The postprandial glucose profile in the diabetic pregnancy

Effectiveness of remote monitoring for glycemic control on maternal-fetal outcomes in women with gestational diabetes mellitus: A meta-analysis

BACKGROUND

The current pandemic and future public health emergencies highlight the importance of evaluating a telehealth care model. Previous studies have reached mixed conclusions about the effectiveness of remote monitoring on glycemic control and maternal and infant outcomes in women with gestational diabetes mellitus (GDM).

OBJECTIVES

This meta-analysis aimed to evaluate the effectiveness of remote blood glucose monitoring for women with gestational diabetes mellitus and to provide evidence-based guidance on the management of women with gestational diabetes mellitus for policymakers and healthcare providers during situations such as pandemics or natural disasters.

METHODS

The Cochrane Library, PubMed, Web of Science, EBSCO, Embase, Medline, CINAHL databases, and ClinicalTrials.gov were systematically searched from their inception to July 10, 2021. Randomized controlled trials (RCTs) published in English with respect to remote blood glucose monitoring in women with GDM were included in the meta-analysis. Two independent reviewers performed data extraction and assessed the quality of the studies. Risk ratios, mean differences, 95% confidence intervals, and heterogeneity were calculated.

RESULTS

A total of 1265 participants were included in the 11 RCTs. There were no significant differences in glycemic control and maternal-fetal outcomes between the remote monitoring group and a standard care group, which included glycosylated hemoglobin (HbA1c), fasting blood glucose, mean 2-h postprandial blood glucose, caesarean birth, gestational weight gain, shoulder dystocia, neonatal hypoglycemia, and other outcomes.

CONCLUSION

This meta-analysis reveals that it is unclear if remote glucose monitoring is preferable to standard of care glucose monitoring. To improve glycemic control and maternal-fetal outcomes during the current epidemic or other natural disasters, the implementation of double-blind RCTs in the context of simulating similar disasters remains to be studied in the future.

The effect of oral probiotics on glycemic control of women with gestational diabetes mellitus-a multicenter, randomized, double-blind, placebo-controlled trial

BACKGROUND

Gestational diabetes mellitus should be treated adequately to avoid maternal hyperglycemia-related complications. Previously, probiotic supplements were suggested to improve fasting blood glucose in women with gestational diabetes mellitus. However, a major limitation of previous studies was that preprandial and especially postprandial glucose values, which are important predictors of pregnancy outcomes, were not studied.

OBJECTIVE

This study aimed to examine the effect of a mixture of probiotic strains on maternal glycemic parameters, particularly preprandial and postprandial glucose values and pregnancy outcomes among women with gestational diabetes mellitus.

STUDY DESIGN

A multicenter prospective randomized, double-blind, placebo-controlled trial was conducted. Women newly diagnosed with gestational diabetes mellitus were randomly allocated into a research group, receiving 2 capsules of oral probiotic formula containing Bifidobacterium bifidum, B lactis, Lactobacillus acidophilus, L paracasei, L rhamnosus, and Streptococcus thermophilus (>6 × 109/capsule), and a control group, receiving a placebo (2 capsules/day) until delivery. Glycemic control was evaluated by daily glucose charts. After 2 weeks, pharmacotherapy was started in case of poor glycemic control. The primary outcomes were the rate of women requiring medications for glycemic control and mean daily glucose charts after 2 weeks of treatment with the study products.

RESULTS

Forty-one and 44 women were analyzed in the treatment and placebo cohorts, respectively. Mean daily glucose during the first 2 weeks in the probiotics and placebo groups was 99.7±7.9 and 98.0±9.3 mg/dL, respectively (P=.35). The rate of women needing pharmacotherapy because of poor glycemic control after 2 weeks of treatment in the probiotics and placebo groups was 24 (59%) and 18 (41%), respectively (P=.10). Mean preprandial and postprandial glucose levels throughout the study period were similar between the groups (P>.05). There were no differences in maternal and neonatal outcomes, including birthweight and adverse effect profile between the groups.

CONCLUSION

The oral probiotic product tested in this study did not affect glycemic control of women with gestational diabetes mellitus.

Various screening and diagnosis approaches for gestational diabetes mellitus and adverse pregnancy outcomes: a secondary analysis of a randomized non-inferiority field trial

INTRODUCTION

We evaluate which screening and diagnostic approach resulted in the greatest reduction in adverse pregnancy outcomes due to increased treatment.

RESEARCH DESIGN AND METHODS

This study presents a secondary analysis of a randomized community non-inferiority trial conducted among pregnant women participating in the GULF Study in Iran. A total of 35 430 pregnant women were randomly assigned to one of the five prespecified gestational diabetes mellitus (GDM) screening protocols. The screening methods included fasting plasma glucose (FPG) in the first trimester and either a one-step or a two-step screening method in the second trimester of pregnancy. According to the results, participants were classified into 6 groups (1) First-trimester FPG: 100-126 mg/dL, GDM diagnosed at first trimester; (2) First trimester FPG: 92-99.9 mg/dL, GDM diagnosed at first trimester; (3) First trimester FPG: 92-99.9 mg/dL, GDM diagnosed at second trimester; (4) First trimester FPG: 92-99.9 mg/dL, healthy at second trimester; (5) First trimester FPG<92 mg/dL, GDM diagnosed at second trimester; (6) First trimester FPG<92 mg/dL, healthy at second trimester. For our analysis, we initially used group 6, as the reference and repeated the analysis using group 2, as the reference group. The main outcome of the study was major adverse maternal and neonatal outcomes.

RESULTS

Macrosomia and primary caesarean section occurred in 9.8% and 21.0% in group 1, 7.8% and 19.8% in group 2, 5.4% and 18.6% in group 3, 6.6% and 21.5% in group 4, 8.3% and 24.0% in group 5, and 5.4% and 20.0% in group 6, respectively. Compared with group 6 as the reference, there was a significant increase in the adjusted risk of neonatal intensive care unit (NICU) admission in groups 1, 3, and 5 and an increased risk of macrosomia in groups 1, 2, and 5. Compared with group 2 as the reference, there was a significant decrease in the adjusted risk of macrosomia in group 3, a decreased risk of NICU admission in group 6, and an increased risk of hyperglycemia in group 3.

