Screening for gestational diabetes: a systematic review and meta-analysis

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..

The screening performance of glucose challenge test for gestational diabetes in twin pregnancies: a systematic review and meta-analysis

BACKGROUND

The screening accuracy of the 50 g-glucose challenge test (50 g-GCT) for gestational diabetes (GDM) has been described in singleton pregnancies. Given the physiologic differences and greater increase in insulin resistance in twin compared with singleton pregnancies, the performance of the 50 g-GCT in twin pregnancies may differ.

OBJECTIVES

To perform a systematic review on the screening performance of the 50 g-GCT for gestational diabetes in twin pregnancies.

DATA SOURCES

Ovid Medline, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL).

STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, AND INTERVENTIONS

We included randomized controlled trials or cohort studies that evaluated the screening accuracy of the 50 g-GCT for GDM in twin pregnancies using the two-step approach. The primary outcome was the positive predictive value of the 50 g-GCT for GDM using the 140 mg/dL (7.8 mmol/L) threshold.

STUDY APPRAISAL AND SYNTHESIS METHODS

Methodological quality of included studies was assessed using the QUADAS-2 tool. The positive predictive value (PPV) was pooled for studies that used similar test characteristics.

RESULTS

From 2044 citations, 7 retrospective cohort studies with a total of 55,597 participants were included (6.5% twins and 93.5% singletons). The majority of studies evaluated a 50-g GCT cutoff point of 140 mg/dL. The pooled PPV for a threshold of 140 mg/dL (7.8 mmol/L) for twins was 22.58% (95% CI: 0.1912-0.2647, I²=34.1%). The 50-g GCT screen positive rate in twin pregnancies was higher than that in singleton pregnancies. None of the studies performed routine OGTT.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

The PPV of 50 g-GCT for GDM in twin pregnancies when using a threshold of 140 mg/dL (7.8 mmol/L) is approximately 23%. There is currently no data on the sensitivity and specificity of the 50 g-GCT in twins.

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.

A systematic review and meta-analysis of the prevalence and determinants of gestational diabetes mellitus in Nigeria

BACKGROUND

Gestational diabetes mellitus (GDM) is any degree of glucose intolerance with onset or first diagnosis in pregnancy. GDM has numerous potential complications and it is important to estimate its burden and risk factors. The objective of the meta-analysis was to determine the pooled prevalence of GDM in Nigeria and identify its determinants.

METHODS

The study design was a meta-analysis; therefore the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Electronic databases (African Journal Online, PubMed, SCOPUS, and Google Scholar) and the gray literature were systematically searched. Statistical analysis was done with MetaXL using the random effect model. Heterogeneity was determined using the I2 statistic and the publication bias was checked with the Doi plot.

RESULTS

The total sample size was 46 210. The prevalence of GDM in Nigeria was 0.5 - 38% and the pooled prevalence was 11.0% (95% CI 8-13). The I2 statistic was 99%. The Doi plot suggested some degree of bias. The most frequently reported determinants of GDM were previous macrosomic babies, maternal obesity, family history of diabetes, previous miscarriage, and advanced maternal age.

CONCLUSION

The prevalence of GDM in Nigeria is high and efforts should be geared at modifying its risk factors so as to reduce its prevalence and prevent the associated complications.

Accuracy of screening tests for gestational diabetes mellitus in Southeast Asia: A systematic review of diagnostic test accuracy studies

BACKGROUND

To investigate the accuracy of screening tests for gestational diabetes mellitus (GDM) in Southeast Asian pregnant women.

METHODS

We searched PubMed (MEDLINE), Web of Science, Cochrane Library, ClinicalTrials.gov, Google Scholar, and Google for relevant articles published in English up to November 2018 using search terms related to GDM, screening tests for GDM and diagnostic performance. The studies were independently screened and selected by both authors. The methodological quality of the included studies was independently assessed by quality assessment of diagnostic accuracy studies 2. A hierarchical summary receiver operating characteristic (HSROC) model was created to estimate the HSROC curve. The summary sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were calculated in a meta-analysis using bivariate random-effects model.

