First-trimester glycosylated hemoglobin in women at high risk for gestational diabetes

Association of Early Pregnancy Values of Glycosylated Hemoglobin and the Development of Gestational Diabetes Mellitus

Introduction There is no consensus regarding screening and diagnostic methods for gestational diabetes mellitus (GDM). The present study aimed to evaluate the association between early pregnancy values of glycosylated hemoglobin and the development of gestational diabetes mellitus among pregnant women in a tertiary care hospital in eastern India. Methods The prospective cohort study included 200 pregnant women aged between 18 and 35 years in their first trimester (gestational age eight to 13 weeks) attending the antenatal clinics of the study hospital. A glycated hemoglobin (HbA1c) test and a 75-g oral glucose tolerance test (OGTT) test were done in all study participants in their first trimester. Pregnant women with HbA1c ≥6.5% and OGTT ≥140 mg/dl were excluded from the study. In other women, the second trimester (24-28 weeks) and the third trimester OGTT (32-34 weeks) were done to detect gestational diabetes mellitus. Data collection was initiated after the approval of the Information, Education, and Communication (IEC) and relevant authorities. Receiver operating characteristic (ROC) analysis was done to identify the cut-off value of HbA1c that predicted the development of GDM. Results The incidence of GDM was 33% among our study participants. The mean HbA1c was significantly higher among women who had GDM (5.4 ± 0.4%) as compared to those who did not develop GDM (4.9 ± 0.2%) (p<0.001). On ROC analysis of HbA1c values to predict the development of GDM, a cut-off value of HbA1c ≥5.25%, irrespective of risk status, was calculated to have 84.8% sensitivity and 62.7% specificity, and among the high-risk group, HbA1c ≥5.15% had 83.3% sensitivity and 97% specificity in predicting GDM. On stratified analysis, a moderately strong positive correlation was demonstrated between HbA1c values and OGTT in the second trimester in both high-risk and low-risk cohorts (p<0.05). Conclusion Based on the findings of the present study, HbA1c can be proposed to be a suitable biomarker for GDM prediction, probably not independently but rather as a component of a multi-marker approach for high- and low-risk pregnant groups.

Neighborhood Deprivation and Racial Disparities in Early Pregnancy Impaired Glucose Tolerance

OBJECTIVE

There is mounting evidence that neighborhoods contribute to perinatal health inequity. We aimed (1) to determine whether neighborhood deprivation (a composite marker of area-level poverty, education, and housing) is associated with early pregnancy impaired glucose intolerance (IGT) and pre-pregnancy obesity and (2) to quantify the extent to which neighborhood deprivation may explain racial disparities in IGT and obesity.

STUDY DESIGN

This was a retrospective cohort study of non-diabetic patients with singleton births ≥ 20 weeks' gestation from 1 January 2017-31 December 2019 in two Philadelphia hospitals. The primary outcome was IGT (HbA1c 5.7-6.4%) at <20 weeks' gestation. Addresses were geocoded and census tract neighborhood deprivation index (range 0-1, higher indicating more deprivation) was calculated. Mixed-effects logistic regression and causal mediation models adjusted for covariates were used.

RESULTS

Of the 10,642 patients who met the inclusion criteria, 49% self-identified as Black, 49% were Medicaid insured, 32% were obese, and 11% had IGT. There were large racial disparities in IGT (16% vs. 3%) and obesity (45% vs. 16%) among Black vs. White patients, respectively (p < 0.0001). Mean (SD) neighborhood deprivation was higher among Black (0.55 (0.10)) compared with White patients (0.36 (0.11)) (p < 0.0001). Neighborhood deprivation was associated with IGT and obesity in models adjusted for age, insurance, parity, and race (aOR 1.15, 95%CI: 1.07, 1.24 and aOR 1.39, 95%CI: 1.28, 1.52, respectively). Mediation analysis revealed that 6.7% (95%CI: 1.6%, 11.7%) of the Black-White disparity in IGT might be explained by neighborhood deprivation and 13.3% (95%CI: 10.7%, 16.7%) by obesity. Mediation analysis also suggested that 17.4% (95%CI: 12.0%, 22.4%) of the Black-White disparity in obesity may be explained by neighborhood deprivation.

CONCLUSION

Neighborhood deprivation may contribute to early pregnancy IGT and obesity-surrogate markers of periconceptional metabolic health in which there are large racial disparities. Investing in neighborhoods where Black patients live may improve perinatal health equity.

Trends in Screening for Diabetes in Early Pregnancy in the United States

Objective: The aim of this study was to characterize current diabetes screening practices in the first trimester of pregnancy in the United States, evaluate patient characteristics and risk factors associated with early diabetes screening, and compare perinatal outcomes by early diabetes screening. Methods: This was a retrospective cohort study of US medical claims data of persons diagnosed with a viable intrauterine pregnancy and who presented for care with private insurance before 14 weeks of gestation, without pre-existing pregestational diabetes, from the IBM MarketScan® database for the period January 1, 2016, to December 31, 2018. Univariate and multivariate analyses were used to evaluate perinatal outcomes. Results: A total of 400,588 pregnancies were identified as eligible for inclusion, with 18.0% of persons receiving early screening for diabetes. Of those with laboratory order claims, 53.1% underwent hemoglobin A1c testing, 30.0% underwent fasting glucose testing, and 16.9% underwent oral glucose tolerance testing. Compared with those who did not undergo early diabetes screening, those who did were more likely to be older; obese; having a history of gestational diabetes, chronic hypertension, polycystic ovarian syndrome, or hyperlipidemia; and having a family history of diabetes. In adjusted logistic regression, history of gestational diabetes (adjusted odds ratio 3.99; 95% confidence interval 3.73-4.26) had the strongest association with early diabetes screening. Adverse perinatal outcomes, including a higher rate of cesarean delivery, preterm delivery, preeclampsia, and gestational diabetes, occurred more frequently among women who underwent early diabetes screening. Conclusions: First-trimester early diabetes screening was mostly commonly performed by hemoglobin A1c evaluation, and persons who underwent early diabetes screening were more likely to experience adverse perinatal outcomes.

First-trimester glycosylated hemoglobin (HbA1c) and maternal characteristics in the prediction of gestational diabetes: An observational cohort study

INTRODUCTION

This study aimed to investigate the extent to which gestational diabetes mellitus (GDM) can be predicted in the first trimester by combining a marker of growing interest, glycosylated hemoglobin A1c (HbA1c), and maternal characteristics.

MATERIAL AND METHODS

This observational study was conducted in the outpatient obstetric department of our institution. The values of HbA1c and venous random plasma glucose were prospectively assessed in the first trimester of pregnancy. We determined maternal characteristics that were independent predictors from the regression analysis and calculated areas under the receiver-operating curves by combining the maternal age, body mass index, previous history of GDM, and first-degree family history for diabetes mellitus. Moreover we investigated the predictive capability of HbA1c to exclude GDM. Patients with a first-trimester HbA1c level of 6.5% (48 mmol/mol) or more were excluded. The study was registered at ClinicalTrials.gov ID: NCT02139254.

RESULTS

We included 785 cases with complete dataset. The prevalence of GDM was 14.7% (115/785). Those who developed GDM had significantly higher HbA1c and random plasma glucose values (p < 0.0001 and p = 0.0002, respectively). In addition, they had a higher body mass index, were more likely to have a history of GDM and/or a first-degree family history of diabetes. When these maternal characteristics were combined with the first-trimester HbA1c and random plasma glucose the combined area under the receiver operating characteristics curve was 0.76 (95% CI 0.70-0.81).

CONCLUSIONS

Our results indicate that HbA1c and random plasma glucose values combined with age, body mass index, and personal and family history, allow the identification of women in the first trimester who are at increased risk of developing GDM.

Diabetic Embryopathies

Diabetic embryopathy is defined as congenital anomalies that are linked to maternal diabetes. The association between diabetes and fetal, neonatal, and long-term complications is well-established. These complications include organ or structural maldevelopment, fetal growth abnormalities, and learning/psychiatric comorbidities. Recent studies have elucidated the pathophysiology behind these conditions and outlined new management approaches. Caudal regression syndrome, also known as sacral agenesis, is a well-known but less described complication of maternal diabetes. The purpose of this review is to summarize existing research on common neonatal morbidities in infants of mothers with diabetes with a focus on caudal regression syndrome and its long-term associations.

Early pregnancy glycaemia predicts postpartum diabetes mellitus

OBJECTIVE

To determine the association between early pregnancy glycaemia, as measured by glycosylated haemoglobin A1c (HbA1c) at the first prenatal visit, and persistent postpartum diabetes mellitus (DM).

STUDY DESIGN

All women first diagnosed with DM during pregnancy who had both HbA1c prior to 24 weeks and postpartum DM testing were included. The proportions of women with normal (<5.7%), prediabetic (5.7-6.4%) and elevated (≥6.5%) early HbA1c who tested positive for postpartum DM were compared. Test characteristics of HbA1c to predict persistent postpartum DM were calculated.

