Gestational Diabetes Mellitus: Does One Size Fit All? A Challenge to Uniform Worldwide Diagnostic Thresholds

First-trimester proteomic profiling identifies novel predictors of gestational diabetes mellitus

Background

Gestational diabetes mellitus (GDM) is a common pregnancy complication associated with adverse outcomes including preeclampsia, caesarean section, macrosomia, neonatal morbidity and future development of type 2 diabetes in both mother and child. Current selective screening strategies rely on clinical risk factors such as age, family history of diabetes, macrosomia or GDM in a previous pregnancy, and they possess a relatively low specificity. Here we hypothesize that novel first trimester protein predictors of GDM can contribute to the current selective screening strategies for early and accurate prediction of GDM, thus allowing for timely interventions.

Methods

A proteomics discovery approach was applied to first trimester sera from obese (BMI ≥27 kg/m²) women (n = 60) in a nested case-control study design, utilizing tandem mass tag labelling and tandem mass spectrometry. A subset of the identified protein markers was further validated in a second set of serum samples (n = 210) and evaluated for their contribution as predictors of GDM in relation to the maternal risk factors, by use of logistic regression and receiver operating characteristic analysis.

Results

Serum proteomic profiling identified 25 proteins with significantly different levels between cases and controls. Three proteins; afamin, serum amyloid P-component and vitronectin could be further confirmed as predictors of GDM in a validation set. Vitronectin was shown to contribute significantly to the predictive power of the maternal risk factors, indicating it as a novel independent predictor of GDM.

Conclusions

Current selective screening strategies can potentially be improved by addition of protein predictors.

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.

The first-trimester of pregnancy - A window of opportunity for prediction and prevention of pregnancy complications and future life

The International Federation of Gynecology and Obstetrics (FIGO) has identified non communicable maternal diseases (NCDs) as a new focus area. NCDs and exposures as related to pregnancy complications and later impairment of maternal and offspring health will form the basis for action in the forthcoming years. This paper summarizes recent advances, centered on the use of first-trimester testing, as a window of opportunity to predict and prevent many pregnancy complications; and for potential future prevention of NCDs in mother and offspring. Recent results from a large-scale randomized control trial have provided definitive proof that effective screening for preterm preeclampsia (preterm-PE), requiring delivery before 37 weeks' gestation, can be achieved with a combined test of maternal factors and biomarkers at 11-13 weeks and that aspirin, given to high-risk women, is effective in reducing the risk of preterm-PE and the length of stay in neonatal intensive care unit. This is the first successful example to illustrate that pregnancy complications is predictable and preventable in early pregnancy. Similar prediction and prevention strategies are being developed for hyperglycemia in pregnancy and preterm birth, with the intention for longer lasting interventions leading to significant downstream impact in improving long-term health in both mothers and babies.

Lifestyle Intervention in Danish Obese Pregnant Women With Early Gestational Diabetes Mellitus According to WHO 2013 Criteria Does Not Change Pregnancy Outcomes: Results From the LiP (Lifestyle in Pregnancy) Study

OBJECTIVE

To study effects of lifestyle intervention on metabolic and clinical outcomes in obese women fulfilling the World Health Organization (WHO) 2013 diagnostic criteria for gestational diabetes mellitus (GDM) in early gestation.

RESEARCH DESIGN AND METHODS

Secondary analysis of data from the Lifestyle in Pregnancy (LiP) study, a lifestyle randomized controlled trial in 304 pregnant women with BMI ≥30 kg/m². Early GDM (week 12-15) was diagnosed according to modified WHO 2013 GDM criteria: fasting venous plasma glucose ≥5.1 mmol/L and/or 2-h capillary blood glucose (CBG) ≥8.5 mmol/L (75-g oral glucose tolerance test [OGTT]). Women with treated GDM fulfilling local Danish GDM criteria (2-h CBG ≥9.0 mmol/L) (n = 16) and women with normal OGTT (n = 198) were excluded.

RESULTS

Of 90 women with early GDM, 36 received lifestyle intervention and 54 standard care. All were Caucasian, and median age was 29 years (interquartile range 27-33) and BMI 34.5 kg/m² (32.3-38.1). All baseline characteristics were similar in the lifestyle intervention and standard care groups. At gestational week 28-30, the women in the lifestyle intervention group had significantly higher fasting total cholesterol and fasting LDL. All other metabolic parameters including measurements of glucose, insulin, and HOMA of insulin resistance were similar. There were more planned cesarean sections in the lifestyle intervention group (22.2 vs. 5.6%), but all other obstetric outcomes were similar.

CONCLUSIONS

Lifestyle intervention in obese women fulfilling WHO 2013 GDM criteria in early pregnancy was not effective in improving obstetric or metabolic outcomes. Future studies should focus on interventions starting prepregnancy.