CONCLUSIONS

We conclude that screening approaches for GDM reduced the risk of adverse pregnancy outcomes to the same or near the same risk level of healthy pregnant women, except for the risk of NICU admission that increased significantly in groups diagnosed with GDM compared with healthy pregnant women. Individuals with slight increase in FPG (92-100 mg/dL) at first trimester, who were diagnosed as GDM, had an even increased risk of macrosomia in comparison to those group of women with FPG 92-100 mg/dL in the first trimester, who were not diagnosed with GDM, and developed GDM in second trimester TRIAL REGISTRATION: IRCT138707081281N1 (registered: February 15, 2017).

Efficacy of Postprandial Exercise in Mitigating Glycemic Responses in Overweight Individuals and Individuals with Obesity and Type 2 Diabetes-A Systematic Review and Meta-Analysis

Studies investigating the acute effect of postprandial exercise (PPE) on glucose responses exhibit significant heterogeneity in terms of participant demographic, exercise protocol, and exercise timing post-meal. As such, this study aimed to further analyze the existing literature on the impact of PPE on glycemic control in overweight individuals and individuals with obesity and type 2 diabetes (T2DM). A literature search was conducted through databases such as PubMed, CINAHL, and Google Scholar. Thirty-one original research studies that met the inclusion criteria were selected. A random-effect meta-analysis was performed to compare postprandial glucose area under the curve (AUC) and 24 h mean glucose levels between PPE and the time-matched no-exercise control (CON). Subgroup analyses were conducted to explore whether the glucose-lowering effect of PPE could be influenced by exercise duration, exercise timing post-meal, and the disease status of participants. This study revealed a significantly reduced glucose AUC (Hedges' g = -0.317; SE = 0.057; p < 0.05) and 24 h mean glucose levels (Hedges' g = -0.328; SE = 0.062; p < 0.05) following PPE compared to CON. The reduction in glucose AUC was greater (p < 0.05) following PPE lasting >30 min compared to ≤30 min. The reduction in 24 h mean glucose levels was also greater (p < 0.05) following PPE for ≥60 min compared to <60 min post-meal and in those with T2DM compared to those without T2DM. PPE offers a viable approach for glucose management and can be performed in various forms so long as exercise duration is sufficient. The glucose-lowering effect of PPE may be further enhanced by initiating it after the first hour post-meal. PPE is a promising strategy, particularly for patients with T2DM. This manuscript is registered with Research Registry (UIN: reviewregistry1693).

Comparison of one hour versus 90 minute postprandial glucose measurement in women with gestational diabetes; which one is more effective?

In the present study, we aimed to compare postprandial 90 minute measurements and postprandial 1 hour (PP1-HR) measurements for prediction of foetal growth disturbances and pregnancy complications. This was a prospective study conducted in Acıbadem Mehmet Ali Aydınlar University Altunizade Hospital in Department of Perinatology. The study group consisted of patients diagnosed with gestational diabetes. In each antepartum visit, the patients fasting plasma glucose as well as PP1-HR and 90 minute measurements were made. Perinatal and neonatal data were obtained from each patient. The rate of large for gestational age infants was increased in patients when either PP1-HR measurement above 140 mg/dl or postprandial 90 minute measurement above 165 mg/dl compared to patients with normal PP1-HR or postprandial 90 minute measurement. Preterm delivery rate was increased in patients with postprandial 90 minute measurement above 165 mg/dl but not in patients with PP1-HR measurement above 140 mg/dl. The optimal cut-off for postprandial 90 minute measurement was 165 mg/dl based on receiver operating characteristics curve. Our preliminary data show that postprandial 90 minute measurements are superior to PP1-HR measurements in predicting large for gestational age infants.Impact StatementWhat is already known on this subject? Gestational diabetes (GDM) is defined as any degree of glucose intolerance with onset or first recognition in pregnancy. Maternal hyperglycaemia has been linked to metabolic alterations in the foetus and thus brings about foetal macrosomia as well as other pregnancy complications such as preterm delivery and preeclampsia.What the results of this study add? The findings of the present study suggest that postprandial 90 minute predicted more cases of LGA infants than postprandial 1-hour (PP1-HR) measurements. In addition, the rate of preterm deliveries was found to be increased in patients with mean postprandial 90 minute measurements above 165 mg/dl compared to patients with postprandial 90 minute measurements below 165 mg/dl. However, the rate of preterm deliveries was similar in patients with elevated PP1-HR measurements and patients with normal PP1-HR measurements.What the implications are of these findings for clinical practice and/or further research? Our study is the first to investigate the usefulness of postprandial 90 minute in a prospective design. Our preliminary data show that postprandial 90 minute measurements are superior to PP 1 measurements in predicting LGA babies. It also correlates better with preterm deliveries.

Comparison of postprandial 90th-minute plasma glucose level with 60th- and 120th-minute levels in patients with gestational diabetes: a prospective cohort study

PURPOSE

The objective of the present study is to compare postprandial 90th-minute plasma glucose measurement with fasting, postprandial 60 and 120 min in gestational diabetes mellitus (GDM).

METHODS

One hundred and thirty-one pregnant women with GDM were hospitalized for regulation of maternal plasma glucose levels. Plasma glucose levels were daily recorded for every patient and treatment option arranged without considering the 90th-minute plasma glucose level. All patients were followed up until birth and pregnancy results were compared.

RESULT

At the admission, 69% of our patients were on diet and 31% were on insulin with diet therapy. The highest postprandial mean plasma glucose was seen at 90 min after breakfast (137.50 mg/dl), at 60 min after lunch (137.80 mg/dl), and 60 min after dinner (134.50 mg/dl). The cut-off level for postprandial glucose at 90th minute was determined as 130 mg/dl. The upper limit plasma glucose levels were most frequently exceeded at 90th minute for each meal. High plasma glucose levels and the need for neonatal intensive care unit were correlated (p < 0.05).

CONCLUSIONS

The highest plasma glucose level was seen at 90 min after breakfast, 60 min after lunch, and 60 min after dinner. The upper limit plasma glucose levels were most frequently exceeded at the 90 min.