RESULTS

One hundred and twenty-one women met the study inclusion criteria. HbA1c was obtained at a median gestational age of 9 weeks. Twenty-two women (18.2%) had persistent postpartum DM, which was highly correlated with early HbA1c: 16 (73%) women had an elevated HbA1c, five (22.7%) women had a prediabetic HbA1c and only one (4.5%) woman had a normal HbA1c. Of 65 women with gestational DM and a normal early HbA1c, only one (1.5%) had persistent DM within the first year (negative predictive value 98.5%). Sixteen of 18 women with an elevated early HbA1c had persistent postpartum DM (positive predictive value 88.9%). These percentages were significant overall and between groups (p < 0.001). No clinical or demographic factors were highly predictive of postpartum DM.

CONCLUSIONS

Early pregnancy glycaemia, as measured by HbA1c at the first prenatal visit, is highly predictive of persistent postpartum DM, and may allow clinically important risk stratification to prioritize postpartum testing and care. Postpartum DM is rare amongst women with gestational DM who begin the pregnancy with a normal HbA1c, while postpartum DM is highly likely for those with an elevated HbA1c in early pregnancy. Nearly three-quarters of women who tested positive for DM post partum had an elevated HbA1c in early pregnancy, indicating that they had undiagnosed DM prior to conception.

Maternal metabolic factors and the association with gestational diabetes: A systematic review and meta-analysis

Gestational diabetes (GDM) is associated with several adverse outcomes for the mother and child. Higher levels of individual lipids are associated with risk of GDM and metabolic syndrome (MetS), a clustering of risk factors also increases risk for GDM. Metabolic factors can be modified by diet and lifestyle. This review comprehensively evaluates the association between MetS and its components, measured in early pregnancy, and risk for GDM. Databases (Cumulative Index to Nursing and Allied Health Literature, PubMed, Embase, and Cochrane Library) were searched from inception to 5 May 2021. Eligible studies included ≥1 metabolic factor (waist circumference, blood pressure, fasting plasma glucose (FPG), triglycerides, and high-density lipoprotein cholesterol), measured at <16 weeks' gestation. At least two authors independently screened potentially eligible studies. Heterogeneity was quantified using I² . Data were pooled by random-effects models and expressed as odds ratio and 95% confidence intervals (CIs). Of 7213 articles identified, 40 unique articles were included in meta-analysis. In analyses adjusting for maternal age and body mass index, GDM was increased with increasing FPG (odds ratios [OR] 1.92; 95% CI 1.39-2.64, k = 7 studies) or having MetS (OR 2.52; 1.65, 3.84, k = 3). Women with overweight (OR 2.17; 95% CI 1.89, 2.50, k = 12) or obesity (OR 4.34; 95% CI 2.79-6.74, k = 9) also were at increased risk for GDM. Early pregnancy assessment of glucose or the MetS, offers a potential opportunity to detect and treat individual risk factors as an approach towards GDM prevention; weight loss for pregnant women with overweight or obesity is not recommended. Systematic review registration: PROSPERO CRD42020199225.

The ability of a low value on an early GCT to identify women not needing repeat testing in the second trimester

OBJECTIVE

To evaluate the predictive value of a low early glucose challenge test (GCT) in ruling out a subsequent diagnosis of gestational diabetes in the second trimester.

METHODS

This was a retrospective cohort study of women at a single clinic who had a normal early GCT between 2016 and 2020. Patients who did not have repeat screening in the late second trimester were excluded. Demographic data were extracted from the record. The primary outcome was a normal GCT or glucose tolerance test in the late second trimester. Logistic regression and receiver operator curves (ROC) were performed to assess the ability of the early GCT value to predict subsequent normal glucose screening.

RESULTS

Of the 532 pregnant persons with normal early GCT, 62 (11.7%) were subsequently diagnosed with gestational diabetes in the second trimester. None of the patients (N = 56), who had a GCT value less than 80 mg/dL were diagnosed with gestational diabetes in the second trimester. The prediction of subsequent normal screening using the early GCT on a ROC plot produced an area under the curve (AUC) of 0.67, 95% CI (0.60-0.74). Adding age, prior history of gestational diabetes and family history of diabetes mellitus to the prediction, only improved the AUC to 0.75, 95% CI (0.66, 0.82).

CONCLUSION

Early GCT value was a fair predictor for normal second trimester glucose testing for gestational diabetes. However, high-risk patients with an early GCT value of less than 80 mg/dL may be able to forego repeat second trimester screening.

Use of oral glucose tolerance testing and HbA1c at 6-14 gestational weeks to predict gestational diabetes mellitus in high-risk women

PURPOSE

To study the prediction of gestational diabetes mellitus (GDM) in high-risk pregnant women by testing fasting blood glucose, 1-h(1hPG) and 2-h plasma glucose (2hPG) after an oral glucose tolerance test, and glycated hemoglobin (HbA1c) in early pregnancy (6-14 weeks).

METHODS

We recruited 1311 pregnant women at high risk for diabetes from the Obstetrics Clinic of Daxing District People's Hospital between June 2017 and December 2019. The tests performed during the first trimester included fasting blood glucose (FPG), HbA1c, and 75-g oral glucose tolerance test (OGTT) with 1hPG and 2hPG. Seventy-three pregnant women diagnosed with pregestational diabetes mellitus (PGDM) early in pregnancy and 36 who were missed in the second trimester were excluded. A total of 1202 women were followed up until 24-28 weeks for GDM. The receiver operating characteristic (ROC) and area under the ROC curve (AUC) were calculated to determine the predictive values of FPG, 1hPG, 2hPG, and HbA1c for GDM in early pregnancy in high-risk pregnant women.

RESULTS

The AUC for 1hPG for the prediction of GDM in high-risk pregnant women was greater than those for FPG, 2hPG, and HbA1c. All differences were significant. The AUCs for the predictive values of FPG, 1hPG, 2hPG, and HbA1c in high-risk pregnant women were 0.63, 0.76, 0.71, and 0.67, respectively. The prevalence of PGDM among pregnant women at high risk of diabetes was 5.6%.

CONCLUSION

First-trimester levels of FPG, 1hPG, 2hPG, and HbA1c in high-risk women are significant predictors of GDM, with 1hPG having the most significant predictive value.

Is HbA1c in the first trimester associated with adverse outcomes among pregnant Asian Indian women without gestational diabetes?

AIMS

The aim of this study is to determine the association of elevated HbA1c in the first trimester (HbA1c-FT) with adverse events among pregnant Asian Indian women without gestational diabetes (GDM).

METHODS

This retrospective cohort study included 1618 pregnant women who delivered at a single urban tertiary care center and had HbA1c-FT estimation between January 2011 and September 2017. Those with GDM according to a 75-g OGTT after 24 gestational weeks were excluded. Multivariable logistic regression models assessed the association between elevated HbA1c-FT and adverse events.

RESULTS

At a cutoff of ≥37 mmol/mol (5.5%), HbA1c-FT was associated with preterm birth at <37 gestational weeks (adjusted odds ratio (OR) 2.10, 95% CI 1.11-3.98). There was a continuum of risk for primary caesarean delivery with higher HbA1c-FT levels (adjusted OR per 5-mmol/mol (0.5%) increase in HbA1c-FT for primary caesarean delivery: 1.27, 95% CI 1.06-1.52). In the crude analysis, gestational hypertension was associated with HbA1c-FT, but not after adjustment for confounding factors. HbA1c-FT was not associated with other adverse events (macrosomia, large for gestational age babies, or other neonatal complications).

CONCLUSIONS

Even without GDM, the results suggest an association of HbA1c-FT with preterm birth and primary caesarian delivery among Asian Indian women.

Global burden of early pregnancy gestational diabetes mellitus (eGDM): A systematic review

AIMS

Gestational diabetes mellitus (GDM) diagnosed during the first trimester of pregnancy is called 'early pregnancy Gestational Diabetes Mellitus' (eGDM). The burden of eGDM has only been studied sporadically. This review aims to understand the global burden of eGDM in terms of prevalence, risk factors, pregnancy outcomes, treatment and postpartum dysglycemia.  METHODS: A review of epidemiologic studies reporting on early GDM screening as per Joanna Briggs Institute (JBI) methodology for prevalence reviews was conducted. A customized search strategy was used to search electronic databases namely, PubMed, CINAHL, EMBASE, Cochrane Library, Scopus, MEDLINE, Ovid, ScienceDirect, and Google Scholar. Three independent reviewers reviewed studies using Covidence software. Observational studies irrespective of study design and regardless of diagnostic criteria were included. Quality of evidence was appraised, and findings were synthesized.

RESULTS

Of 58 included studies, 41 reported a prevalence of eGDM, ranging from 0.7 to 36.8%. Body mass index (BMI), previous history of GDM, family history of diabetes and multiparity were reported as eGDM risk factors. Adverse pregnancy outcomes associated with eGDM were macrosomia, caesarean delivery, induction of labour, hypertension, preterm delivery, and shoulder dystocia. The incidence of postpartum dysglycemia and the need for insulin was higher in women with eGDM. The risk of bias was moderate. Heterogeneity of studies is a limitation. Meta-analysis was not performed.

