Diabetes in pregnancy: glycemia control guidelines and rationale

Fasting blood glucose as a screening measure for late-onset gestational diabetes in the third trimester

OBJECTIVE

To investigate the positive rate of late-onset gestational diabetes mellitus (GDM) by additional fasting blood glucose (FBG) screening at 32-34 gestational weeks (GW) and analyse the perinatal outcomes of late-onset GDM after standard treatment.

DESIGN

An Prospective cohort study.

SETTING

Single centre in China.

POPULATION

1130 singleton pregnancies with negative GDM screening in their first and second trimester.

METHODS

Additional FBG testing was performed at 32-34 GW. Pregnancies with FBG ≥5.1 mmol/L were diagnosed as GDM and received standardized treatment. Perinatal outcomes were collected and compared.

MAIN OUTCOME MEASURES

Diagnosis of late-onset GDM, obstetric and neonatal outcomes.

RESULTS

6.3% (71/1130) of participants had FBG values ≥5.1 mmol/L and were diagnosed with late-onset GDM. Sixty-five (91.5%) were treated by dietary therapy and 6 (8.5%) by insulin therapy. The perinatal outcomes of full-term delivery were compared. The incidence of macrosomia (22.7% vs. 5.1%, adjusted odds ratio (aOR) 5.51, 95% confidence interval (CI) 1.83-16.61, p = 0.002) and NICU transferring (18.3% vs. 10.1%, aOR 1.94, 95% CI 1.01-3.74, p = 0.046) was significantly higher in late-onset GDM group than that in FBG <5.1 mmol/L group. Elevated FBG was associated with overweight or obesity during pregnancy (54.9% vs. 34.9%, OR 2.27, 95% CI 1.40-3.68, p = 0.001).

CONCLUSIONS

6.3% of singleton pregnancies with normal GDM screening results in the first and second trimester were found to have late-onset GDM by additional FBG screening at 32-34 GW, and their risk of macrosomia during a full-term pregnancy remains significantly higher after standard treatment.

Diagnostic Biomarkers for Gestational Diabetes Mellitus Using Spectroscopy Techniques: A Systematic Review

Gestational diabetes mellitus (GDM) is associated with adverse maternal and foetal consequences, along with the subsequent risk of type 2 diabetes mellitus (T2DM) and several other diseases. Due to early risk stratification in the prevention of progression of GDM, improvements in biomarker determination for GDM diagnosis will enhance the optimization of both maternal and foetal health. Spectroscopy techniques are being used in an increasing number of applications in medicine for investigating biochemical pathways and the identification of key biomarkers associated with the pathogenesis of GDM. The significance of spectroscopy promises the molecular information without the need for special stains and dyes; therefore, it speeds up and simplifies the necessary ex vivo and in vivo analysis for interventions in healthcare. All the selected studies showed that spectroscopy techniques were effective in the identification of biomarkers through specific biofluids. Existing GDM prediction and diagnosis through spectroscopy techniques presented invariable findings. Further studies are required in larger, ethnically diverse populations. This systematic review provides the up-to-date state of research on biomarkers in GDM, which were identified via various spectroscopy techniques, and a discussion of the clinical significance of these biomarkers in the prediction, diagnosis, and management of GDM.

[Effects of nursing intervention programs for women with gestational diabetes: a systematic review of randomized controlled trials]

Purpose

This study aimed to identify the effects of nursing intervention programs for women with gestational diabetes mellitus (GDM) through a critical review of recent studies.

Methods

Studies related to effects of nursing intervention programs for women with GDM published in English or Korean between 2000 and 2019 were extracted from 10 electronic databases. The quality of the studies was evaluated and double-checked for accuracy by two reviewers using the Revised Cochrane Risk-of-Bias tool for randomized controlled trials.

Results

Twenty studies were selected, of which 19 had a low risk of bias and one had a high risk of bias. Interventions fell into six main groups: (1) integrated interventions, (2) self-monitoring of blood glucose levels, (3) dietary interventions, (4) exercise, (5) psychotherapy, and (6) complementary therapy. This review found that nursing interventions for GDM were of many types, and integrated interventions were the most common. However, low-carbohydrate diets and blood glucose monitoring interventions did not show statistically significant results. Evidence shows that various nursing intervention programs applied to GDM improved diverse aspects of maternal, fetal, and neonatal health, including both physical and psychological aspects.