Pharmacologic Treatment of Diabetes in Pregnancy

Importance

Diabetes affects 6% to 9% of pregnancies, with gestational diabetes mellitus accounting for more than 90% of cases. Pregestational and gestational diabetes are associated with significant maternal and fetal risks; therefore, screening and treatment during pregnancy are recommended. Recommendations regarding the preferred treatment of diabetes in pregnancy have recently changed, with slight differences between American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) recommendations.

Objective

Our review discusses the diagnosis, management, and treatment of pregestational and gestational diabetes with the oral hypoglycemic agents metformin and glyburide as well as insulin. We also review the evidence for the safety and efficacy of these medications in pregnancy.

Evidence Acquisition

Articles were obtained from PubMed, the ACOG Practice Bulletin on Gestational Diabetes Mellitus, and the SMFM statement on the pharmacological treatment of gestational diabetes.

Results

Insulin does not cross the placenta and has an established safety profile in pregnancy and is therefore considered a first-line treatment for gestational diabetes. Metformin and glyburide have also been shown to be relatively safe in pregnancy but with more limited long-term data. Regarding maternal and fetal outcomes, metformin is superior to glyburide and similar to insulin.

Conclusions and Relevance

Insulin is the preferred pharmacologic treatment according to ACOG. However, SMFM has stated that outcomes with metformin are similar, and it may also be considered as first-line therapy. Both agree that the available data show that metformin is safer and superior to glyburide, and glyburide is no longer recommended as a first-line therapy for the treatment of gestational diabetes.

Inverse association between 1,5-anhydroglucitol and neonatal diabetic complications

PURPOSE

A glycemic control marker to predict neonatal diabetic complications is unavailable. We aimed to examine if 1,5-anhydroglucitol (1,5-AG) can predict neonatal complications in women with diabetes in pregnancy.

METHODS

Prospective observational study from December 2011 to August 2013. We recruited 105 women, 70 diabetic (gestational and pregestational) and 35 nondiabetic. 1,5-AG at birth was compared between the two groups. In the diabetic group 1,5-AG, HbA1c, and fructosamine were measured before glycemic control initiation (first visit), after 4-6 weeks (second visit), and at delivery. Women were divided to poor (1,5-AG values below median at birth) and good (1,5-AG values at median and above) glycemic control groups. Mean daily glucose charts were collected. The primary outcome was a composite of neonatal diabetic complications: respiratory distress, hypoglycemia, polycythemia, hyperbilirubinemia, and large for gestational age.

RESULTS

Mean 1,5-AG in the nondiabetic group was similar to that of the diabetic group without the composite outcome and was significantly higher than in the diabetic group with the composite outcome. The rate of the composite outcome was higher in the poor glycemic control group compared with the good glycemic control group (adjusted odds ratio (OR) 3.8 95% CI [1.2-12.3]). Only 1,5-AG was inversely associated with the composite outcome at all time points; the second visit was the only independent risk factor in multivariable logistic regression (OR 0.7 95% CI 0.54-0.91). The rest of the glycemic markers were not associated with neonatal composite outcome.

CONCLUSIONS

1,5-AG is inversely associated with neonatal diabetic complications and is superior to other glycemic markers in predicting those complications.

Application and Utility of Continuous Glucose Monitoring in Pregnancy: A Systematic Review

Background: In the past decade, continuous glucose monitoring (CGM) has been proven to have similar accuracy to self-monitoring of blood glucose (SMBG) and yet provides better therapy optimization and detects trends in glucose values due to higher frequency of testing. Even though the feasibility and utility of CGM has been proven successfully in Type 1 and 2 diabetes, there is a lack of knowledge of its application and effectiveness in pregnancy, especially in gestational diabetes mellitus (GDM). In this review, we aimed to summarize and evaluate the updated scientific evidence on the application of CGM in pregnancies complicated with GDM. Methods: A search using keywords related to CGM and GDM on PubMed was conducted and articles were filtered based on full text, year of publication (Jan 1998-Dec 2018), human subject studies, and written in English. Reviews and duplicate articles were removed. A final total of 29 articles were included in this review. Results: In terms of maternal and fetal outcomes, inconsistent evidence was reported. Among GDM patients using CGM and SMBG, two randomized controlled trials (RCTs) found no significant differences in macrosomia, birth weight (BW), and gestational age (GA) at delivery between these two groups, while one prospective cohort found a lower incidence of cesarean section and macrosomia in CGM use subjects. Furthermore, CGM use was consistently found to have increased detection in dysglycemia and glycemic variability compared to SMBG. In terms of clinical utility, CGM use led to more treatment adjustments and lower gestational weight gain (GWG). Lastly, CGM use showed higher postprandial glucose levels in GDM-complicated pregnancies than in normal pregnancies. Conclusion: Current updated evidence suggests that CGM is superior to SMBG among GDM pregnancies in terms of detecting hypoglycemic and hyperglycemic episodes, which might result in an improvement of maternal and fetal outcomes. In addition, CGM detects a wider glycemic variability in GDM mothers than non-GDM controls. Further research with larger sample sizes and complete pregnancy coverage is needed to explore the clinical utility such as screening and predictive values of CGM for GDM.

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.

Glucose Targets and Insulin Choice in Pregnancy: What Has Changed in the Last Decade?

PURPOSE OF REVIEW

To review current glycaemic targets and the potential use of newer insulin formulations in pregnancy.

RECENT FINDINGS

The impact of stricter glycaemic control on perinatal outcomes remains controversial, showing conflicting results. Current ongoing randomised trials investigating the role of tighter glucose targets in pregnancy should help clarify the benefit of tighter glucose control. Optimal timing for self-monitoring blood glucose (SMBG) remains debatable. Data suggest that post-prandial SMBG, particularly at 1 h, offers the best prediction of adverse perinatal outcome. To achieve these targets, insulin is the standard therapy. Novel insulin formulations offer benefits outside of pregnancy. Recent data on the use of new insulins in pregnancy (e.g. insulin degludec and glargine (U 300)) is limited to case reports. Glycaemic targets have remained unchanged in the last decade. Studies using stricter glycaemic targets may improve perinatal outcomes. Newer insulin formulations may offer increased flexibility and glycaemic control. Clinicians caring for women with diabetes striving to minimise adverse perinatal outcomes will find this review of interest.