CONCLUSIONS

There is heterogeneity in the prevalence of eGDM and intrapartum and postpartum ill effects for the mother and the offspring. There is a need to develop a universal screening protocol for eGDM.

The role of first-trimester HbA1c in the early detection of gestational diabetes

Background

We aimed to assess the utility of HbA1c in the early detection of gestational diabetes (GDM) in the first trimester.

Methods

This prospective study was performed on 700 pregnant women in the perinatology clinic at a tertiary university hospital from March 2018 to March 2020. For all pregnant women, HbA1c and fasting blood glucose (FBG) levels were examined during the first trimester. Then, a GDM screening test was done within 24–28 weeks of pregnancy using a 100 g oral glucose tolerance test (OGTT) as the gold standard test. The GDM diagnosis was made according to the American Diabetes Association (ADA) criteria. Sensitivity, specificity, positive (PPV), and negative predictive value (NPV) of HbA1c and FBG were calculated using the receiver operating characteristic (ROC) curve.

Results

Of 700 participants, one hundred and fifteen (16.4%) women had GDM. The GDM patients were significantly older and had a higher pre-gestational body mass index and pregnancy weight gain compared to the non-GDM participants. The sensitivity and specificity for ruling out GDM at an HbA1c cut-off value of 4.85% was 92.2 and 32.8%, respectively, with a 95.5% NPV and a 21.2% PPV. Furthermore, sensitivity and specificity for diagnosing GDM at an HbA1c cut-off value of 5.45% was 54.8 and 96.8%, respectively, with a 91.5% NPV and a 76.8% PPV. Using HbA1c could decline OGTT in 40.4% of the pregnant women (28.7% with HbA1c < 4.85 and 11.7% with HbA1c ≥ 5.45%).

Conclusion

It seems that the first-trimester HbA1c cannot replace OGTT for the diagnosis of GDM because of its insufficient sensitivity and specificity. However, women with higher first-trimester HbA1c had a high risk for GDM incidence.

HbA1c at the time of testing for gestational diabetes identifies women at risk for pregnancy complications

OBJECTIVE

- It is unclear whether glycated haemoglobin (HbA1c) has utility in predicting adverse outcomes in gestational diabetes mellitus (GDM). The aims of the study were to examine the predictive value of HbA1c at GDM diagnosis with adverse pregnancy outcomes.

RESEARCH DESIGN AND METHODS

- This was a cohort study of 4,383 women with GDM between 2011 and 2018. We assessed the association of HbA1c with pregnancy outcomes using logistic regression models before and after adjustment for predefined risk factors of GDM. We examined these associations considering HbA1c as categorical variables using five pre-specified HbA1c classes: and as a continuous variable.

RESULTS

- An HbA1c ≥ 5.6% (38 mmol/mol) identified women with at greater risk for macrosomia: odds ratio (OR) [95% confidence interval] = 2.12 [1.29; 3.46] for HbA1c = 5.6-5.9% and 2.06 [1.14; 3.70] for HbA1c > 5.9% versus HbA1c ≤ 4.5% (26 mmol/mol). Similarly, HbA1c ≥ 5.6% (38 mmol/mol) was associated with greater risk for caesarean: 1.64 [1.06; 2.53] for HbA1c = 5.6-5.9% and 1.58 [0.93; 2.7] for HbA1c > 5.9% (41 mmol/mol) versus HbA1c ≤ 4.5% (26 mmol/mol). Using HbA1c ≤ 4.5% (26 mmol/mol) as reference category, HbA1c > 5.9% (41 mmol/mol) increased the OR of preterm delivery to 3.33 [1.27; 8.71]. HbA1c remained significant for Adverse Pregnancy Outcome Composite after adjustment (P < 0.0001).

DISCUSSION

- Our finding suggests that a single HbA1c reading may be a useful pragmatic tool to identify women at risk. Such identification may be a useful guide for identifying and applying preventative treatment for women at increased risk.

Gestational Diabetes Mellitus in Europe: A Systematic Review and Meta-Analysis of Prevalence Studies

Background

Gestational Diabetes Mellitus (GDM) is defined as the type of hyperglycemia diagnosed for the first-time during pregnancy, presenting with intermediate glucose levels between normal levels for pregnancy and glucose levels diagnostic of diabetes in the non-pregnant state. We aimed to systematically review and meta-analyze studies of prevalence of GDM in European countries at regional and sub-regional levels, according to age, trimester, body weight, and GDM diagnostic criteria.

Methods

Systematic search was conducted in five databases to retrieve studies from 2014 to 2019 reporting the prevalence of GDM in Europe. Two authors have independently screened titles and abstracts and full text according to eligibility using Covidence software. A random-effects model was used to quantify weighted GDM prevalence estimates. The National Heart, Lung, and Blood Institute criteria was used to assess the risk of bias.

Results

From the searched databases, 133 research reports were deemed eligible and included in the meta-analysis. The research reports yielded 254 GDM-prevalence studies that tested 15,572,847 pregnant women between 2014 and 2019. The 133 research reports were from 24 countries in Northern Europe (44.4%), Southern Europe (27.1%), Western Europe (24.1%), and Eastern Europe (4.5%). The overall weighted GDM prevalence in the 24 European countries was estimated at 10.9% (95% CI: 10.0-11.8, I2 : 100%). The weighted GDM prevalence was highest in the Eastern Europe (31.5%, 95% CI: 19.8-44.6, I2 : 98.9%), followed by in Southern Europe (12.3%, 95% CI: 10.9-13.9, I2 : 99.6%), Western Europe (10.7%, 95% CI: 9.5-12.0, I2 : 99.9%), and Northern Europe (8.9%, 95% CI: 7.9-10.0, I2 : 100). GDM prevalence was 2.14-fold increased in pregnant women with maternal age ≥30 years (versus 15-29 years old), 1.47-fold if the diagnosis was made in the third trimester (versus second trimester), and 6.79- fold in obese and 2.29-fold in overweight women (versus normal weight).

Conclusions

In Europe, GDM is significant in pregnant women, around 11%, with the highest prevalence in pregnant women of Eastern European countries (31.5%). Findings have implications to guide vigilant public health awareness campaigns about the risk factors associated with developing GDM.

Systematic Review Registration

PROSPERO [https://www.crd.york.ac.uk/PROSPERO/], identifier CRD42020161857.

Early Gestational Diabetes Mellitus: Diagnostic Strategies and Clinical Implications

Preexisting diabetes mellitus (DM) should be ruled out early in pregnancy in those at risk. During screening, a significant proportion of women do not reach the threshold for overt DM but fulfill the criteria used for diagnosing conventional gestational DM (cGDM). There is no consensus on the management of pregnancies with intermediate levels of hyperglycemia thus diagnosed. We have used the term early gestational DM (eGDM) for this condition and reviewed the currently available literature. Fasting plasma glucose (FPG), oral glucose tolerance test, and glycated hemoglobin (HbA1c) are the commonly employed screening tools in early pregnancy. Observational studies suggest that early pregnancy FPG and Hba1c correlate with the risk of cGDM and adverse perinatal outcomes. However, specific cut-offs, including those proposed by the International Association of the Diabetes and Pregnancy Study Group, do not reliably predict the development of cGDM. Emerging data, though indicate that FPG ≥ 92 mg/dL (5.1 mmol/L), even in the absence of cGDM, signals the risk for perinatal complication. Elevated HbA1c, especially a level ≥ 5.9%, also correlates with the risk of cGDM and worsened outcome. HbA1c as a diagnostic test is however besieged with the usual caveats that occur in pregnancy. The studies that explored the effects of intervention present conflicting results, including a possibility of fetal malnutrition and small-for-date baby in the early treatment group. Diagnostic thresholds and glycemic targets in eGDM may differ, and large multicenter randomized controlled trials are necessary to define the appropriate strategy.

Association of higher HbA1c within the normal range with adverse pregnancy outcomes: a cross-sectional study

OBJECTIVE

The aim of this study was to investigate the association between a relatively high HbA1c level within the normal range and the risk of adverse pregnancy outcomes.

METHODS

This retrospective cohort study was conducted between March 2018 and March 2019 at Women's Hospital, School of Medicine, Zhejiang University. Multiple logistic regression models after adjusting for plausible confounders were implemented to assess the relationships between the level of HbA1c and adverse pregnancy outcomes.

RESULTS

A total of 8585 women were included in our study. The rates of preterm birth, macrosomia and preeclampsia were 4.4% (380/8585), 5.3% (457/8585) and 1.7% (149/8585), respectively. After adjusting for potential confounding variables, an HbA1c range of 5.5-5.9% (37-41 mmol/mol) remained significantly associated with an increased risk of preterm delivery (a-OR 2.27; 95% CI, 1.50-3.43), macrosomia (a-OR 1.97; 95% CI, 1.32-2.94) and preeclampsia (a-OR 3.70; 95% CI, 2.07-6.60). GDM-negative pregnant women with an HbA1c level in the range of 5.5-5.9% (37-41 mmol/mol) had an increased risk of preterm delivery (a-OR 2.84; 95% CI, 1.71-4.71) and preeclampsia (a-OR 3.82; 95% CI, 1.81-8.04). However, GDM-positive pregnant women had an increased risk of macrosomia (a-OR 2.12; 95% CI, 1.13-3.97) and preeclampsia (a-OR 2.62; 95% CI, 1.01-6.81).