RESULTS

A total of 19 studies were included in which the 100 g oral glucose tolerance test (OGTT) and 75 g OGTT were the two common reference standards for diagnosis of GDM. Most points of diagnostic performance in the HSROC 50 g GCT curve compared with the 100 g OGTT reference standard were clustered in the upper left-hand quadrant. The pooled sensitivity and specificity of the 50 g GCT were 79% (95% confidence interval [CI] 64%-89%) and 74% (95% CI 59%-85%), respectively. For the 75 g OGTT reference standard, the non-fasting 2-hour plasma glucose showed quite similar sensitivity the 50 g GCT compared with the 100 g OGTT reference standard. The pooled sensitivities and specificities of the fasting plasma glucose and hemoglobin A1c were 81% (95% CI 76%-86%) and 70% (95% CI 67%-72%), and 80% (95% CI 66%-90%) and 69% (95% CI 58%-78%), respectively.

CONCLUSION

Our findings indicate that the 50 g GCT using the threshold of 140 mg/dL is a good screening test for identifying GDM at 24 to 28 weeks' gestational age for both high-risk and universal screening strategies in Southeast Asian countries. The non-fasting 2-hour PG, fasting plasma glucose or hemoglobin A1c are alternative choices for screening.

Cost effectiveness of different screening strategies for gestational diabetes mellitus screening: study protocol of a randomized community non-inferiority trial

BACKGROUND

There is lack of ideal and comprehensive economic evaluations of various GDM strategies. The aim of this study is to the compare efficacy and cost-effectiveness of five different methods of screening for gestational diabetes mellitus (GDM).

METHODS

This study is a randomized community non-inferiority trial among 30,000 pregnant women in five different geographic regions of Iran, who were randomly assigned to one of the five GDM screening methods. All first trimester pregnant women, seeking prenatal care in governmental health care systems, who met our eligibility criteria were enrolled. The criteria suggested by the International-Association-of-Diabetes-in-Pregnancy-Study-Group, the most intensive approach, were used as reference. We used the non-inferiority approach to compare less intensive strategies to the reference one. Along with routine prenatal standard care, all participants were scheduled to have two phases of GDM screening in first and second-trimester of pregnancy, based on five different pre-specified protocols. The screening protocol included fasting plasma glucose in the first trimester and either a one step or a two-step screening method in the second trimester of pregnancy. Pregnant women were classified in three groups based on the results: diagnosed with preexisting pre-gestational overt diabetes; gestational diabetes and non-GDM women. Each group received packages for standard-care and all participants were followed till delivery; pregnancy outcomes, quality of life and cost of health care were recorded in detail using specific standardized questionnaires. Primary outcomes were defined as % birth-weight > 90th percentile and primary cesarean section. In addition, we assessed the direct health care direct and indirect costs.

RESULTS

This study will enable us to compare the cost effectiveness of different GDM screening protocols and intervention intensity (low versus high).

CONCLUSION

Results which if needed, will also enable policy makers to optimize the national GMD strategy as a resource for enhancing GDM guidelines.Trial registration Name of the registry: Iranian Registry of Clinical Trials. Trial registration number: IRCT138707081281N1. Date of registration: 2017-02-15. URL of trial registry record: https://www.irct.ir/trial/518.

Polycystic ovary syndrome and hyperglycaemia in pregnancy. A narrative review and results from a prospective Danish cohort study

BACKGROUND

Insulin resistance is common in polycystic ovary syndrome (PCOS). PCOS may be associated with increased risk of gestational diabetes mellitus (GDM).

OBJECTIVES

To (1) review literature regarding PCOS and hyperglycaemia in pregnancy and (2) present original data from Odense Child Cohort (OCC) regarding GDM in PCOS.

METHODS

Literature search including original studies from 2000-18. OCC included 2548 pregnant women, 9.5% (n = 241) had PCOS. Fasting plasma glucose was measured in 1519 and 659 oral glucose tolerance tests were performed (with risk factor for GDM, n = 384, without risk factors, n = 275), applying two different GDM criteria.

RESULTS

30 studies were eligible using 12 different sets of diagnostic criteria for GDM. Ten studies included n > 50, control group, assessment of GDM and BMI. Results were not uniform, but supported that higher BMI, higher age, Asian ethnicity, and fertility treatment increased the risk of GDM in PCOS. In OCC, women with PCOS and controls had similar prevalences of GDM independent of different sets of criteria for GDM.

CONCLUSION

PCOS may not be an individual risk factor for GDM. Pregnancies in PCOS are characterized by factors known to increase risk of GDM, especially high BMI and fertility treatment.