Conclusion

The composition and delivery of integrated interventions continue to evolve, and these interventions affect physical and psychological indicators. Although interventions affecting physical health indicators (e.g., blood glucose levels, diet, and exercise) are important, many studies have shown that programs including psycho-emotional nursing interventions related to anxiety, depression, stress, self- efficacy, and self-management are also highly useful.

Abnormal glucose tolerance later in life in women affected by glucose intolerance during pregnancy

Gestational diabetes mellitus (GDM) is a condition of abnormal maternal glucose tolerance that occurs, or is detected, for the first time during pregnancy. The new diagnostic strategies recommend a 75 g, 2-h glucose tolerance test for all women not already known to be diabetic, in the early 3rd trimester of pregnancy. GDM is diagnosed when one or more values is equal to or exceeds the thresholds suggested (i.e. fasting ≥ 5.1 mmol/l, 1-h ≥ 10.0 mmol/l and 2-h ≥ 8.5 mmol/l). This criteria will determine a significant increase of the prevalence of GDM, primarily because only one abnormal value (OAV), not two, is sufficient to make the diagnosis. We also suppose that the new cases of gestational diabetes diagnosed with the new criteria will have an increased risk for subsequent abnormal glucose tolerance later in life, as it was largely confirmed in the past for the patients with two or more abnormal values.

Investigating the effects of treatment based on single high blood glucose in gestational diabetes screening on maternal and neonatal complications

PURPOSE

To create a positive step toward achieving an efficient method for gestational diabetes treatment, the present study was carried out to compare the treatment outcomes based on single impaired blood glucose versus regular method in health care centers in Iran.

METHODS

This randomized clinical trial was carried out in Tehran/Iran between March 2012 and August 2013. Study sample consisted of mothers whose fasting blood sugar was disturbed or a disturbed blood sugar was seen in OGTT with 75 g glucose load, according to ADA standards. For each outcome, multiple logistic regressions were used to control for the effects of potential confounders. When a confounder was measured on a continuous scale (e.g., age), LOWESS (locally weighted scatter plot smoothing) algorithm was used to determine whether the effect of that variable was linear. We also used the fractional polynomial regression to determine the optimal transformation of continuous covariates.

RESULTS

The information of 189 pregnant women was used in this study; 87 in the interventional group (46 %) and 102 in the control group (54 %). Treatment based on the new protocol has very high protective effect (OR 0.25, 95 % CI 0.68-0.88) in terms of neonatal hyperbilirubinemia. This difference was not seen in other outcomes including stillbirth, macrosomic newborn delivery, hypoglycemia, and hypocalcemia. The risk of neonatal hypoglycemia reduced after the 25th week of gestation (OR 0.39, 95 % CI 0.15-0.98).

CONCLUSIONS

Although the treatment of mild gestational diabetes could not significantly decrease severe neonatal outcomes, it did significantly reduce the risk of hyperbilirubinemia and its subsequent complications.

Recent advances in the diagnosis and management of gestational diabetes

Gestational diabetes is a condition which is seen in 7% of pregnancies and have potential risks for both mother and fetus. Despite its importance, there is not any golden standard approaches to the diagnosis and management of the disease. The aim of this review was to investigate the advances in the diagnosis and management of gestational diabetes in recent years.

Retardation of fetal dendritic development induced by gestational hyperglycemia is associated with brain insulin/IGF-I signals

Hyperglycemia is an essential risk factor for mothers and fetuses in gestational diabetes. Clinical observation has indicated that the offspring of mothers with diabetes shows impaired somatosensory function and IQ. However, only a few studies have explored the effects of hyperglycemia on fetal brain development. Neurodevelopment is susceptible to environmental conditions. Thus, this study aims to investigate the effects of maternal hyperglycemia on fetal brain development and to evaluate insulin and insulin-like growth factor-I (IGF-I) signals in fetal brain under hyperglycemia or controlled hyperglycemia. At day 1 of pregnancy, gestational rats were intraperitoneally injected with streptozocin (60 mg/kg). Some of the hyperglycemic gestational rats were injected with insulin (20 IU, two times a day) to control hyperglycemia; the others were injected with saline of equal volume. The gestational rats were sacrificed at days 14, 16, and 18 of embryo development. The dendritic spines of subplate cortex neurons in the fetal brain were detected by Golgi-Cox staining. The mRNA levels of insulin receptors (IRs) and IGF-IR in the fetal brain were measured using qRT-PCR. The protein levels of synaptophysin, IR, and IGF-IR in the fetal brain were detected by western blot. No significant difference in fetal brain formation was observed between the maternal hyperglycemic group and insulin-treated group. By contrast, obvious retardation of dendritic development in the fetus was observed in the maternal hyperglycemic group. Similarly, synaptophysin expression was lower in the fetus of the maternal hyperglycemic group than in that of the insulin-treated group. The mRNA and protein expression levels of IRs in the fetal brain were higher in the hyperglycemic group than in the insulin-treated group. By contrast, the levels of IGF-IR in the brain were lower in the fetus of the maternal hyperglycemic group than in that of the insulin-treated group. These results suggested that maternal hyperglycemia can retard dendritic development in the fetal brain and that these changes partially resulted from abnormal insulin/IGF-I signaling in the fetal brain.

