Can a low-glycemic index diet reduce the need for insulin in gestational diabetes mellitus? A randomized trial

Impact of carbohydrate quantity and quality on maternal and pregnancy outcomes in gestational diabetes mellitus: A systematic review and meta-analysis

OBJECTIVE

To evaluate the impact of carbohydrate quantity and quality on maternal and pregnancy outcomes in gestational diabetes mellitus.

METHODS

Using a pre-defined search strategy, two researchers systematically searched MEDLINE, CINAHL Plus, and PubMed for randomized controlled trials comparing low-carbohydrate, low-glycaemic index, or low-glycaemic load diets with usual care in gestational diabetes mellitus. Mean differences and risk ratios were extracted.

RESULTS

Thirteen studies with 877 participants were included. Low-carbohydrate diet did not significantly differ from usual care for fasting blood glucose (3 studies; mean difference: 1.60 mmol/L; 95 % confidence interval: -1.95, 5.15), insulin requirement (2 studies; risk ratio: 1.01; 95 % confidence interval: 0.31, 3.05), birthweight (4 studies; mean difference: -0.23 kg; 95 % confidence interval: -1.90, 1.45), caesarean delivery (5 studies; risk ratio: 1.11; 95 % confidence interval: 0.66, 1.85), macrosomia (3 studies; risk ratio: 0.35; 95 % confidence interval: 0.00, 2130.64), large-for-gestational-age (2 studies; risk ratio: 0.46; 95 % confidence interval: 0.03, 7.20), and small-for-gestational-age infants (2 studies; risk ratio: 0.94; 95 % confidence interval: 0.00, 231.18). Low-glycaemic index diet did not significantly differ from usual care for the above outcomes either. However, low-glycaemic load diet reduced macrosomia risk (2 studies; risk ratio: 0.51; 95 % confidence interval: 0.43, 0.59).

CONCLUSIONS

Low-carbohydrate and low-glycaemic index diets do not differ from usual care for most maternal and foetal outcomes in gestational diabetes mellitus. But low-glycaemic load diet may reduce macrosomia risk.

Effect of low-glycemic index diet advice on pregnant outcomes in women with elevated risk of gestational diabetes mellitus: A meta-analysis of randomized controlled trails

BACKGROUND AND AIMS

The beneficial effect of low-glycemic index (GI) diet on gestational diabetes mellitus (GDM) has been suggested in many observational studies; however, results from intervention trials remain inconsistent. This study aims to estimate the effect of interventions with low-GI dietary advice on pregnant outcomes in women with elevated risk of GDM.

DESIGN

PubMed, Web of Science, Embase, and Cochrane Library databases were searched for randomized clinical trials (RCTs) through March 2022. Studies reporting the effect of low-GI diet advice intervention on maternal and fetal outcomes in pregnant women with increased risks of GDM were included. Random or fixed effects model was used to calculate combined treatment effects. Publication bias was assessed via Begg's and Egger's tests and funnel plot inspection.

RESULTS

Nine RCTs recruiting 3416 participants were included. Low-GI diet advice did not modulate the risk of GDM. Compared with control diets, low-GI diet advice significantly reduced gestational weight gain (GWG) (weighted mean differences, WMD = -0.93 kg, 95% CI: -1.31, -0.55; p < 0.001; n = 7) and the risk of premature birth (RR = 0.55, 95% CI: 0.35, 0.88; p = 0.012; n = 5). In subgroup analyses, the effect of low-GI diet interventions on premature birth was significant only in women with BMI higher than 30 kg/m2 (RR = 0.28, 95% CI: 0.10, 0.77, p = 0.014; n = 3); the significant effect on GWG was not altered by stratification of BMI and the type of GDM risk factors. No significant changes in other maternal and newborn outcomes were found.

CONCLUSIONS

Low-GI diet advice interventions during pregnancy decreased GWG and the risk of premature birth in women with elevated GDM risk; however, the interventions did not significantly prevent GDM development in these women.

The Effectiveness of Lifestyle Changes in Glycemic Control among Pregnant Women with Gestational Diabetes Mellitus