Gestational Diabetes - Major New Clinically Relevant Aspects

The implementation of screening for gestational diabetes (GDM) in the German Prenatal Care guidelines of 2012 and the publication of numerous new studies have led to clinically relevant changes in the care of pregnant women with GDM to whom consideration was given in the new S3 Guideline on the Diagnosis, Management and Follow-up of Gestational Diabetes (AWMF 057/008) published in March this year. Certain aspects are addressed and discussed on the basis of additional background information.

Fasting glucose in the first trimester: An initial approach to diagnosis of gestational diabetes

OBJECTIVES

To establish whether fasting glucose levels in the first trimester (FGFT)of pregnancy ≥ 92 mg/dL (5.1 mmol/L) (FGFT) anticipate the occurrence of maternal-fetal complications of gestational diabetes mellitus. To assess whether FGFT can replace diagnosis of GDM using the classical two-step oral glucose tolerance test (OGTT).

METHODS

A retrospective study of 1425 pregnancies with FGFT and O'Sullivan Test (OST) and/or OGTT according to OST results in the second trimester. FGFT sensitivity and specificity were assessed as compared to the conventional diagnosis of GDM. The relationship between maternal-fetal complications and FGFT was assessed in the total group and after excluding mothers who received specific medical treatment for GDM.

RESULTS

Sensitivity and specificity of FGFT levels ≥ 92mg/dL were 46.4% and 88.8% as compared to diagnosis of GDM using Carpenter and Coustan criteria. In the total group, a statistically significant relationship was found between FGFT levels ≥ 92 mg/dL and newborn weight (3228±86 versus 3123±31g; P<.05), as well as a higher rate of macrosomia (6.9% versus 3.5%; P<.05). This association persisted after excluding patients diagnosed with and treated for GDM (weight: 3235±98 versus 3128±31 g; P<.05; percentage of macrosomia: 7.2% versus 3.4%; P<.05).

CONCLUSIONS

FGFT is not a good substitute for conventional diagnosis of GDM in the second trimester. Pregnant women with FGFT levels ≥ 92 mg/dL, even with no subsequent diagnosis of GDM, are a risk group for fetal macrosomia and could benefit from dietary measures and physical exercise.

Prevalence of Adverse Pregnancy Outcomes, by Maternal Diabetes Status at First and Second Deliveries, Massachusetts, 1998-2007

Introduction

Understanding patterns of diabetes prevalence and diabetes-related complications across pregnancies could inform chronic disease prevention efforts. We examined adverse birth outcomes by diabetes status among women with sequential, live singleton deliveries.

Methods

We used data from the 1998–2007 Massachusetts Pregnancy to Early Life Longitudinal Data System, a population-based cohort of deliveries. We restricted the sample to sets of parity 1 and 2 deliveries. We created 8 diabetes categories using gestational diabetes mellitus (GDM) and chronic diabetes mellitus (CDM) status for the 2 deliveries. Adverse outcomes included large for gestational age (LGA), macrosomia, preterm birth, and cesarean delivery. We computed prevalence estimates for each outcome by diabetes status.

Results

We identified 133,633 women with both parity 1 and 2 deliveries. Compared with women who had no diabetes in either pregnancy, women with GDM or CDM during any pregnancy had increased risk for adverse birth outcomes; the prevalence of adverse outcomes was higher in parity 1 deliveries among women with no diabetes in parity 1 and GDM in parity 2 (for LGA [8.5% vs 15.1%], macrosomia [9.7% vs. 14.9%], cesarean delivery [24.7% vs 31.3%], and preterm birth [7.7% vs 12.9%]); and higher in parity 2 deliveries among those with GDM in parity 1 and no diabetes in parity 2 (for LGA [12.3% vs 18.2%], macrosomia [12.3% vs 17.2%], and cesarean delivery [27.0% vs 37.9%]).

Conclusions

Women with GDM during one of 2 sequential pregnancies had elevated risk for adverse outcomes in the unaffected pregnancy, whether the diabetes-affected pregnancy preceded or followed it.