Evaluation of oral glucose tolerance test, β-cell function and adverse obstetric outcomes

This study was conducted in order to investigate the prevalence of impaired glucose tolerance (IGT) and gestational diabetes mellitus (GDM), their effect on pregnancy and their association with adverse obstetric outcomes. A cross-sectional study was performed on 345 pregnant women, who were screened between the 24th and 28th gestational week with a 75-g oral glucose tolerance test following abnormal results at 1 h after a 50-g oral glucose challenge test. The obstetric outcomes were recorded along with plasma glucose and insulin levels, homeostasis model assessment of insulin resistance (HOMA-IR) and homeostasis model assessment of β-cell function index (HOMA-βCFI) and 50 subjects were excluded due to incomplete data recovery. Of the 295 pregnant women, 18.6% (55/295) were diagnosed with GDM and 32% (95/295) with IGT. The GDM group exhibited significantly higher fasting and 1-h blood glucose concentrations compared to the normal glucose tolerance (NGT) and IGT groups (P<0.01). The 2- and 3-h insulin values of the NGT group were significantly lower compared to those of the GDM group (P<0.05, P<0.01). In the IGT group, the 2-h insulin values were higher compared to the NGT group and the 3-h values were significantly higher (P<0.01), similar to the GDM group. There was a tendency for progressively decreased β-cell function and increased HOMA-IR from the NGT to the IGT to the GDM group. The adverse outcomes of pregnancy-induced hypertension, fetal distress, neonatal hyperbilirubinemia, preterm delivery, macrosomia and cesarean delivery indicated an association with HOMA-βCFI and HOMA-IR. In conclusion, these findings suggest a clinical significance of β-cell dysfunction in women with gestational IGT.

To evaluate the prevalence and clinical outcomes using a one-step method versus a two-step method to screen gestational diabetes mellitus

OBJECTIVE

The goal of this study is to compare the prevalence and clinical outcomes of a one-step with a two-step screening method, both of which are commonly used for the diagnosis of gestational diabetes mellitus (GDM).

METHODS

Women who presented for GDM screening and who consented to participate in this study were randomized into two groups. The women in Group 1 (n = 386) were screened using a one-step method (2-h, 75 g oral glucose tolerance test (OGTT)) and in Group 2 (n = 400) by a two-step method (the 50 g glucose challenge test (GCT) followed by the 100 g OGTT). The pregnancies were then classified into three subgroups as follows: women who had negative 2-h 75 g OGTT results according to IADPSG criteria (IADPSG-negative), women with negative 50 g GCT results (GCT-negative) and women with positive 50 g GCT results but negative 3-h 100 g OGTT results according to C&C criteria (C&C-negative).

RESULTS

The prevalence of GDM using the one-step and two-step methods was 14.5% and 6%, respectively. In adjusted multivariable regression models, women in the GCT-negative and the C&C-negative groups had greater risk of polyhydramnios than women in the IADPSG-negative group [adjusted prevalence risk ratios (aPR), 1.40; 95% confidence intervals (CI), 1.03-1.91; aPR, 2.76; 95% CI, 1.27-6.02, respectively]. Women in the C&C-negative group had greater risk of pre-eclampsia than women in the IADPSG-negative group (aPR, 3.30; 95% CI, 1.57-6.91).

CONCLUSIONS

Women who were defined as having normal glucose tolerance by IADPSG had better perinatal outcomes than women who were defined as having normal glucose tolerance by GCT and women who were GCT-positive with a negative OGTT.