Maternal Lipids and Fetal Overgrowth: Making Fat from Fat

There is increasing recognition that maternal glucose concentrations lower than those previously used for diagnosis of gestational diabetes mellitus (GDM) and targeted for treatment can result in excess fetal growth. Yet, mothers with GDM who appear to have optimal glycemic control and mothers with obesity and normal glucose tolerance still have a significantly increased risk for delivering infants who are large for gestational age, or even more importantly, who have increased adiposity at birth. What is less appreciated is that in addition to glucose, maternal lipids are also substrates for fetal fat accretion and that placental lipases can hydrolyze maternal triglycerides (TGs) to free fatty acids for fetal-placental availability. Maternal TG levels are 40% to 50% higher on average in mothers with obesity and GDM compared to those in normal-weight mothers early in pregnancy and are sustained at higher levels throughout gestation. Increasing evidence supports that maternal TG, both fasting and postprandial, are also predictors of newborn adiposity (newborn %fat), a risk factor for childhood obesity, and that early exposure is at least as strong of a risk factor as later exposure in mothers with obesity. In the setting of maternal nutrient excess and maternal insulin resistance, which lead to fetal hyperinsulinemia, excess free fatty acid exposure in the fetus may result in lipid storage and fetal fat development in subcutaneous and possibly other depots. In this commentary, we provide further evidence to make a case for targeting maternal fasting and postprandial TG in mothers with obesity who have elevated TG in early pregnancy to determine whether a TG-lowering interventional approach might limit fetal overgrowth and potentially mitigate the intrauterine contribution to childhood obesity and metabolic disease.

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.

Diagnosis and follow-up of type 2 diabetes in women with PCOS: a role for OGTT?

Polycystic ovary syndrome (PCOS) is common in premenopausal women. The majority of women with PCOS have insulin resistance and the risk of type 2 diabetes mellitus (T2D) is higher in women with PCOS compared to controls. In non-pregnant women with PCOS, glycemic status may be assessed by oral glucose tolerance test (OGTT), fasting plasma glucose (FPG) or HbA1c. OGTT has been reckoned gold standard test for diagnosing T2D, but OGTT is rarely used for diagnostic purpose in other non-pregnant individuals at risk of T2D, apart from PCOS. OGTT has questionable reproducibility, and high sensitivity of the 2-h glucose value is at the expense of relatively low specificity, especially regarding impaired glucose tolerance (IGT). Furthermore, lean women with PCOS are rarely diagnosed with T2D and only few percent of normal-weight women have prediabetes. Glycemic status is necessary at diagnosis and during follow-up of PCOS, especially in women with high risk of T2D (obesity, previous gestational diabetes (GDM)). We suggest that OGTT should be used in the same situations in PCOS as in other patient groups at risk of T2D. OGTT is indicated for diagnosing GDM; however, OGTT during pregnancy may not be indicated in lean women with PCOS without other risk factors for GDM.

Ethnic Disparities in Gestational Diabetes

PURPOSE OF REVIEW

Ethnicity has long been described as a major risk factor for the development of gestational diabetes mellitus (GDM), and it is widely recognised that women from ethnicities other than Europids are at higher risk of developing GDM. There are also described differences between ethnicities in key GDM pregnancy outcomes. This review describes some of the factors that relate to the ethnic disparities in GDM.

RECENT FINDINGS

The global prevalence of GDM has been steadily increasing and estimated to be 16.2% from the International Diabetes Federation extrapolation. Reported prevalence rates may understate the true prevalence, due to factors of access and attitudes to GDM diagnosis and screening in low resource settings for foreign-born women and indigenous populations. Other factors may relate to genes associated with specific ethnicities, obesity, body composition and gestational weight gain. Various factors such as access to screening, body composition, genetics and gestational weight gain may result in ethnic disparities in the prevalence and outcomes of GDM.

Comparing Different Diagnostic Guidelines for Gestational Diabetes Mellitus in Relation to Birthweight in Sri Lankan Women

Introduction: While the International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria is widely adopted in many countries, clinicians have questioned the applicability of these diagnostic thresholds for different races/ethnicities. We first compared the prevalence of gestational diabetes mellitus (GDM) diagnosed with different criteria including IADPSG, World Health Organization (WHO) 1999 and Sri Lankan national guidelines, and subsequently related individual guidelines-specific GDM prevalence to offspring birthweight in Sri Lanka. Materials and Methods: We retrospectively collected data on singleton pregnancies (n = 795) from two tertiary hospitals in Sri Lanka. We applied three diagnostic guidelines to define GDM, namely IADPSG criteria, the Sri Lankan national and WHO 1999 guidelines. We calculated the age- and first booking BMI-adjusted prevalence rates of GDM and assessed the association of GDM (using each guideline) with birthweight. Results: The age- and first booking BMI-adjusted GDM prevalence rates were 31.2, 28.0, and 13.1% for IADPSG criteria, Sri Lankan national and WHO 1999 guidelines, respectively. The IADPSG criteria identified 90 distinctive GDM cases at a lower cut-off of fasting glucose (from 5.1 to 5.5 mmol/L) while Sri Lankan national guideline identified 15 distinctive GDM cases at a lower cut-off for 2-h glucose (from 7.8 to 8.4 mmol/L). After adjusting for age, GDM diagnosed by IADPSG criteria was associated with higher birthweight [90.8 g, 95% CI: 10.8, 170.9], while the associations for GDM diagnosed either by Sri Lankan national or WHO 1999 guidelines were not significant. Conclusion: Adopting the IADPSG criteria for diagnosing GDM may be important in Sri Lankan pregnant population.