Evaluating maternal hyperglycemic exposure and fetal placental arterial dysfunction in a dual cotyledon, dual perfusion model

BACKGROUND

Gestational diabetes affects almost 1 in 10 pregnancies and is associated with adverse outcomes including fetal demise. Pregnancy complications related to diabetes are attributed to placental vascular dysfunction. With diabetes, maternal hyperglycemia is thought to promote placental vasoconstriction. However, it remains poorly understood if and how hyperglycemia leads to placental vascular dysfunction or if humoral factors related to maternal diabetes are responsible.

METHODS AND RESULTS

Utilizing a human placenta dual cotyledon, dual perfusion assay we examined the arterial pressure response to the thromboxane mimetic U44619, in cotyledons exposed to normal vs. a hyperglycemic infusion into the intervillous space. Tissues were then analyzed for the activity of key signaling molecules related to vascular tone; eNOS, Akt, PKA and VEGFR2. Results indicate a significant increase in fetal vascular resistance with maternal exposure to hyperglycemia. This response corresponded with a reduction in the phosphorylation of eNOS at Ser1177 and Akt at Thr308. In contrast, VEGFR2 at Tyr1175 and PKA at Thr197 were not different with hyperglycemia.

CONCLUSION

Reductions of eNOS and Akt phosphorylation at key residues implicated in nitric oxide production suggest that hyperglycemia alters the vasodilatory signaling of placental vessels. In contrast, acute hyperglycemic exposure may not alter vasoconstriction via VEGF and PKA signaling. Altogether our results link hyperglycemic exposure in human placentas to nitric oxide signaling; a mechanisms that may account for the elevations in vascular resistance commonly observed in diabetic pregnancies.

Glucose Profiles in Pregnant Women After a Gastric Bypass : Findings from Continuous Glucose Monitoring

BACKGROUND

The diagnosis of gestational diabetes mellitus (GDM) usually requires an oral glucose tolerance test, but this procedure seems inappropriate after gastric bypass surgery (Roux-en-Y gastric bypass (RYGB)) due to specific altered glycemic responses. We aimed here at describing continuous glucose monitoring (CGM) profile of pregnant women after RYGB.

METHODS

CGM was performed in 35 consecutive pregnant women after RYGB at 26.2 ± 5 weeks of gestation.

RESULTS

After RYGB, pregnant women display high postprandial interstitial glucose (IG) peaks and low IG before and 2 h after meals. The postprandial IG peak is reached early, within 54 ± 9 min. The maximum IG values reach 205 mg/dl, and the percentage of time above 140 mg/dl (6.6 ± 7 %) is similar to what is described in GDM women.

CONCLUSIONS

This study is the first to describe CGM profile in pregnant women after RYGB. CGM features are similar to those of non-pregnant post-RYGB patients, characterized by wide and rapid changes in postprandial IG, and high exposure to hyperglycemia. The exposure to hyperglycemia is similar to what is reported in GDM although the time to postprandial peak is shorter. CGM could be an additional useful approach to screen for glucose intolerance during pregnancy after RYGB.

Different methods and settings for glucose monitoring for gestational diabetes during pregnancy

BACKGROUND

Incidence of gestational diabetes mellitus (GDM) is increasing worldwide. Blood glucose monitoring plays a crucial part in maintaining glycaemic control in women with GDM and is generally recommended by healthcare professionals. There are several different methods for monitoring blood glucose which can be carried out in different settings (e.g. at home versus in hospital).

OBJECTIVES

The objective of this review is to compare the effects of different methods and settings for glucose monitoring for women with GDM on maternal and fetal, neonatal, child and adult outcomes, and use and costs of health care.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (30 September 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-randomised controlled trials (qRCTs) comparing different methods (such as timings and frequencies) or settings, or both, for blood glucose monitoring for women with GDM.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study eligibility, risk of bias, and extracted data. Data were checked for accuracy.We assessed the quality of the evidence for the main comparisons using GRADE, for:- primary outcomes for mothers: that is, hypertensive disorders of pregnancy; caesarean section; type 2 diabetes; and- primary outcomes for children: that is, large-for-gestational age; perinatal mortality; death or serious morbidity composite; childhood/adulthood neurosensory disability;- secondary outcomes for mothers: that is, induction of labour; perineal trauma; postnatal depression; postnatal weight retention or return to pre-pregnancy weight; and- secondary outcomes for children: that is, neonatal hypoglycaemia; childhood/adulthood adiposity; childhood/adulthood type 2 diabetes.