CONCLUSION

A higher HbA1c level within the normal range is an independent risk factor for preterm delivery and preeclampsia, especially among GDM-negative women. Therefore, relevant medical staff should enhance the awareness of risk and prevention to strengthen pregnancy monitoring.

Diagnosis and Management of Gestational Diabetes Mellitus: An Overview of National and International Guidelines

Importance

Gestational diabetes mellitus (GDM) represents one of the most frequent complications of pregnancy and is associated with increased maternal and neonatal morbidity. Its incidence is rising, mostly due to an increase in maternal age and maternal obesity rate.

Objective

The aim of this study was to review and compare the recommendations of the most recently published guidelines on the diagnosis and management of this condition.

Evidence Acquisition

A descriptive review of guidelines from the National Institute for Health and Care Excellence (NICE), the International Federation of Gynecology and Obstetrics, the Australasian Diabetes in Pregnancy Society (ADIPS), the Society of Obstetricians and Gynecologists of Canada (SOGC), the American College of Obstetricians and Gynecologists (ACOG), the American Diabetes Association, and the Endocrine Society on gestational diabetes mellitus was carried out.

Results

The NICE guideline recommends targeted screening only for women with risk factors, whereas the International Federation of Gynecology and Obstetrics, ADIPS, SOGC, and the ACOG recommend screening for all pregnant women at 24 to 28 weeks of gestation in order to diagnose and effectively manage GDM; they also state that women with additional risk factors should be screened earlier (ie, in the first trimester) and retested at 24 to 28 weeks, if the initial test is negative. These guidelines describe similar risk factors for GDM and suggest the same thresholds for the diagnosis of GDM when using a 75-g 2-hour oral glucose tolerance test. Of note, the NICE only assesses the fasting and the 2-hour postprandial glucose levels for the diagnosis of GDM. Moreover, the SOGC and the ACOG do not recommend this test as the optimal screening method. The Endocrine Society alone, on the other hand, recommends the universal testing of all pregnant women for diabetes before 13 weeks of gestation or as soon as they attend the antenatal service and retesting at 24 to 28 weeks if the initial results are normal. In addition, there is a general consensus on the appropriate ultrasound surveillance of pregnancies complicated with GDM, and all the medical societies, except the ADIPS, recommend self-monitoring of capillary glucose to assess the glycemic control and set the same targets for fasting and postprandial glucose levels. There is also agreement that lifestyle modifications should be the first-line treatment; however, the reviewed guidelines disagree on the medical management of GDM. In addition, there are controversies regarding the timing of delivery, the utility of hemoglobin A_1c measurement, and the postpartum and lifelong screening for persistent hyperglycemia and type 2 diabetes. However, all the guidelines state that all women in pregnancies complicated by GDM should undergo a glycemic test at around 6 to 12 weeks after delivery. Finally, there is a universal consensus on the importance of breastfeeding and preconception screening before future pregnancies.

Conclusions

As GDM is an increasingly common complication of pregnancy, it is of paramount importance that inconsistencies between national and international guidelines should encourage research to resolve the issues of controversy and allow uniform international protocols for the diagnosis and management of GDM, in order to safely guide clinical practice and subsequently improve perinatal and maternal outcomes.

Prediabetes and pregnancy: Early pregnancy HbA1c identifies Australian Aboriginal women with high-risk of gestational diabetes mellitus and adverse perinatal outcomes

AIMS

To assess whether early pregnancy HbA1c can predict gestational diabetes mellitus (GDM) and adverse birth outcomes in Australian women.

METHODS

Prospective study of 466 women without diabetes, aged ≥16-years at first antenatal presentation. Recruitment was from 27 primary healthcare sites in rural and remote Australia from 9-January 2015 to 31-May 2018. HbA1c was measured with first antenatal investigations (<20-weeks gestation). Primary outcome measure was predictive value of HbA1c for GDM, by routine 75 g oral glucose tolerance test (OGTT; ≥24-weeks gestation), and for large-for-gestational-age (LGA) newborn.

RESULTS

Of 396 (129 Aboriginal) women with routine OGTT, 28.8% had GDM (24.0% Aboriginal). HbA1c ≥5.6% (≥38 mmol/mol) was highly predictive (71.4%, 95% CI; 47.8-88.7%) for GDM in Aboriginal women, and in the total cohort increased risk for LGA newborn (RR 2.04, 95% CI; 1.03-4.01, P = 0.040). There were clear differences between Aboriginal and non-Aboriginal women: 16.3% v 5.2% (P < 0.001) had elevated HbA1c whereas 12.4% v 29.6% (P < 0.001) developed hyperglycemia during pregnancy.

CONCLUSIONS

Early pregnancy HbA1c ≥5.6% (≥38 mmol/mol) identifies Aboriginal women with apparent prediabetes and elevated risk of having an LGA newborn. Universal HbA1c at first antenatal presentation could facilitate earlier management of hyperglycemia and improved perinatal outcome in this high-risk population.

Universal HbA1c screening and gestational diabetes: a comparison with clinical risk factors

BACKGROUND

Screening strategies for gestational diabetes mellitus (GDM), particularly early GDM, have traditionally relied upon the use of clinical risk factors (CRFs). Although commonly used in nonpregnant patients, HbA1c screening is not widely used despite reports of abnormal HbA1c values being predictive of GDM development. The aims of this study are to assess the utility of universal HbA1c screening in predicting GDM and to compare universal screening to targeted CRF-based screening for the diagnosis of GDM.

STUDY DESIGN

This is a retrospective cohort study of patients undergoing universal HbA1c screening at ≤16 completed weeks gestation with a singleton pregnancy between December 2016 and April 2018 at a single urban tertiary care center. Patients with preexisting diabetes (HbA1c ≥6.5%) or patients who did not have glucose tolerance testing were excluded. Patients with HbA1c 5.7-6.4% underwent early two-step GDM screening. Positive screens were diagnosed with early GDM. Normal early screeners underwent repeat 3rd trimester screening. Clinical risk factors for early GDM screening at our institution prior to universal screening were history of GDM, body mass index (BMI) ≥40 kg/m², prior macrosomia (birth weight ≥4000 g) or stillbirth, and polycystic ovary syndrome. Multivariable regression was performed to assess the relationship between HbA1c and GDM. The predictive ability of universal HbA1c screening compared to that of CRFs was evaluated by testing for differences in the area under the curve (AUC) of receiver operating curves (ROCs).

RESULTS

One thousand nine hundred and fifteen patients met inclusion criteria. Two hundred and thirty-one (12.1%) patients had an elevated HbA1c ≥5.7%. Patients with elevated HbA1c were more likely to be older, Black, or obese compared with patients with normal HbA1c values. After adjusting for Black race, BMI, age, and public insurance, the odds of GDM development are 3.50 (95%CI 2.26-5.39) times higher among patients with HbA1c ≥5.7% compared to those with a normal HbA1c. Clinical risk factors for early glucose screening were present in 33% of patients with an elevated HbA1c. The AUC of CRF screening and HbA1c ≥5.7% was 0.72 and 0.75, respectively (p= .07), after controlling for Black race, BMI, maternal age, and insurance.

CONCLUSIONS

An elevated HbA1c is associated with an increased risk of GDM. Universal HbA1c screening performs as favorably as CRF based screening for the prediction of GDM.

A Review on Research Progress in the Application of Glycosylated Hemoglobin and Glycated Albumin in the Screening and Monitoring of Gestational Diabetes

Glycosylated hemoglobin (HbA1C) and glycated albumin (GA) can be used for blood glucose management of a person with diabetes as a result of their convenience and stability. However, there is no corresponding standard for the application of glycosylated hemoglobin and glycosylated albumin in gestational diabetes mellitus (GDM). In this review, we summarize the published research and discuss three aspects of the significance of HBA1C and GA in GDM patients: screening of gestational diabetes mellitus, blood glucose monitoring and the relationship with pregnancy outcome. At present, studies suggest that HBA1C can be used as a screening indicator for pregnant women, but it cannot completely replace OGTT. HbA1C and GA can be used for blood glucose management in patients with GDM to reduce the incidence of GDM complications. However, the application of HBA1C and GA in GDM still needs more research and clinical practice support.

Screening for Gestational Diabetes Mellitus in Early Pregnancy: What Is the Evidence?