Gene Expression in Placentas From Nondiabetic Women Giving Birth to Large for Gestational Age Infants

Gestational diabetes, obesity, and excessive weight gain are known independent risk factors for the birth of a large for gestational age (LGA) infant. However, only 1 of the 10 infants born LGA is born by mothers with diabetes or obesity. Thus, the aim of the present study was to compare placental gene expression between healthy, nondiabetic mothers (n = 22) giving birth to LGA infants and body mass index-matched mothers (n = 24) giving birth to appropriate for gestational age infants. In the whole gene expression analysis, only 29 genes were found to be differently expressed in LGA placentas. Top upregulated genes included insulin-like growth factor binding protein 1, aminolevulinate δ synthase 2, and prolactin, whereas top downregulated genes comprised leptin, gametocyte-specific factor 1, and collagen type XVII α 1. Two enriched gene networks were identified, namely, (1) lipid metabolism, small molecule biochemistry, and organismal development and (2) cellular development, cellular growth, proliferation, and tumor morphology.

Calcium plus vitamin D supplementation affects pregnancy outcomes in gestational diabetes: randomized, double-blind, placebo-controlled trial

OBJECTIVE

The present study was designed to assess the effects of Ca+vitamin D supplementation on pregnancy outcomes in women with gestational diabetes mellitus (GDM).

DESIGN

A randomized, double-blind, placebo-controlled trial was conducted among sixty women with GDM. Participants were divided into two groups to receive Ca+vitamin D supplements or placebo. Individuals in the Ca+vitamin D group (n 30) received 1000 mg Ca/d and two pearls containing 1250 µg (50 000 IU) of cholecalciferol (vitamin D(3)) during the intervention (one at study baseline and another at day 21 of the intervention); those in the placebo group (n 30) received two placebos of vitamin D at the mentioned times and placebos of Ca every day for 6 weeks. Pregnancy outcomes were determined.

SETTING

A urban community setting in Arak, Iran.

SUBJECTS

Sixty women with GDM and their newborns, living in Arak, Iran were enrolled.

RESULTS

Women treated with Ca+vitamin D had a significant decrease in caesarean section rate (23·3 % v. 63·3 %, P=0·002) and maternal hospitalization (0 v. 13·3 %, P=0·03) compared with those receiving placebo. In addition, newborns of GDM women randomized to Ca+vitamin D had no case of macrosomia, while the prevalence of macrosomia among those randomized to placebo was 13·3 % (P=0·03). Lower rates of hyperbilirubinaemia (20·0 % v. 56·7 %, P=0·03) and hospitalization (20·0 % v. 56·7 %, P=0·03) were also seen in the supplemented group of newborns than in the placebo group.

CONCLUSIONS

Ca+vitamin D supplementation for 6 weeks among pregnant women with GDM led to decreased caesarean section rate and maternal hospitalization, and decreased macrosomia, hyperbilirubinaemia and hospitalization in newborns.

Association between metabolic deteriorations and prior gestational diabetes according to weight status

OBJECTIVE

The aim of the present study is to investigate the effect of prior gestational diabetes mellitus (GDM) on glucose and insulin homeostasis according to weight status.

METHODS

The analysis included 299 women, 216 with [GDM(+)] and 83 without prior GDM [GDM(-)]. The mean time between pregnancy and testing was 3.9 years. Glucose values were obtained from a 2-h 75 g oral glucose tolerance test (OGTT). Body composition was measured by dual-energy X-ray.

RESULTS

In women with normal BMI, fasting glucose, 2-h post-OGTT glucose, and HbA1 were higher for GDM(+) (P<0.05). Normal-weight women with GDM(+) presented lower HOMA-IS, insulin secretion, and insulinogenic index (P<0.05) compared to GDM(-). Body fat and android fat mass were higher, gynoid fat mass was similar, and lean body mass was decreased in GDM(+) vs. GDM(-) with normal weight (P<0.05). A greater proportion of GDM(+) with overweight/obesity had prediabetes (72.1%) or type 2 diabetes (T2D) (21.7%) vs. GDM(-) and overweight/obesity (17.1 and 2.4%) or GDM(+) and normal weight (60.5 and 14.0%).

CONCLUSIONS

A combination of GDM and overweight/obesity is associated with T2D-related metabolic deteriorations. Nevertheless, normal-weight women with GDM(+) had increased android fat and greater metabolic complications, suggesting that women with prior GDM should benefit from lifestyle intervention, regardless of their weight status.

Lower treatment targets for gestational diabetes: is lower really better?