MAIN RESULTS

We included 11 RCTs (10 RCTs; one qRCT) that randomised 1272 women with GDM in upper-middle or high-income countries; we considered these to be at a moderate to high risk of bias. We assessed the RCTs under five comparisons. For outcomes assessed using GRADE, we downgraded for study design limitations, imprecision and inconsistency. Three trials received some support from commercial partners who provided glucose meters or financial support, or both. Main comparisons Telemedicine versus standard care for glucose monitoring (five RCTs): we observed no clear differences between the telemedicine and standard care groups for the mother, for:- pre-eclampsia or pregnancy-induced hypertension (risk ratio (RR) 1.49, 95% confidence interval (CI) 0.69 to 3.20; 275 participants; four RCTs; very low quality evidence);- caesarean section (average RR 1.05, 95% CI 0.72 to 1.53; 478 participants; 5 RCTs; very low quality evidence); and- induction of labour (RR 1.06, 95% CI 0.63 to 1.77; 47 participants; 1 RCT; very low quality evidence);or for the child, for:- large-for-gestational age (RR 1.41, 95% CI 0.76 to 2.64; 228 participants; 3 RCTs; very low quality evidence);- death or serious morbidity composite (RR 1.06, 95% CI 0.68 to 1.66; 57 participants; 1 RCT; very low quality evidence); and- neonatal hypoglycaemia (RR 1.14, 95% CI 0.48 to 2.72; 198 participants; 3 RCTs; very low quality evidence).There were no perinatal deaths in two RCTs (131 participants; very low quality evidence). Self-monitoring versus periodic glucose monitoring (two RCTs): we observed no clear differences between the self-monitoring and periodic glucose monitoring groups for the mother, for:- pre-eclampsia (RR 0.17, 95% CI 0.01 to 3.49; 58 participants; 1 RCT; very low quality evidence); and- caesarean section (average RR 1.18, 95% CI 0.61 to 2.27; 400 participants; 2 RCTs; low quality evidence);or for the child, for:- perinatal mortality (RR 1.54, 95% CI 0.21 to 11.24; 400 participants; 2 RCTs; very low quality evidence);- large-for-gestational age (RR 0.82, 95% CI 0.50 to 1.37; 400 participants; 2 RCTs; low quality evidence); and- neonatal hypoglycaemia (RR 0.64, 95% CI 0.39 to 1.06; 391 participants; 2 RCTs; low quality evidence). Continuous glucose monitoring system (CGMS) versus self-monitoring of glucose (two RCTs): we observed no clear differences between the CGMS and self-monitoring groups for the mother, for:- caesarean section (RR 0.91, 95% CI 0.68 to 1.20; 179 participants; 2 RCTs; very low quality evidence);or for the child, for:- large-for-gestational age (RR 0.67, 95% CI 0.43 to 1.05; 106 participants; 1 RCT; very low quality evidence) and- neonatal hypoglycaemia (RR 0.79, 95% CI 0.35 to 1.78; 179 participants; 2 RCTs; very low quality evidence).There were no perinatal deaths in the two RCTs (179 participants; very low quality evidence). Other comparisons Modem versus telephone transmission for glucose monitoring (one RCT): none of the review's primary outcomes were reported in this trial Postprandial versus preprandial glucose monitoring (one RCT): we observed no clear differences between the postprandial and preprandial glucose monitoring groups for the mother, for:- pre-eclampsia (RR 1.00, 95% CI 0.15 to 6.68; 66 participants; 1 RCT);- caesarean section (RR 0.62, 95% CI 0.29 to 1.29; 66 participants; 1 RCT); and- perineal trauma (RR 0.38, 95% CI 0.11 to 1.29; 66 participants; 1 RCT);or for the child, for:- neonatal hypoglycaemia (RR 0.14, 95% CI 0.02 to 1.10; 66 participants; 1 RCT).There were fewer large-for-gestational-age infants born to mothers in the postprandial compared with the preprandial glucose monitoring group (RR 0.29, 95% CI 0.11 to 0.78; 66 participants; 1 RCT).

AUTHORS' CONCLUSIONS

Evidence from 11 RCTs assessing different methods or settings for glucose monitoring for GDM suggests no clear differences for the primary outcomes or other secondary outcomes assessed in this review.However, current evidence is limited by the small number of RCTs for the comparisons assessed, small sample sizes, and the variable methodological quality of the RCTs. More evidence is needed to assess the effects of different methods and settings for glucose monitoring for GDM on outcomes for mothers and their children, including use and costs of health care. Future RCTs may consider collecting and reporting on the standard outcomes suggested in this review.

CGM, Pregnancy, and Remote Monitoring

The glycemic goals of pregnancy are very narrow to reduce excess risks for numerous maternal and fetal complications. Continuous glucose monitors (CGMs) may help women achieve glucose goals and reduce hypoglycemia. CGM use has been found to be safe and effective in pregnancies associated with diabetes. CGM use can accurately identify glycemic patterns among women with and without diabetes in pregnancy. The data on the effects of CGM use on maternal and fetal outcomes are conflicting. Using CGMs in conjunction with continuous subcutaneous insulin infusion therapy in pregnancies complicated by diabetes may improve outcomes. There are limitations of CGM use that affect patients in and outside of pregnancy, as well as specific barriers that only affect pregnant women. Of importance, CGM use does not replace standard clinical care, but may be used an adjunctive tool in pregnancy. CGM remote monitoring in pregnancy is an understudied field. In this study, we review the studies on CGM use in pregnancy.

Glyburide Versus Metformin and Their Combination for the Treatment of Gestational Diabetes Mellitus: A Randomized Controlled Study

OBJECTIVE

To compare the efficacy and safety of glyburide versus metformin and their combination for the treatment of gestational diabetes mellitus (GDM).

RESEARCH DESIGN AND METHODS

In this prospective randomized controlled study, we randomly assigned patients with GDM at 13-33 weeks gestation and whose blood glucose was poorly controlled by diet to receive either glyburide or metformin. If optimal glycemic control was not achieved, the other drug was added. If adverse effects occurred, the drug was replaced. If both failed, insulin was given. The primary outcomes were the rate of treatment failure and glycemic control after the first-line medication according to mean daily glucose charts.

RESULTS

Glyburide was started in 53 patients and metformin in 51. In the glyburide group, the drug failed in 18 (34%) patients due to adverse effects (hypoglycemia) in 6 (11%) and lack of glycemic control in 12 (23%). In the metformin group, the drug failed in 15 (29%) patients, due to adverse effects (gastrointestinal) in 1 (2%) and lack of glycemic control in 14 (28%). Treatment success after second-line therapy was higher in the metformin group than in the glyburide group (13 of 15 [87%] vs. 9 of 18 [50%], respectively; P = 0.03). In the glyburide group, nine (17%) patients were eventually treated with insulin compared with two (4%) in the metformin group (P = 0.03). The combination of the drugs reduced the need for insulin from 33 (32%) to 11 (11%) patients (P = 0.0002). Mean daily blood glucose and other obstetrical and neonatal outcomes were comparable between groups, including macrosomia, neonatal hypoglycemia, and electrolyte imbalance.

CONCLUSIONS

Glyburide and metformin are comparable oral treatments for GDM regarding glucose control and adverse effects. Their combination demonstrates a high efficacy rate with a significantly reduced need for insulin, with a possible advantage for metformin over glyburide as first-line therapy.

One-hour versus two-hour postprandial blood glucose measurement in women with gestational diabetes mellitus: which is more predictive?