Background and Objectives: Gestational diabetes mellitus (GDM) is a type of diabetes that develops during pregnancy and affects approximately 10% of pregnant women worldwide. Understanding the impact of lifestyle changes on glycemic control in GDM is important for improving maternal and fetal outcomes and reducing the risk of diabetes in both the mother and child. The aim of this study is to evaluate the effectiveness as well as the factors affecting glycemic control by lifestyle changes in pregnant women with GDM. Materials and Methods: A descriptive cross-sectional study was conducted at three hospitals in the Thai Binh Province from June 2021 to May 2022. All pregnant women at 24-28 weeks of gestation, aged 18 years or older, were enrolled. GDM was diagnosed according to the guidelines of the International Association of the Diabetes and Pregnancy Study Groups. Lifestyle changes including diet and physical exercise were carried out for two weeks. The main outcome measured was successful glycemic control according to the 2018 ADA Recommendations for the Management and Treatment of GDM. Results: 1035 women were included and 20.2% diagnosed with GDM. After two weeks of lifestyle change intervention, 82.6% of the pregnant women with GDM had successful glycemic control. Pregnant women aged under 35 years had a 3.2 times higher rate of gestational glycemic control than those older than 35 (aOR = 3.22, p-value = 0.004). Women with a pre-pregnancy BMI of less than 25 had a higher rate of gestational glycemic control than those with a BMI of over 25 (aOR = 10.84, p-value < 0.001). Compared to women who had all three diagnostic criteria for gestational diabetes, those with two diagnostic criteria and one criterion were 3.8 times and 3 times more likely to have successful blood sugar control (aOR = 3.78, p-value = 0.01 and aOR = 3.03, p-value = 0.03, respectively). Conclusion: Lifestyle changes can be an effective measure for achieving glycemic control in women with GDM. Healthcare providers should consider individualized treatment plans based on the specific needs of each patient.

Gestational diabetes mellitus and COVID-19: The epidemic during the pandemic

During the global coronavirus disease 2019 (COVID-19) pandemic, people worldwide have experienced an unprecedented rise in psychological distress and anxiety. In addition to this challenging situation, the prevalence of diabetes mellitus (DM), a hidden epidemic, has been steadily increasing in recent years. Lower-middle-income countries have faced significant barriers in providing accessible prenatal care and promoting a healthy diet for pregnant women, and the pandemic has made these challenges even more difficult to overcome. Pregnant women are at a higher risk of developing complications such as hyper-tension, preeclampsia, and gestational diabetes, all of which can have adverse implications for both maternal and fetal health. The occurrence of gestational diabetes has been on the rise, and it is possible that the pandemic has worsened its prevalence. Although data is limited, studies conducted in Italy and Canada suggest that the pandemic has had an impact on gestational diabetes rates, especially among women in their first trimester of pregnancy. The significant disruptions to daily routines caused by the pandemic, such as limited exercise options, indicate a possible link between COVID-19 and an increased likelihood of experiencing higher levels of weight gain during pregnancy. Notably, individuals in the United States with singleton pregnancies are at a significantly higher risk of excessive gestational weight gain, making this association particularly important to consider. Although comprehensive data is currently lacking, it is important for clinical researchers to explore the possibility of establishing correlations between the stress experienced during the pandemic, its consequences such as gestational gain weight, and the increasing incidence of gestational DM. This knowledge would contribute to better preventive measures and support for pregnant individuals during challenging times.

Effect of Dietary Approaches on Glycemic Control in Patients with Type 2 Diabetes: A Systematic Review with Network Meta-Analysis of Randomized Trials

BACKGROUND

Dietary patterns play a critical role in diabetes management, while the best dietary pattern for Type 2 diabetes (T2DM) patients is still unclear. The aim of this network meta-analysis was to compare the impacts of various dietary approaches on the glycemic control of T2DM patients.

METHODS

Relevant studies were retrieved from PubMed, Embase, Web of Knowledge, Cochrane Central Register of Controlled Trials (CENTRAL), and other additional records (1949 to 31 July 2022). Eligible RCTs were those comparing different dietary approaches against each other or a control diet in individuals with T2DM for at least 6 months. We assessed the risk of bias of included studies with the Cochrane risk of bias tool and confidence of estimates with the Grading of Recommendations Assessment, Development, and Evaluation approach for network meta-analyses. In order to determine the pooled effect of each dietary approach relative to each other, we performed a network meta-analysis (NMA) for interventions for both HbA1c and fasting glucose, which enabled us to estimate the relative intervention effects by combing both direct and indirect trial evidence.

RESULTS

Forty-two RCTs comprising 4809 patients with T2DM were included in the NMA, comparing 10 dietary approaches (low-carbohydrate, moderate-carbohydrate, ketogenic, low-fat, high-protein, Mediterranean, Vegetarian/Vegan, low glycemic index, recommended, and control diets). In total, 83.3% of the studies were at a lower risk of bias or had some concerns. Findings of the NMA revealed that the ketogenic, low-carbohydrate, and low-fat diets were significantly effective in reducing HbA1c (viz., -0.73 (-1.19, -0.28), -0.69 (-1.32, -0.06), and -1.82 (-2.93, -0.71)), while moderate-carbohydrate, low glycemic index, Mediterranean, high-protein, and low-fat diets were significantly effective in reducing fasting glucose (viz., -1.30 (-1.92, -0.67), -1.26 (-2.26, -0.27), -0.95 (-1.51, -0.38), -0.89 (-1.60, -0.18) and -0.75 (-1.24, -0.27)) compared to a control diet. The clustered ranking plot for combined outcomes indicated the ketogenic, Mediterranean, moderate-carbohydrate, and low glycemic index diets had promising effects for controlling HbA1c and fasting glucose. The univariate meta-regressions showed that the mean reductions of HbA1c and fasting glucose were only significantly related to the mean weight change of the subjects.