The incidence of gestational diabetes mellitus (GDM) is increasing worldwide. This has a significant effect on the health of the mother and offspring. There is no doubt that screening for GDM between 24 and 28 weeks is important to reduce the risk of adverse pregnancy outcomes. However, there is no consensus about diagnosis and treatment of GDM in early pregnancy. In this narrative review on the current evidence on screening for GDM in early pregnancy, we included 37 cohort studies and eight randomized controlled trials (RCTs). Observational studies have shown that a high proportion (15–70%) of women with GDM can be detected early in pregnancy depending on the setting, criteria used and screening strategy. Data from observational studies on the potential benefit of screening and treatment of GDM in early pregnancy show conflicting results. In addition, there is substantial heterogeneity in age and BMI across the different study populations. Smaller RCTs could not show benefit but several large RCTs are ongoing. RCTs are also necessary to determine the appropriate cut-off for HbA1c in pregnancy as there is limited evidence showing that an HbA1c ≥6.5% has a low sensitivity to detect overt diabetes in early pregnancy.

Prediction Method of Gestational Diabetes Based on Electronic Medical Record Data

At present, the secondary application of electronic medical records is focused on auxiliary medical diagnosis to improve the accuracy of clinical diagnosis. The main research in this article is the prediction method of gestational diabetes based on electronic medical record data. In the original data, the ID number of the medical examiner did not match the medical examination record. In order to ensure the accuracy of the data, this part of the record was removed. First, the preparation stage before building the model is to determine the baseline accuracy of the original data, test the effectiveness of the machine learning algorithm, and then balance the target data set to solve the bias caused by the imbalance between data classes and the illusion of excessive model prediction results. Then, the disease prediction model is constructed by dividing the data set, selecting parameters and algorithms, and visualizing the model. Finally, the effect of predictive model construction is comprehensively judged based on multiple evaluation indicators and control experimental models. In this paper, the RF model can be used to rank the importance of the feature importance of the output feature on the importance of the classification result of the input feature. In order to test the accuracy of regression prediction, the experiment uses absolute mean error and root mean square error to evaluate the accuracy of fasting blood glucose prediction. A logistic regression model is constructed through the training set, and the test set data are brought into the prediction model for prediction. Experimental data show that when the features filtered by WBFS are used, the accuracy, F1 value, and AUC value of logistic regression are 0.809, 0.881, and 0.825, respectively, which is an increase of about 12% compared with when the feature is not used. The results show that the electronic medical record data drive can effectively improve the accuracy of predicting gestational diabetes.

Predictive Value of First-Trimester Glycosylated Hemoglobin Levels in Gestational Diabetes Mellitus: A Chinese Population Cohort Study

This study was aimed at exploring the predictive value of first-trimester glycosylated hemoglobin (HbA1c) levels in the diagnosis of gestational diabetes mellitus (GDM). A total of 744 pregnant women registered at the Peking University International Hospital between March 2017 and March 2019 were included in this study. Data on personal characteristics and biochemical indicators of the pregnant women were collected during the first trimester. The International Association of Diabetes and Pregnancy Study Groups has adopted specific diagnostic criteria as the gold standard for the diagnosis of GDM. Receiver operating characteristic (ROC) curve statistics were used to assess the predictive value of first-trimester HbA1c levels in the diagnosis of GDM. HbA1c levels in the first trimester were significantly higher in the GDM group than in the non-GDM group (5.23% ± 0.29% vs. 5.06 ± 0.28%, P < 0.05). The first-trimester HbA1c level was an independent risk factor for gestational diabetes. The area under the ROC curve (AUC) of HbA1c for GDM was 0.655 (95% confidence interval 0.620-0.689, P < 0.001). The positive likelihood ratio was the highest at HbA1c = 5.9%, sensitivity was 2.78, and specificity was 99.83%. There was no statistical difference in AUC between fasting blood glucose and HbA1c (P = 0.407). First-trimester HbA1c levels can be used to predict GDM. The risk of GDM was significantly increased in pregnant women with first-trimester HbA1c levels > 5.9%. There was no statistical difference between first-trimester HbA1c and fasting blood glucose levels in predicting GDM.

Early Predictors of Gestational Diabetes Mellitus in IVF-Conceived Pregnancies

OBJECTIVE

Gestational diabetes mellitus (GDM) is associated with adverse maternal and fetal outcomes. This study aimed to identify early and reliable GDM predictors that would enable implementation of preventive and management measures.

METHODS

The participants were a 28-week prospective cohort of in vitro fertilization (IVF)-conceived pregnant women (≤39 years, body mass index [BMI] 18.5-38 kg/m²) without a known history of diabetes mellitus. Fasting blood samples were analyzed at baseline (pre-IVF) and 12 weeks' gestation for reproductive hormones, glucose, serum insulin, lipids, thyroid function, adiponectin, and lipopolysaccharide-binding protein. At 28 weeks, a 75-g oral glucose tolerance test was used to screen for GDM.

RESULTS

For the overall group at baseline, 22% had BMI ≥30 kg/m², 45% had polycystic ovary syndrome, 16% had hemoglobin A1C of 5.7% to 6.1%, and 14% had a past history of GDM. At 28 weeks of gestation (n = 158), 34 women had developed GDM and 124 had not. Significant baseline predictors of GDM onset included greater BMI (29.0 vs 25.8 kg/m²), older age (34 vs 32 years), higher levels of follicle-stimulating hormone/luteinizing hormone ratio (1.2 vs 1.0), hemoglobin A1C (5.5 vs 5.2%), insulin (10.6 vs 7.1 μIU/mL), homeostatic model assessment of insulin resistance (2.2 vs 1.7), total cholesterol (199 vs 171 mg/dL), and low-density lipoprotein cholesterol (123 vs 105 mg/dL), and lower triglyceride levels (74 vs 76 mg/dL). Significant 12-week GDM predictors included greater maternal weight gain (delta: 3.4 vs 1.5 kg) and higher levels of insulin (11.3 vs 7.6 μIU/mL), triglycerides (178 vs 120 mg/dL), and homeostatic model assessment of insulin resistance (2.3 vs 1.5). Twelve-week BMI is a predictor of GDM following adjustment for polycystic ovary syndrome status and maternal age.

CONCLUSION

While preconception maternal BMI, age, and follicle-stimulating hormone/luteinizing hormone ratio are predictors of subsequent development of GDM, early IVF-conceived gestational weight gain is the best predictor of GDM onset.

Effects of in vitro fertilization (IVF) therapies on metabolic, endocrine and inflammatory status in IVF-conceived pregnancy

RATIONALE

In vitro fertilization (IVF) is a common treatment for infertility. In mice, IVF is associated with development of glucose intolerance. However, human data are limited regarding the metabolic, endocrine and inflammatory effects of IVF therapy in IVF-conceived pregnancies.

OBJECTIVE

To explore effects of IVF therapies on metabolic, endocrine and inflammatory parameters in IVF-conceived pregnancy.

METHODOLOGY

Twelve-week prospective observational study of adult normoglycaemic women, BMI 18.5-38 kg/m² and ≤ 39 years awaiting IVF therapy. Fasting blood samples were collected at baseline and 12 weeks, and serum analysed for reproductive hormones, glucose, lipids, insulin sensitivity, thyroid status, adiponectin inflammatory marker and lipopolysaccharide-binding protein (LBP).

RESULTS

Two hundred and seventy-five women were analysed: 158 IVF-conceived pregnant women and 117 with failed IVF. Compared with baseline, nonpregnant women had significant (P < .001) increases in 12-week glucose (86.04-87.62 mg/dL), insulin (8.72-9.37 µIU/mL), HOMA-IR (1.9-2.1), T-Chol (169.5-174.9 mg/dL), TG (71.0-83.7 mg/dL) and HDL-C (52.0-54.11 mg/dL) levels. At 12 weeks, pregnant women also had (P < .001) increases in T-Chol (177.5-199.5 mg/dL), TG (73.5-126.78 mg/dL) and HDL-C (55.3-65.1 mg/dL), while a significant reduction in glucose (86.15-82.19 mg/dL), HbA1c (5.3-5.08%) and TSH (1.71-1.36 µIU/mL) levels from baseline. Adiponectin and LBP levels remained the same in either group.

CONCLUSION

In vitro fertilization hormonal therapy impairs glucose and insulin levels; these effects are masked in early pregnancy. Changes in lipid profile occur following IVF therapies regardless of pregnancy outcome. Neither adiponectin nor LBP is affected by IVF therapies and during early IVF-conceived pregnancy.

No association between early maternal HbA1c and offspring birthweight among women without pre-existing diabetes in Greenland

Studies of the association between maternal blood glucose measured by glycated haemoglobin (HbA1c) during pregnancy and the offspring’s birthweight have been heterogeneous. The aim of this study was to examine the association between maternal HbA1c level before gestational week 20 and the offspring’s birthweight among predominantly indigenous women in Greenland. A retrospective cohort study including all women (n = 503) and their offspring delivered from September 2015 to September 2016 at Queen Ingrid’s Hospital in Nuuk was conducted. Data were obtained from the electronic medical record. Linear regression models were used to analyse the effect of maternal HbA1c on the offspring’s birthweight with adjustment and stratification for relevant confounders and effect modifiers. Birthweight increased with 3.3 g per mmol/mol increase in HbA1c. Yet, no significant association between maternal HbA1c and the offspring’s birthweight was found after adjustment for maternal age, ethnicity, residence, smoking, and parity (β = 0.058, p = 0.711). Among obese women, a borderline significant positive association (β = 0.657, p = 0.059) was found. For term newborns, this corresponded to an increase in birthweight of 31 g per mmol/mol increase in HbA1c. Based on the current study, the use of HbA1c during pregnancy to detect the risk of delivering a newborn with macrosomia is not recommended in Greenland.