The purpose of this study is to investigate postprandial 1-h (PP1) and 2-h (PP2) blood glucose measurements' correlation with adverse perinatal outcomes. This prospective cohort study consisted of 259 women with gestational diabetes mellitus. During each antenatal visit, HbA1c and fasting plasma glucose (FPG) as well as plasma glucose at PP1 and PP2 were analyzed. There were 144 patients on insulin therapy and 115 patients on diet therapy. A total of 531 blood glucose measurements were obtained at different gestational ages between 24 and 41 gestational weeks. PP2 plasma glucose measurements (but not PP1) were positively correlated with fetal macrosomia. But on adjusted analysis, neither PP1 nor PP2 measurements predicted perinatal complications. In addition to PP1 and PP2, neither FPG nor HbA1c were able to predict perinatal complications or fetal macrosomia when controlled for confounding factors except for a positive correlation between fetal macrosomia and HbA1c in patients on diet therapy. Postprandial 1-h and postprandial 2-h plasma glucose measurements were not superior to each other in predicting fetal macrosomia or perinatal complications. Based on our findings, it can be concluded that both methods may be suitable for follow-up as there are no clear advantages of one measurement over the other.

Continuous Glucose Monitoring in Patients with Abnormal Glucose Tolerance during Pregnancy: A Case Series

Abnormal glucose tolerance during pregnancy is associated with perinatal complications. We used continuous glucose monitoring (CGM) in pregnant women with glucose intolerance to achieve better glycemic control and to evaluate the maternal glucose fluctuations. We also used CGM in women without glucose intolerance (the control cases). Furthermore, the standard deviation (SD) and mean amplitude of glycemic excursions (MAGE) were calculated for each case. For the control cases, the glucose levels were tightly controlled within a very narrow range; however, the SD and MAGE values in pregnant women with glucose intolerance were relativity high, suggesting postprandial hyperglycemia. Our results demonstrate that pregnant women with glucose intolerance exhibited greater glucose fluctuations compared with the control cases. The use of CGM may help to improve our understanding of glycemic patterns and may have beneficial effects on perinatal glycemic control, such as the detection of postprandial hyperglycemia in pregnant women.

Glycemic targets in pregnancies affected by diabetes: historical perspective and future directions

The definition of optimal glycemic control in pregnancies affected by diabetes remains enigmatic. Diabetes phenotypes are heterogeneous. Moreover, fetal macrosomia insidiously occurs even with excellent glycemic control. Current blood glucose (BG) targets (FBG ≤95, 1-h post-prandial <140, 2 h <120 mg/dL) have improved perinatal outcomes, but arguably they have not normalized. The conventional management approach has been to replicate a pattern of glycemia in normal pregnancy. Although these patterns are lower than previously appreciated, a randomized controlled trial (RCT) has never compared current vs. lower glucose targets powered on maternal/fetal outcomes. This paper provides historical context to the current targets by reviewing evidence supporting their evolution. Using lower targets (FBG <90, 1 h <122, 2 h <110, mean BG ≤95 mg/dL) may help normalize outcomes, but phenotypic differences (type 1 vs. type 2 vs. gestational diabetes) might require different glycemic goals. There remains a critical need for well-designed RCTs to confirm optimal glycemic control that minimizes both small for and large for gestational age across pregnancies affected by diabetes.

The efficacy and effectiveness of continuous glucose monitoring during pregnancy: a systematic review

OBJECTIVE

Diabetic pregnancies carry a high risk for both mother and child, especially when glycemic control is poor. A novel technique that aims to improve glycemic control is the continuous glucose monitor (CGM). This tool is already in use to improve pregnancy outcome. This review presents the available evidence on the efficacy of CGM use in pregnancy and the effectiveness on pregnancy outcome.

METHODS

A systematic search was conducted using PubMed, EMBASE, and the Cochrane Libraries for articles on CGM in pregnancy. We evaluated the selected articles with particular attention for clinical and cost-effectiveness of CGM to improve pregnancy outcome.

RESULTS

We retrieved 5032 articles, 11 of which remained as relevant after selection according to predefined criteria. Most studies were limited to the evaluation of the role of CGM on clinical decision making. Only 2 studies were randomized controlled trials (RCTs) evaluating the effect on pregnancy outcome. One small RCT on retrospective CGM showed a significant reduction in third-trimester HbA1c and a significant reduction in neonatal macrosomia. A second RCT on real-time CGM did not show any effect on either glycemic control or on pregnancy outcome.

CONCLUSIONS

Current evidence on the efficacy of CGM on improving glycemic control during pregnancy as well as on the effectiveness on pregnancy outcome is limited to 2 RCTs with contradicting results. Evidence on the cost-effectiveness is lacking. Further proper RCTs on the effectiveness and cost-effectiveness of CGM in pregnancy are required before wide implementation in practice.

Intrapartum application of the continuous glucose monitoring system in pregnancies complicated with diabetes: A review and feasibility study

Intrapartum maternal normoglycemia seems to play an important role in the prevention of adverse perinatal, maternal and neonatal outcomes. Several glucose monitoring protocols have been developed, aiming to achieve a tight glucose monitoring and control. Depending on the type of diabetes and the optimal or suboptimal glycemic control, the treatment options include fasting status of the parturient, frequent monitoring of capillary blood glucose, intravenous dextrose infusion and subcutaneous or intravenous use of insulin. Continuous glucose monitoring system (CGMS) is a relatively new technology that measures interstitial glucose at very short time intervals over a specific period of time. The resulting profile provides a more comprehensive measure of glycemic excursions than intermittent home blood glucose monitoring. Results of studies applying the CGMS technology in patients with or without diabetes mellitus (DM) have revealed new insights in glucose metabolism. Moreover, CGMS have a potential role in the improvement of glycemic control during pregnancy and labor, which may lead to a decrease in perinatal morbidity and mortality. In conclusion, the use of CGMS, with its important technical advantages compared to the conventional way of monitoring, may lead into a more etiological intrapartum management of both the mother and her fetus/infant in pregnancies complicated with DM.