Diabetes in pregnancy among indigenous women in Australia, Canada, New Zealand and the United States

Recently proposed international guidelines for screening for gestational diabetes mellitus (GDM) recommend additional screening in early pregnancy for sub-populations at a high risk of type 2 diabetes mellitus (T2DM), such as indigenous women. However, there are criteria that should be met to ensure the benefits outweigh the risks of population-based screening. This review examines the published evidence for early screening for indigenous women as related to these criteria. Any publications were included that referred to diabetes in pregnancy among indigenous women in Australia, Canada, New Zealand and the United States (n = 145). The risk of bias was appraised. There is sufficient evidence describing the epidemiology of diabetes in pregnancy, demonstrating that it imposes a significant disease burden on indigenous women and their infants at birth and across the lifecourse (n = 120 studies). Women with pre-existing T2DM have a higher risk than women who develop GDM during pregnancy. However, there was insufficient evidence to address the remaining five criteria, including the following: understanding current screening practice and rates (n = 7); acceptability of GDM screening (n = 0); efficacy and cost of screening for GDM (n = 3); availability of effective treatment after diagnosis (n = 6); and effective systems for follow-up after pregnancy (n = 5). Given the impact of diabetes in pregnancy, particularly undiagnosed T2DM, GDM screening in early pregnancy offers potential benefits for indigenous women. However, researchers, policy makers and clinicians must work together with communities to develop effective strategies for implementation and minimizing the potential risks. Evidence of effective strategies for primary prevention, GDM treatment and follow-up after pregnancy are urgently needed.

The diagnostic criteria for gestational diabetes: to change or not to change?

The different screening and diagnostic methods for gestational diabetes mellitus (GDM) currently in clinical use have led the National Institutes of Health Office of Disease Prevention to organize a consensus conference to better understand the potential ramifications of changing the current screening and diagnostic criteria in the United States vs keeping current practices in place. Research has demonstrated that even mild forms of hyperglycemia potentially pose significant adverse health consequences for pregnant women and their children. Thus, it is anticipated that lowering the diagnostic criteria for GDM will significantly reduce morbidity and health care costs in the long term. However, such a change would dramatically increase the number of women identified as having this disease and place a significantly greater burden on an already overburdened primary health care system. Although several cost-benefit analyses suggest that such a change will improve health outcomes for mothers and babies, at least 1 study found that these anticipated public health benefits will not occur unless a higher level of care is devoted to these newly diagnosed patients. There also is a distinct possibility that changing the diagnostic criteria for GDM will increase cesarean delivery rates, which might offset many of the public health gains engendered by diagnosing more women with this condition. The scientific dilemma to change or not to change, thus, requires a rigorous analysis of the scientific, economic, practice, and legal pros and cons to achieve a satisfactory answer.

Circadian variation in the response to the glucose challenge test in pregnancy: implications for screening for gestational diabetes mellitus

OBJECTIVE

A common approach to screening for gestational diabetes mellitus (GDM) is the universal testing of all pregnant women with a 1-h, 50-g glucose challenge test (GCT), followed by a diagnostic oral glucose tolerance test (OGTT) in those in whom the GCT is positive (≥7.8 mmol/L). More important, the GCT is performed at any time of day, but there has been limited study of the effect of time of day on test performance. Thus, using their subsequent OGTT (performed in the morning), we sought to characterize the metabolic function of women with positive GCTs in relation to the timing of their test.

RESEARCH DESIGN AND METHODS

A total of 927 women with positive GCTs underwent a 3-h 100-g OGTT. They were stratified into four groups by time of day (hours) of their GCT: <0900 (n = 171), 0900-1059 (n = 288), 1100-1259 (n = 189), and ≥1300 (n = 279).

RESULTS

On the OGTT, the prevalence of GDM progressively decreased across the GCT groups from <0900 h (26.9%) to 0900-1059 h (25.0%) to 1100-1259 h (21.7%) to ≥1300 h (21.5%; P = 0.0022). After adjustment for GDM risk factors, mean adjusted glucose area under the curve (AUC(gluc)) similarly decreased across the groups, while insulin sensitivity (Matsuda index) and β-cell function (Insulin Secretion-Sensitivity Index-2) progressively increased (all P < 0.0001). In particular, compared with the <0900- and 0900-1059-h groups, women whose positive GCT occurred after 1300 h had superior metabolic function, as evidenced by lower AUC(gluc), higher insulin sensitivity, and better β-cell function (all P ≤ 0.0097).

CONCLUSIONS

Among women with a positive GCT, those tested in the afternoon have better metabolic function and a lower risk of GDM on subsequent OGTT.