Abbreviation: HbA1c: glycosylated haemoglobin; GA: gestational age; SD: standard deviation; CI: confidence interval.

HbA1c during early pregnancy reflects beta-cell dysfunction in women developing GDM

INTRODUCTION

It is of current interest to assess eligibility of hemoglobin A1c (HbA1c) as a screening tool for earlier identification of women with risk for more severe hyperglycemia in pregnancy but data regarding accuracy are controversial. We aimed to evaluate if HbA1c mirrors pathophysiological precursors of glucose intolerance in early pregnancy that characterize women who develop gestational diabetes mellitus (GDM).

RESEARCH DESIGN AND METHODS

220 pregnant women underwent an HbA1c measurement as well as an oral glucose tolerance test (OGTT) with multiple measurements of glucose, insulin and C-peptide for evaluation of insulin sensitivity and beta-cell function at 16th gestational week (IQR: 14-18). Clinical follow-ups were performed until end of pregnancy.

RESULTS

Increased maternal HbA1c ≥5.7% (39 mmol/mol) corresponding to pre-diabetes outside of pregnancy was associated with altered glucose dynamics during the OGTT. Pregnancies with early HbA1c ≥5.7% showed higher fasting (90.4±13.2 vs 79.7±7.2 mg/dL, p<0.001), mean (145.6±31.4 vs 116.2±21.4 mg/dL, p<0.001) as well as maximum glucose concentrations and tended to a delay in reaching the maximum glucose level compared with those with normal-range HbA1c (186.5±42.6 vs 147.8±30.1 mg/dL, p<0.001). Women with increased HbA1c showed impaired beta-cell function and differences in disposition index independent of body mass index status. We observed a high specificity for the HbA1c cut-off of 5.7% for GDM manifestation (0.96, 95% CI 0.91 to 0.98) or need of glucose-lowering medication (0.95, 95% CI 0.90 to 0.98) although overall predictive accuracy was moderate to fair. Further, elevated HbA1c was associated with higher risk for delivering large-for-gestational-age infants, also after adjustment for GDM status (OR 4.4, 95% CI 1.2 to 15.0, p=0.018).

CONCLUSIONS

HbA1c measured before recommended routine screening period reflects early pathophysiological derangements in beta-cell function and glucose disposal that are characteristic of GDM development and may be useful in early risk stratification.

Performance of early pregnancy HbA1c for predicting gestational diabetes mellitus and adverse pregnancy outcomes in obese European women

AIMS

To investigate the performance of early pregnancy HbA_1c for predicting gestational diabetes mellitus (GDM) and adverse pregnancy outcomes in obese women.

METHODS

Post hoc analysis using data from the Vitamin D And Lifestyle Intervention for GDM prevention trials conducted across 9 European countries (2012-2014). Pregnant women (BMI ≥ 29 kg/m²) underwent a baseline HbA_1c and oral glucose tolerance tests at < 20 weeks, 24-28 weeks, and 35-37 weeks. Women with GDM were referred for treatment.

RESULTS

Among the 869 women tested, the prevalence of GDM was 25.9% before 20 weeks, with a further 8.6% at 24-28 weeks. The areas under the curves for HbA_1c at the two time points were 0.55 (0.50-0.59) and 0.54 (0.47-0.61), respectively. An early HbA_1c ≥ 5.7% (39 mmol/mol) (N = 111) showed low sensitivity (18.2%) with 89.1% specificity for GDM before 20 weeks, at 24-28 weeks (sensitivity of 8.0% and specificity of 88.6% after excluding early GDM), and throughout gestation (sensitivity of 15.9% and specificity of 89.4%). The ≥ 5.7% (39 mmol/mol) threshold was significantly associated with concurrent GDM before 20 weeks (adjusted OR (aOR) 2.77(1.39-5.51)) and throughout gestation (aOR 1.72 (1.02-2.89)), but not adverse pregnancy outcomes.

CONCLUSIONS

Early pregnancy HbA_1c is of limited use for predicting either GDM or adverse outcomes in overweight/obese European women.

The accuracy of haemoglobin A1c as a screening and diagnostic test for gestational diabetes: a systematic review and meta-analysis of test accuracy studies

PURPOSE OF REVIEW

Gestational diabetes mellitus (GDM) is associated with adverse pregnancy complications. Accurate screening and diagnosis of gestational diabetes are critical to treatment, and in a pandemic scenario like coronavirus disease 2019 needing a simple test that minimises prolonged hospital stay. We undertook a meta-analysis on the screening and diagnostic accuracy of the haemoglobin A1c (HbA1c) test in women with and without risk factors for gestational diabetes.

RECENT FINDINGS

Unlike the oral glucose tolerance test, the HbA1c test is simple, quick and more acceptable. There is a growing body of evidence on the accuracy of HbA1c as a screening and diagnostic test for GDM. We searched Medline, Embase and Cochrane Library and selected relevant studies. Accuracy data for different thresholds within the final 23 included studies (16 921 women) were pooled using a multiple thresholds model. Summary accuracy indices were estimated by selecting an optimal threshold that optimises either sensitivity or specificity according to different scenarios.

SUMMARY

HbA1c is more useful as a specific test at a cut-off of 5.7% (39 mmol/mol) with a false positive rate of 10%, but should be supplemented by a more sensitive test to detect women with GDM.

Glycated haemoglobin in the first trimester: A predictor of gestational diabetes mellitus in pregnant Asian Indian women

AIM

To assess the efficacy of first trimester glycated hemoglobin (HbA1c-FT) in diagnosing or predicting gestational diabetes mellitus (GDM) in Asian Indian women.

METHODS

This retrospective cohort study involved 2275 women who underwent both HbA1c-FT estimation and GDM screening with a one-step 75 g oral glucose tolerance test. Receiver Operating Characteristic (ROC) curve statistics were applied to assess the discriminative ability of HbA1c-FT in GDM diagnosis. A multivariable logistic regression analysis after adjusting for plausible confounders was used to evaluate the independent effect of HbA1c-FT on GDM diagnosis.

RESULTS

The mean HbA1c-FT of GDM (n = 578) and non-GDM women (n = 1697) were 5.04 + 0.04% and 4.9 + 0.37%, respectively (p < 0.001). Compared to women with a HbA1c-FT < 5.2%, the adjusted odds ratio to develop GDM of women with an HbA1c-FT range of 5.2-5.5% and those >5.6% to develop GDM were 1.627 (p < 0.004) and 2.6 (p < 0.001), respectively. The area under the ROC curve to detect GDM was 0.606 (95% CI: 0.519-0.633 p < 0.001), but the sensitivity and specificity of the HbA1c-FT were not sufficient to diagnose, rule in or rule out GDM.

CONCLUSIONS

HbA1c-FT is an independent GDM predictor in Asian Indian women but lacks sufficient sensitivity or specificity for use as a diagnostic test.

Early Assessment of the Risk for Gestational Diabetes Mellitus: Can Fasting Parameters of Glucose Metabolism Contribute to Risk Prediction?

BACKGROUND

An early identification of the risk groups might be beneficial in reducing morbidities in patients with gestational diabetes mellitus (GDM). Therefore, this study aimed to assess the biochemical predictors of glycemic conditions, in addition to fasting indices of glucose disposal, to predict the development of GDM in later stage and the need of glucose-lowering medication.

METHODS

A total of 574 pregnant females (103 with GDM and 471 with normal glucose tolerance [NGT]) were included. A metabolic characterization was performed before 15⁺⁶ weeks of gestation by assessing fasting plasma glucose (FPG), fasting insulin (FI), fasting C-peptide (FCP), and glycosylated hemoglobin (HbA1c). Thereafter, the patients were followed-up until the delivery.

RESULTS

Females with NGT had lower levels of FPG, FI, FCP, or HbA1c at the early stage of pregnancy, and therefore, showed an improved insulin action as compared to that in females who developed GDM. Higher fasting levels of FPG and FCP were associated with a higher risk of developing GDM. Moreover, the predictive accuracy of this metabolic profiling was also good to distinguish the patients who required glucose-lowering medications. Indices of glucose disposal based on C-peptide improved the predictive accuracy compared to that based on insulin. A modified quantitative insulin sensitivity check index (QUICKIc) showed the best differentiation in terms of predicting GDM (area under the receiver operating characteristics curve [ROC-AUC], 72.1%) or need for pharmacotherapy (ROC-AUC, 83.7%).

CONCLUSION

Fasting measurements of glucose and C-peptide as well as the surrogate indices of glycemic condition could be used for stratifying pregnant females with higher risk of GDM at the beginning of pregnancy.