A standard approach to continuous glucose monitor data in pregnancy for the study of fetal growth and infant outcomes

The power of continuous glucose monitoring system (CGMS) technology to profile glycemic patterns throughout a 24-h period has benefited the care of individuals with diabetes mellitus for over 10 years. Recently, this technology has been utilized to better understand glucose patterns in pregnancy, especially as they relate to abnormal fetal growth given that adiposity at birth is associated with increased risks for childhood obesity and metabolic syndrome. However, the lack of a standardized approach to defining glucose measures associated with maternal outcomes and fetal growth has greatly limited comparison and pooling of CGMS data among pregnancy trials, hindering our ability to take advantage of the enormous amount of data available to explore these relationships. The purpose of this article is to offer a methodical approach to the identification and extraction of CGMS-derived glucose variables for the characterization of glycemic profiles in pregnant women, particularly focusing on women with gestational diabetes or obesity who are at risk for abnormal fetal growth. A review of the properties of CGMS data and examples of how CGMS data in pregnancy have been reported to date are included. We further define several pregnancy-relevant, CGMS-derived glucose variables and directly apply them to unpublished data to illustrate how these measures might be utilized. This approach offers one possible standardized method to define and analyze these time-sensitive glucose measures to facilitate comparisons among studies and to increase our understanding of how glycemic profiles contribute to excess infant adiposity in pregnant women with and without diabetes.

Role of continuous glucose monitoring in the management of diabetic pregnancy

Self-monitoring of blood glucose (SMBG) with intermittent capillary glucose fingerstick tests is currently the universally accepted method of glucose monitoring in pregnancy. During pregnancy SMBG tests are recommended before and after meals and before bed (typically 7 values/d). Continuous glucose monitoring systems consist of a disposable subcutaneous glucose-sensing device, electrochemically measuring glucose levels in subcutaneous tissues every 10 seconds, providing an average interstitial glucose value every 5 minutes (typically 288 values/d). From a research perspective this provides unprecedented insights into the pathophysiology of glucose metabolism, while from a clinical perspective it can facilitate enhanced patient-professional decision making, patient motivation, and improved glycaemic control. CGM has thus been described as a "roadmap for effective self-management" and as a "stepping stone in the journey towards a cure." This review will consider the lessons learned and evidence supporting current and potential future use of CGM in the management of diabetes in pregnancy.

Timing of peak blood glucose after breakfast meals of different glycemic index in women with gestational diabetes

This study aims to determine the peak timing of postprandial blood glucose level (PBGL) of two breakfasts with different glycemic index (GI) in gestational diabetes mellitus (GDM). Ten women with diet-controlled GDM who were between 30 and 32 weeks of gestation were enrolled in the study. They consumed two carbohydrate controlled, macronutrient matched bread-based breakfasts with different GI (low vs. high) on two separate occasions in a random order after an overnight fast. PBGLs were assessed using a portable blood analyser. Subjects were asked to indicate their satiety rating at each blood sample collection. Overall the consumption of a high GI breakfast resulted in a greater rise in PBGL (mean ± SEM peak PBGL: low GI 6.7 ± 0.3 mmol/L vs. high GI 8.6 ± 0.3 mmol/L; p < 0.001) and an earlier peak PBGL time (16.9 ± 4.9 min earlier; p = 0.015), with high variability in PBGL time between subjects. There was no significant difference in subjective satiety throughout the test period. In conclusion, the low GI breakfast produced lower postprandial glycemia, and the peak PBGL occurred closer to the time recommended for PBGL monitoring (i.e., 1 h postprandial) in GDM than a macronutrient matched high GI breakfast.

Continuous glucose monitoring in pregnancy: new frontiers in clinical applications and research

Current treatment of diabetes in pregnancy relies on intermittent self-monitoring of blood glucoses using finger sticks to monitor capillary blood glucoses. Continuous glucose monitoring (CGM) systems are an emerging technology that allow frequent glucose measurements (every 5 min) and the ability to monitor glucose trends in real time. Although these devices are currently expensive and mildly invasive to use, there is huge potential for their use in both the research and clinical realms. From a research perspective, there is the potential to better understand glucose metabolism in pregnancy, both in patients with and without diabetes. For the treating clinician, CGM has the potential to improve detection of hyperglycemic excursions as well as asymptomatic hypoglycemia and the data to improve management of glucose levels in diabetes patients. In this article, we review current literature examining use of CGM in both research and clinical applications.

Diagnosis and treatment of hyperglycemia in pregnancy

Hyperglycemia in pregnancy is an opportunity for women at risk for complications during pregnancy and beyond to change their life course to improve outcomes for themselves and their offspring. Providers of diabetes care during pregnancy complicated by hyperglycemia in pregnancy have the unique opportunity to make a significant difference.

Gestational diabetes mellitus: Non-insulin management

Gestational diabetes mellitus (GDM) complicates a substantial number of pregnancies. There is consensus that in patients of GDM, excellent blood glucose control, with diet and, when necessary, oral hypoglycemics and insulin results in improved perinatal outcomes, and appreciably reduces the probability of serious neonatal morbidity compared with routine prenatal care. Goals of metabolic management of a pregnancy complicated with GDM have to balance the needs of a healthy pregnancy with the requirements to control glucose level. Medical nutrition therapy is the cornerstone of therapy for women with GDM. Surveillance with daily self-monitoring of blood glucose has been found to help guide management in a much better way than blood glucose checking in labs and clinics, which tends to be less frequent. Historically, insulin has been the therapeutic agent of choice for controlling hyperglycemia in pregnant women. However, difficulty in medication administration with multiple daily injections, potential for hypoglycemia, and increase in appetite and weight make this therapeutic option cumbersome for many pregnant patients. Use of oral hypogycemic agents (OHAs) in pregnancy has opened new vistas for GDM management. At present, there is a growing acceptance of glyburide (glibenclamide) use as the primary therapy for GDM. Glyburide and metformin have been found to be safe, effective and economical for the treatment of gestational diabetes. Insulin, however, still has an important role to play in GDM. GDM is a window of opportunity, which needs to be seized, for prevention of diabetes in future life. Goal of our educational programs should be not only to improve pregnancy outcomes but also to promote healthy lifestyle changes for the mother that will last long after delivery. Team effort on part of obstetricians and endocrinologists is required to make "the diabetes capital of the world" into "the diabetes care capital of the world".

Factors predicting the need for insulin therapy in patients with gestational diabetes mellitus

AIM

To determine the possible factors predicting the insulin requirement in pregnancies complicated by gestational diabetes mellitus (GDM).

