multiethnic Asian population at high risk for gestational diabetes (GDM).

METHODS

GCT was positive if the 1-hour plasma glucose level was >or=7.2 mmol/L. GDM was diagnosed by a 75-g glucose tolerance test using WHO (1999) criteria. Of the 1368 women enrolled in the study, 892 were GCT negative, 308 were GCT false-positive, and 168 had GDM. Pregnancy outcomes were extracted from hospital records. Multivariable logistic regression analysis was performed with GCT negative women as the reference group.

RESULTS

GCT false-positive status was associated with preterm birth (adjusted odds ratio [AOR] 2.1; 95% CI, 1.2-3.7) and postpartum hemorrhage (AOR 1.7; 95% CI, 1.0-2.7). GDM was associated with labor induction (AOR 5.0; 95% CI, 3.3-7.5), cesarean delivery (AOR 2.2; 95% CI, 1.6-3.2), postpartum hemorrhage (AOR 2.1; 95% CI, 1.2-3.7), and neonatal macrosomia (AOR 2.5; 95% CI, 1.0-6.0).

CONCLUSION

GCT false-positive women had an increased likelihood of an adverse pregnancy outcome. The role and threshold of the GCT needs re-evaluation.

Gestational diabetes: diagnosis and management

PURPOSE

To review the diagnosis and management of gestational diabetes.

EPIDEMIOLOGY

In the United States, approximately 2 to 5% of all pregnant women have gestational diabetes. Those women with a family history of type 2 diabetes mellitus, Asian or native American race, Latina ethnicity or obesity are at higher risk for developing gestational diabetes.

CONCLUSION

Women with gestational diabetes who are treated appropriately can achieve good outcomes in the majority of pregnancies. Frequent blood glucose monitoring, nutrition counseling and frequent physician contact allow for individualized care to achieve optimal outcomes. Such treatment includes diet, exercise and insulin. The use of oral hypoglycemic agents is controversial and there is some concern about worse maternal and neonatal outcomes as compared to treatment with insulin. Evolving technologies promise to provide more therapeutic options.

Modestly elevated glucose levels during pregnancy are associated with a higher risk of future diabetes among women without gestational diabetes mellitus

OBJECTIVE

To determine whether 1-h oral glucose challenge test (OGCT) or 3-h oral glucose tolerance test (OGTT) results below gestational diabetes mellitus (GDM) criteria are associated with developing diabetes.

RESEARCH DESIGN AND METHODS

A retrospective cohort study was performed among women without GDM who had a pregnancy OGCT (n = 24,780) or OGTT (n = 6,222). Subsequent diabetes was ascertained by ICD-9 codes or pharmacy or laboratory data over a median follow-up of 8.8 years.

RESULTS

Diabetes risk increased across OGCT quartiles: adjusted hazard ratio (HR) 1.67 (95% CI 1.07-2.61) for 5.4-6.2 mmol/l, 2.13 (1.39-3.25) for 6.3-7.3 mmol/l, and 3.60 (2.41-5.39) for >or=7.4 mmol/l compared with <or=5.3 mmol/l. Women with one abnormal OGTT result had a higher risk compared with those with normal values (HR 2.08 [95% CI 1.35-3.20]).

CONCLUSIONS

Women with modestly elevated glucose levels below the threshold for GDM had a higher risk for diabetes.