Maternal serum glycosylated hemoglobin and fasting plasma glucose predicts gestational diabetes at the first trimester in Turkish women with a low-risk pregnancy and its relationship with fetal birth weight; a retrospective cohort study

OBJECTIVE

To examine the accuracy of maternal serum glycosylated hemoglobin (HbA1c) and fasting plasma glucose (FPG) levels in predicting gestational diabetes at the first trimester in Turkish women with a low-risk pregnancy and its relationship with fetal birth weight.

METHODS

This cohort study was conducted retrospectively in a tertiary referral hospital from January 2010 to January 2017. HbA1c and FPG serum concentrations were measured in 670 pregnant women at the first-trimester screening. HbA1c and FPG concentrations of women who subsequently developed gestational diabetes mellitus (GDM) were compared to those who did not, and its relationship with fetal weight was investigated.

RESULTS

First-trimester screening was performed on 608 pregnant women, of whom 69 (11.3%) women had developed GDM. Median HbA1c and FPG concentrations were significantly higher in women developing GDM (n = 69) in comparison to those with uncomplicated pregnancies (n = 539) (5.31 ± 0.58% versus 5.01 ± 0.45%, p < .001 and 89.74 ± 8.71% versus 84.09 ± 9.16%, p < .001, respectively). The cut-off value calculated with the highest Youden index was HbA1c levels above 5.6% with a sensitivity of 34.78%, specificity of 89.8%, with a diagnostic accuracy of 83.55%, and FPG levels above 86.85 mg/dl with a sensitivity of 69.57%, specificity of 61.78%, with a diagnostic accuracy of 62.66%. The calculated odds ratio (OR) for HbA1c > 5.6% and FPG > 86 mg/dl were 4.69 (95% CI: 2.66-8.29), and 3.7 (95% CI: 2.15-6.35), respectively. HbA1c and FPG combined had improved the predictive capability for GDM (OR: 7.26, 95% CI: 3.71-14.19). According to correlation analyses, a noteworthy positive correlation was found between HbA1c and, FPG, 50 g GCT, age, BMI, parity, and birth weight. However, there was no correlation between FPG and birth weight.

CONCLUSION

Diagnostic accuracy of HbA1c for GDM prediction in Turkish women with a low-risk pregnancy is 83.55% with a very good negative predictive value of 91.49%. HbA1c and FPG combined enhanced the predictive capability for GDM. In addition, there is a positive relationship between HbA1c and 50 g GCT, and birth weight. However, to suggest HbA1c as a potential screening test for gestational diabetes mellitus, further research is warranted.

Universal early pregnancy glycosylated hemoglobin A1c as an adjunct to Carpenter-Coustan screening: an observational cohort study

BACKGROUND

Early pregnancy screening for preexisting and gestational diabetes mellitus is widely recommended, but the details of screening (eg, targeted vs universal screening, criteria to identify women requiring early screening, specific screening strategy) remain controversial and poorly defined.

OBJECTIVE

The objective of the study was to determine the utility of universal early glycosylated hemoglobin A1c obtained at the first prenatal visit in diagnosing preexisting diabetes and high-risk gestational diabetes mellitus (early glycosylated hemoglobin A1c, 5.9-6.4%). We further sought to determine whether early glycosylated hemoglobin A1c could replace routine Carpenter-Coustan testing and to determine the correlation between early glycosylated hemoglobin A1c and maternal and neonatal morbidity and mortality.

STUDY DESIGN

This was an observational cohort study of women delivering from May 2016 to July 2017 (14 months) at a single county teaching hospital. Multiple gestations and second deliveries during the study interval were excluded. Women with an early glycosylated hemoglobin A1c of ≥ 6.5% were diagnosed with preexisting diabetes. Women with early glycosylated hemoglobin A1c of 5.9-6.4% underwent immediate 3 hour glucose tolerance testing, which if abnormal diagnosed gestational diabetes mellitus and if normal was repeated at 24-28 weeks. Women with early glycosylated hemoglobin A1c <5.9% underwent routine Carpenter-Coustan screening at 24-28 weeks. Receiver-operator curve methodology was used to evaluate the diagnostic properties of early glycosylated hemoglobin A1c for gestational diabetes mellitus. The correlation between early glycosylated hemoglobin A1c and composite measures of maternal and neonatal morbidity and mortality were calculated.

RESULTS

A total of 4144 deliveries remained after exclusions. Median gestational age at early glycosylated hemoglobin A1c draw was 9 weeks (interquartile range, 7-12). Early glycosylated hemoglobin A1c diagnosed 26 women with preexisting diabetes (0.8% of all patients, 37.7% of all preexisting diabetes). A total of 41.9% of 93 women with early glycosylated hemoglobin A1c of 5.9-6.4% had an early diagnosis of gestational diabetes mellitus, accounting for 25.8% of total gestational diabetes mellitus cases. Based on receiver-operator curve analysis, no early glycosylated hemoglobin A1c cutoff had sufficient sensitivity and positive predictive value to diagnose gestational diabetes mellitus. An early glycosylated hemoglobin A1c ≤5.0% (29.2% of patients) had a 98% negative predictive value for gestational diabetes mellitus, suggesting women with an early glycosylated hemoglobin A1c ≤5.0% in a similar-risk population could potentially forego further testing. The per-patient incremental cost for the glycosylated hemoglobin A1c was $3.72.

CONCLUSION

Early glycosylated hemoglobin A1c correlates with maternal and neonatal morbidity and mortality but cannot entirely replace routine Carpenter-Coustan testing because of poor sensitivity. Rather, its use as an adjunct to Carpenter-Coustan testing, with reflex to early 3 hour glucose tolerance testing for those with values 5.9-6.4%, is an inexpensive and simple method that identifies women with preexisting diabetes and high-risk gestational diabetes mellitus early in pregnancy, allowing early intervention and the prospect of improved outcomes.

Optimal first trimester HbA1c threshold to identify Singaporean women at risk of gestational diabetes mellitus and adverse pregnancy outcomes: A pilot study

This pilot study examined the use of early HbA1c in screening for gestational diabetes mellitus and adverse pregnancy outcomes in Singapore. One hundred and fifty-one pregnant women with a gestational age of under 14 weeks had an HbA1c test measured with their antenatal bloods prior to a second trimester oral glucose tolerance test. Patient characteristics and pregnancy outcome data were collected. Gestational diabetes mellitus prevalence was 11%. A receiver operating characteristic curve showed an HbA1c level of 5.2% (33 mmol/mol), had an 82% sensitivity, 72% specificity, 97% negative predictive value and 27% positive predictive value to predict gestational diabetes mellitus. Women with HbA1c of 5.2% (33 mmol/mol) or over 5.2% (33 mmol/mol) were older, had higher BMI and were less likely to be Chinese than those with HbA1c less than 5.2% (33 mmol/mol). There was no difference in pregnancy outcomes. Early HbA1c less than 5.2% (33 mmol/mol) may be useful to exclude low-risk Singaporean women from further testing, while those with HbA1c of 5.2% (33 mmol/mol) or greater would still need a oral glucose tolerance test between 24 and 28 weeks' gestation.

ACOG Practice Bulletin No. 190: Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is one of the most common medical complications of pregnancy. However, debate continues to surround the diagnosis and treatment of GDM despite several recent large-scale studies addressing these issues. The purposes of this document are the following: 1) provide a brief overview of the understanding of GDM, 2) review management guidelines that have been validated by appropriately conducted clinical research, and 3) identify gaps in current knowledge toward which future research can be directed.

HbA1c Measured in the First Trimester of Pregnancy and the Association with Gestational Diabetes

We aimed to examine the prospective association between first trimester HbA1c and gestational diabetes (GDM) and explore the utility of HbA1c for prediction of GDM. We used data from a case-control study within the prospective NICHD Fetal Growth Studies-Singleton Cohort (2009-2013), which enrolled 2,802 women at 12 U.S. clinical centers. HbA1c was measured in GDM cases (n = 107) and matched controls (n = 214) targeted at 8-13, 16-22, 24-29, and 34-37 gestational weeks. We excluded women with HbA1c ≥ 6.5% (48 mmol/mol) at enrollment (n = 3) or who had a hemoglobin variant (n = 6). At 8-13 gestational weeks, women who later developed GDM had significantly higher HbA1c (5.3[standard deviation 0.3]%; 34[4]mmol/mol) than women without GDM (5.1[0.3]%; 32[3] mmol/mol) (P ≤ 0.001); this difference remained significant throughout pregnancy. Each 0.1% (1 mmol/mol) HbA1c increase at 8-13 weeks was associated with an adjusted 22% increased GDM risk (95% confidence interval 1.09-1.36). First trimester HbA1c significantly improved GDM prediction over conventional risk factors (AUC 0.59 vs 0.65; P = 0.04). In conclusion, women who develop GDM may have impaired glucose homeostasis early in or prior to pregnancy, as indicated by their elevated first trimester HbA1c. First trimester HbA1c may aid in early identification of at risk women.