Proposed lower diagnostic thresholds and lower treatment targets for gestational diabetes have been controversial internationally. Intervention trials for the recently revised lower Australian treatment targets are currently lacking. While there may be benefits, lowering treatment targets may cause a number of harms including increased risk of hypoglycaemia in pregnant women, greater medicolegal risk for health practitioners, and heavier economic costs for the health system. Regional and remote care providers in particular will have greater costs, and may be overwhelmed in attempts to implement new treatment targets. An excessively glucose-centric focus may divert attention and resources from identifying and addressing other important and growing contributors to adverse pregnancy outcomes, such as obesity. Important groups such as Aboriginal and Torres Strait Islander Australians may not gain overall benefit from lowering treatment targets for gestational diabetes because of current low birthweights and the effect of social costs. It has not yet been established whether implementing lower treatment targets for gestational diabetes will create more benefit than harm. Implementation at this stage is premature.

Screening and management of gestational diabetes

Gestational diabetes (GDM) is a frequent medical condition during pregnancy. It is associated with an increased risk of complications for both the mother and the baby during pregnancy and post partum. The International Association of Diabetes and Pregnancy Study Groups (IADPSG) has proposed a new screening strategy for overt diabetes in pregnancy and screening for GDM. However, there is still a lack of international uniformity in the approach to the screening and diagnosis of GDM. Controversies include universal versus selective screening, the optimal time for screening, appropriate tests and cutoff values, and whether testing should be conducted in one or two steps. This review gives an update on screening for GDM and overt diabetes during pregnancy. We also give an overview on the medical and obstetrical management of GDM.

Screening for dysglycaemia during pregnancy: Proposals conciliating International Association of Diabetes and Pregnancy Study Group (IADPSG) and US National Institutes of Health (NIH) panels

The International Association of Diabetes and Pregnancy Study Group (IADPSG) has proposed that blood glucose levels for the diagnosis of gestational diabetes mellitus (GDM) be the values associated with a 1.75-fold increase in the risk of neonatal complications in the Hyperglycaemia and Adverse Pregnancy Outcomes (HAPO) study. However, this recommendation was not adopted by the US National Institutes of Health (NIH) panel as it would have been responsible for a huge increase in the prevalence of GDM with no clear evidence of a reduction of events at such blood glucose values. Considering this aspect, we now propose the use of a blood glucose threshold combination associated with an odds-ratio of 2.0 for neonatal disorders [fasting plasma glucose (FPG)≥ 95 mg/dL, or a 1-h glucose value after a 75-g oral glucose tolerance test (OGTT)≥ 191 mg/dL or a 2-h glucose value ≥ 162 mg/dL] for GDM diagnosis. This would lead to a lower prevalence of GDM and concentrate medical resources on those with the highest risk of complications. This would also allow the use of a similar FPG value for both the diagnosis and therapeutic target of GDM. The IADPSG also proposed screening for dysglycaemia during early pregnancy, using FPG measurement with a similar threshold after 24 weeks of gestation. We propose the same strategy considering an FPG value ≥ 95 mg/dL as abnormal, but only after confirmatory measurements. We also believe that an OGTT should not be used before 24 weeks of gestation as normal values during that time are as yet unknown.

Fasting plasma glucose to avoid a full OGTT in the diagnosis of gestational diabetes

AIMS

To evaluate the performance of fasting plasma glucose (FPG) in determining the need for a full oral glucose tolerance test (OGTT) to diagnose gestational diabetes (GDM) by the International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria.

METHODS

A multicenter cohort study of 4926 pregnant women 20 years or older consecutively enrolled in prenatal care clinics of the Brazilian National Health Service from 1991 to 1995. All women underwent a single 2 h 75 g OGTT by weeks 24-28 of pregnancy and were followed to detect adverse pregnancy outcomes.

RESULTS

A FPG cut-off value of 80 mg/dl indicated that only 38.7% of all women needed to undergo a complete OGTT, while detecting 96.9% of all GDM cases. When the 85 mg/dl cut-off was used, the corresponding percentages were 18.7% and 92.5%, respectively. The fraction of women labeled with GDM who had adverse pregnancy outcomes was nearly identical when using FPG strategies and universal full testing.

CONCLUSIONS

Using a FPG cut-off to diagnose GDM and to determine the need for post-load OGTT measurements is a valid strategy to diagnose GDM by IADPSG criteria. This approach may improve feasibility of applying IADPSG diagnostic criteria by reducing costs and increasing convenience.