METHOD

A total of 294 patients with GDM diagnosed by the 100-g/3-h oral glucose tolerance test (OGTT) were studied. The following factors were analyzed: maternal age, nulliparity, family history of diabetes, prepregnancy BMI, prior GDM, prior fetal macrosomia, multiple pregnancy, polyhydramnios, gestational age at diagnosis of GDM, smoking, hypertension, number of abnormal 100-g/3-h OGTT values, and glycated hemoglobin (HbA1c). The association between each factor and the need for insulin therapy was then analyzed individually. The performance of these factors to predict the probability of insulin therapy was estimated using a logistic regression model.

RESULTS

Univariate analysis showed a positive correlation between insulin therapy and prepregnancy BMI, family history of diabetes, hypertension, prior GDM, prior fetal macrosomia, number of abnormal 100-g/3-h OGTT values, and HbA1c (P<0.05). Prepregnancy BMI, family history of diabetes, number of abnormal 100-g/3-h OGTT values and HbA1c were statistically significant variables in the logistic regression model.

CONCLUSIONS

The probability of insulin therapy can be estimated in pregnant women with GDM based on prepregnancy BMI, family history of diabetes, number of abnormal 100-g/3-h OGTT values, and HbA1c concentration.

Hypoglycemics: pharmacokinetic considerations during pregnancy

A wide range of physiological and hormonal changes occur during pregnancy. Most begin early in the first trimester and increase by the last trimester. These changes can significantly affect pharmacokinetics and pharmacodynamics of drugs and thus may alter their safety and efficacy. Approximately 5% of pregnant women are affected by some form of diabetes, with gestational diabetes being the most prevalent. Several classes of antidiabetic drugs are currently available for the treatment of diabetes, including human insulin, its short and long analogues, and oral hypoglycemic agents. Maternal and fetal responses to these drugs can be affected by changes in absorption, distribution, and elimination in both the mother and the placental-fetal unit. This can dictate the amount of drug that can cross and the amount that is metabolized or eliminated by the placenta. Further studies are needed on the safety of antidiabetic drugs in pregnancy to clarify the extent of their transplacental passage. Specifically, in vitro placental perfusion studies in combination with controlled trials and cord blood measurements can provide insight in to the pharmacokinetics of drug transport across the placenta. This article reviews common types of antidiabetic drugs, focusing on pharmacokinetic considerations that need to be incorporated into the decision on treatment in pregnancy.

Management of gestational diabetes mellitus

The incidence of gestational diabetes mellitus (GDM) is on the increase and, if not diagnosed, managed and treated adequately, can have unfavorable maternal and fetal outcomes. Several studies have shown that glycemic values considered as adequate in the past when monitoring GDM failed to contain these adverse outcomes and randomized trials are needed to ascertain whether these targets should be lowered. Dietary restrictions remain the mainstay of GDM management and suitable physical exercise can help too. The use of rapid-acting insulin analogues (lispro and aspart) are novel treatments for improving metabolic control by reducing postprandial glycemia, while long-acting insulin analogues need to be evaluated by further studies for safety in clinical use before they can be prescribed. Numerous studies have found glyburide and metformin safe in women with GDM but more randomized controlled trials are needed, with a long-term follow-up of mother and child, to confirm these results.

New modalities in the treatment of pregnancies complicated by diabetes: drugs and devices

The development of drugs and devices in the treatment of pregnancies complicated by diabetes is in constant forward progression to compensate for pancreatic beta cell insufficiency. Maternal hyperglycemia during pregnancy is of particular interest due to the severe consequences that surface when a fetus is in development. The drugs that are currently recommended for use during pregnancy include rapid-acting insulin analogs lispro and aspart for meal-related bolus insulin and intermediate-acting NPH for basal insulin. Oral anti-diabetic agents are not recommended for use during pregnancy. Better control may be achieved with the incorporation of real-time glucose sensors and new insulin pumps with hopes of improving pregnancy outcome.

Insulin and carbohydrate metabolism

Fetal glucose exposure and consequent fetal insulin secretion is normally tightly regulated by glucose delivery from the mother during pregnancy. Maternal hyperglycaemia and gestational diabetes (GDM) are known to be detrimental to offspring, although defining the criteria for diagnosis of GDM is controversial. Recent data suggest that the risk of poor fetal outcome appears to be a continuous variable across the range of glucose control, and that the level of maternal blood glucose for a diagnosis of gestational diabetes needs to be reviewed. After birth, rapid adaptation is necessary for infants to be able to maintain independent glucose homeostasis. This adaptation is compromised in infants who are small for gestational age (SGA), premature, or large for gestational age (LGA). Interestingly, the infants who are born at the extremes of birth weight are also at increased risk of impaired glucose tolerance and diabetes in later life.

Accuracy of a single fetal weight estimation at 29-34 weeks in diabetic pregnancies: can it predict large-for-gestational-age infants at term?

OBJECTIVES

This study was undertaken to evaluate the accuracy of a single sonographic estimated fetal weight at 29-34 weeks' gestation with respect to birthweight determination in diabetic pregnancies.

STUDY DESIGN

A retrospective cohort study of 423 diabetic pregnancies with detailed fetal measurements at 29-34 weeks' gestation. Multivariate regression analysis was used to predict the birthweight. The percentiles of the estimated fetal weight and the calculated birthweight were compared with the actual birthweight percentile.

RESULTS

The mean birthweight percentile at term was significantly higher than the estimated fetal weight percentile at 29-34 weeks' gestation in the women with poor glycemic control, but not the women with good control. On multivariate analysis, the estimated fetal weight, interval from ultrasound to delivery, hemoglobin A1C level, gestational age at ultrasound, and classification of glycemic control were independently associated with the birthweight. Both the estimated fetal weight and the calculated birthweight had a low sensitivity and a low positive predictive value for predicting large-for-gestational-age infants.

CONCLUSION

Accelerated fetal growth is evident primarily in diabetic women with poor glycemic control. These fetuses cannot be identified by a single ultrasound examination at 29-34 weeks' gestation.

Use of new technologies for monitoring and treating diabetes in pregnancy

During the last century, there were two breakthroughs in diabetes management and monitoring that changed the course of treatment: the discovery of insulin and the progress in the understanding of glucose monitoring. As technology evolved, glucose monitoring and insulin administration can now be achieved in a continuous fashion. In this review, the authors focus on the utility of new technologies in the management and monitoring of diabetes in pregnancy.