Early diabetes screening in pregnancy

The present literature review was conducted to evaluate early diabetes screening in pregnancy. The review focuses on the various guidelines for early screening, the target populations for screening, and the assessment of various early screening targets and strategies. The advantages and disadvantages of each screening method are highlighted. The review emphasizes that there are no validated criteria for selecting high-risk pregnant women for early screening. The different early screening modalities, including fasting plasma glucose, random plasma glucose, postload glucose, and hemoglobin A1c, lack concordance and have not been validated for the early diagnosis of diabetes in pregnancy. Moreover, the benefit of early screening by earlier initiation of treatment has not been shown. Until a randomized controlled trial demonstrates benefit to screening and validates a particular screening method, it is not possible to provide evidence to support any single strategy for early diabetes screening in pregnancy.

The utility of HbA1c combined with haematocrit for early screening of gestational diabetes mellitus

AIMS

To evaluate the utility of glycated haemoglobin A1c (HbA1c) alone and in combination with haematocrit (HCT) for screening gestational diabetes mellitus (GDM) between 12-16 gestational weeks.

METHODS

This prospective study was carried out in the Obstetrics and Gynaecology Hospital of Fudan University from November 2014 to February 2015. In total, 690 pregnant women between 20 and 35 years old were included in this study. All subjects received a routine blood examination for HbA1c and HCT at 12-16 gestational weeks (gw) and a 75-g oral glucose tolerance test at 24-28 gw. Threshold values for the diagnosis of GDM were a plasma glucose concentration of 5.1 mmol/L after fasting, 10.0 mmol/L at 60 min, and 8.5 mmol/L at 120 min. Receiver operating characteristic curves were used to evaluate the diagnostic performance of HbA1c with or without HCT.

RESULTS

One hundred seven women were diagnosis with GDM at 24-28 gw. An HbA1c cutoff value < 4.55% at 12-16 gw showed adequate sensitivity to exclude GDM (85.0%) but low specificity (17.3%), while an HbA1c cutoff value ≥ 5.25% presented adequate specificity (96.6%) but low sensitivity (13.3%) in diagnosing GDM. The area under the receiver operating characteristic curve for HbA1c (12-16 gw) detection of GDM was 0.563 (95% confidence interval [CI], 0.50-0.625). When combined HbA1c with HCT ( > 38.8%) for the screening of GDM, the area under the receiver operating characteristic curve was 0.604 (95% [CI] 0.509, 0.701).

CONCLUSIONS

Whether the adoption of HbA1c as a screening test for GDM would benefit pregnant women remains to be determined. However, combining HbA1c with HCT for the screening of GDM may be a useful tool to predict GDM.

Controversies in Screening and Diagnostic Criteria for Gestational Diabetes in Early and Late Pregnancy

This review serves to evaluate the screening and diagnostic strategies for gestational diabetes and overt diabetes in pregnancy. We focus on the different early screening and diagnostic approaches in first trimester including fasting plasma glucose, random plasma glucose, oral glucose tolerance test, hemoglobin A1c, risk prediction models and biomarkers. Early screening for gestational diabetes is currently not recommended since the potential benefits and harms of early detection and subsequent treatment need to be further evaluated in randomized controlled trials.

Is first-trimester HbA1c useful in the diagnosis of gestational diabetes?

AIMS

To evaluate the usefulness and efficacy of first-trimester HbA1c in the diagnosis of gestational diabetes (GDM).

METHODS

Prospective observational of consecutive pregnant women. All women had a first-trimester HbA1c determination and GDM screening at 24-28weeks of pregnancy using a two-step approach. A ROC curve was drawn to determine the sensitivity and specificity of HbA1c in detecting GDM and a rule-in rule-out diagnostic algorithm was proposed. The cost of the proposed algorithm was calculated.

RESULTS

152 (13.1%) of 1195 women were diagnosed of GDM. The area under the ROC curve for HbA1c to detect GDM was 0.679 (95%CI 0.631-0.727). A rule-out threshold for HbA1c of 4.8% (29mmol/mol) had 96.7% sensitivity (95%CI 93.9-99.5), 10.1% specificity (95%CI 8.3-12.0) and a negative predictive value of 95.3% (95%CI 91.3-99.3). A rule-in value of 5.6% (38mmol/mol) had a positive predictive value of 31.6% (95%CI 24.4-38.9), 89.3% specificity (95%CI 87.4-91.2) and 32.9% sensitivity (95%CI 25.4-40.4). The low positive predictive value of the rule-in threshold precludes its use for GDM diagnosis, but could be used to identify women at high risk of GDM in whom the diagnosis can be established using a one-step approach. The overall saving of the proposed algorithm would be 6.5% of the total cost with the standard strategy.

CONCLUSIONS

A first-trimester HbA1c does not have sufficient sensitivity or specificity to diagnose GDM, although the use of a higher and lower threshold could simplify the diagnostic process by reducing the number of oral glucose tolerance test, associated costs and patient inconvenience.

Screening and Treatment for Early-Onset Gestational Diabetes Mellitus: a Systematic Review and Meta-analysis

We conducted a systematic review to evaluate the current evidence for screening and treatment for early-onset gestational diabetes mellitus (GDM) RECENT FINDINGS: Many of the women with early GDM in the first trimester do not have evidence of hyperglycemia at 24-28 weeks' gestation. A high proportion (15-70%) of women with GDM can be detected early in pregnancy depending on the setting, criteria used and screening strategy. However, there remains no good evidence for any of the diagnostic criteria for early-onset GDM. In a meta-analysis of 13 cohort studies, perinatal mortality (relative risk (RR) 3.58 [1.91, 6.71]), neonatal hypoglycemia (RR 1.61 [1.02, 2.55]), and insulin use (RR 1.71 [1.45, 2.03]) were greater among early-onset GDM women compared to late-onset GDM women, despite treatment. Considering the high likelihood of benefit from treatment, there is an urgent need for randomized controlled trials that investigate any benefits and possible harms of treatment of early-onset GDM.

Early Pregnancy Biochemical Predictors of Gestational Diabetes Mellitus

PURPOSE OF REVIEW

Universal oral glucose tolerance-based screening is employed to identify pregnant women with gestational diabetes mellitus (GDM), as treatment of this condition decreases the risk of associated complications. A simple and accurate blood test which identifies women at low or high risk for GDM in the first trimester would have the potential to decrease costs and improve outcomes through prevention or treatment. This review summarizes published data on early pregnancy biomarkers which have been tested as predictors of GDM.

RECENT FINDINGS

A large number of first-trimester biochemical predictors of GDM have been reported, mostly in small case-control studies. These include glycemic markers (fasting glucose, post-load glucose, hemoglobin A1C), inflammatory markers (C-reactive protein, tumor necrosis factor-alpha), insulin resistance markers (fasting insulin, sex hormone-binding globulin), adipocyte-derived markers (adiponectin, leptin), placenta-derived markers (follistatin-like-3, placental growth factor, placental exosomes), and others (e.g., glycosylated fibronectin, soluble (pro)renin receptor, alanine aminotransferase, ferritin). A few large studies suggest that first-trimester fasting glucose or hemoglobin A1C may be useful for identifying women who would benefit from early GDM treatment. To translate the findings from observational studies of first-trimester biomarkers for GDM to clinical practice, trials or cost-effectiveness analyses of screening and treatment strategies based on these novel biomarkers are needed.

An Unbiased Lipidomics Approach Identifies Early Second Trimester Lipids Predictive of Maternal Glycemic Traits and Gestational Diabetes Mellitus

OBJECTIVE

To investigate the relationship between early second trimester serum lipidomic variation and maternal glycemic traits at 28 weeks and to identify predictive lipid biomarkers for gestational diabetes mellitus (GDM).

RESEARCH DESIGN AND METHODS

Prospective study of 817 pregnant women (discovery cohort, n = 200; validation cohort, n = 617) who provided an early second trimester serum sample and underwent an oral glucose tolerance test (OGTT) at 28 weeks. In the discovery cohort, lipids were measured using direct infusion mass spectrometry and correlated with OGTT results. Variable importance in projection (VIP) scores were used to identify candidate lipid biomarkers. Candidate biomarkers were measured in the validation cohort using liquid chromatography-mass spectrometry and tested for associations with OGTT results and GDM status.

RESULTS

Early second trimester lipidomic variation was associated with 1-h postload glucose levels but not with fasting plasma glucose levels. Of the 13 lipid species identified by VIP scores, 10 had nominally significant associations with postload glucose levels. In the validation cohort, 5 of these 10 lipids had significant associations with postload glucose levels that were independent of maternal age and BMI, i.e., TG(51.1), TG(48:1), PC(32:1), PCae(40:3), and PCae(40:4). All except the last were also associated with maternal GDM status. Together, these four lipid biomarkers had moderate ability to predict GDM (area under curve [AUC] = 0.71 ± 0.04, P = 4.85 × 10-7) and improved the prediction of GDM by age and BMI alone from AUC 0.69 to AUC 0.74.

CONCLUSIONS

Specific early second trimester lipid biomarkers can predict maternal GDM status independent of maternal age and BMI, potentially enhancing risk factor-based screening.