CONCLUSIONS

For glycemic control in T2DM patients, the ketogenic diet, Mediterranean diet, moderate-carbohydrate diet, and low glycemic index diet were effective options. Although this study found the ketogenic diet superior, further high-quality and long-term studies are needed to strengthen its credibility.

Knowledge domain and research trends for Gestational Diabetes Mellitus and nutrition from 2011 to 2021: a bibliometric analysis

Objective

Nutrient management and lifestyle changes are the frontlines of treatment for all pregnant women diagnosed with Gestational Diabetes Mellitus (GDM). This study aimed to identify the global research architecture, trends, and hotpots of GDM and nutrition.

Methods

We obtained publications from the sub-databases of Science Citation Index Expanded and Social Science Citation Index sourced from the Web of Science Core Collection database on January 4, 2022, using publication years between 2011 and 2021. CiteSpace software, VOSviewer, and Microsoft Excel 2019 were used to conduct the bibliometric analyses.

Results

A growing publication trend was observed for GDM and nutrition, and this field has great potential. More GDM and nutrition research has been conducted in developed countries than developing countries. The top three authors with a high publication frequency, co-citations, and a good h-index were from the United States. There were the four studies of randomized controlled trials (RCTs) or meta-analyses of RCTs, as well as one review in the top five items of cited literature. Keywords were categorized into four clusters based on the keywords visualization.

Conclusion

It is important to strengthen the collaboration between nations of different economies to produce more high-quality research on GDM and nutrition. It may be beneficial to further study the etiology, diagnosis, and treatment of GDM based on current results to provide a new perspective on GDM and nutrition.

The Effects of a Western Diet vs. a High-Fiber Unprocessed Diet on Health Outcomes in Mice Offspring

Diet influences critical periods of growth, including gestation and early development. We hypothesized that a maternal/early life diet reflecting unprocessed dietary components would positively affect offspring metabolic and anthropometric parameters. Using 9 C57BL-6 dams, we simulated exposure to a Western diet, a high-fiber unprocessed diet (HFUD), or a control diet. The dams consumed their respective diets (Western [n = 3], HFUD [n = 3], and control [n = 3]) through 3 weeks of pregnancy and 3 weeks of weaning; their offspring consumed the diet of their mother for 4.5 weeks post weaning. Measurements included dual X-ray absorptiometry (DEXA) scans, feed consumption, body weight, blood glucose, and insulin and glycated hemoglobin (HbA1c) in the offspring. Statistical analyses included one-way ANOVA with Tukey's post hoc analysis. The offspring DEXA measures at 5 and 7.5 weeks post parturition revealed higher lean body mass development in the HFUD and control diet offspring compared to the Western diet offspring. An analysis indicated that blood glucose (p = 0.001) and HbA1c concentrations (p = 0.002) were lower among the HFUD offspring compared to the Western and control offspring. The results demonstrate that diet during gestation and early life consistent with traditional diet patterns may influence hyperglycemia and adiposity in offspring.

Effects of different dietary patterns during pregnancy on birth outcomes and glucose parameters in women with gestational diabetes mellitus: A systematic review and meta-analysis

PURPOSE

Dietary interventions are the cornerstone of gestational diabetes mellitus (GDM) treatment. This study aimed to evaluate the effects of dietary patterns during pregnancy on birth outcomes and glucose parameters in women with GDM.

METHODS

PubMed, Embase, and The CoChrane Library were searched from the time of database creation to November 30, 2021, along with manual searches. Data analyses were performed using Stata 15.4 software.

RESULTS

From 2461 studies, 27 RCTs involving 1923 women were eligible. The pooled results showed that dietary pattern interventions during pregnancy reduced birth weight (WMD: -0.14 kg; 95% CI: -0.24, -0.00), hemoglobin A_1 C (HbA_1 C) (WMD: -0.19, 95% CI: -0.34, -0.05), and macrosomia incidence (RR 0.65 [95% CI 0.48, 0.88]). Low glycemic index (GI) diet reduced macrosomia incidence (RR 0.31 [95% CI 0.11, 0.93]) and fasting plasma glucose (FPG) levels (WMD: -0.10 mmol/L; 95% CI: -0.14, -0.05); a low carbohydrate (CHO) diet reduced large for gestational age (LGA) incidence (RR 0.33 [95% CI 0.13, 0.82]) and HbA_1 C (WMD: -0.32; 95% CI: -0.51, -0.14); dietary approaches to stop hypertension (DASH) diet reduced birth weight (WMD:-0.59 kg; 95% CI: -0.64, -0.55), insulin use (RR 0.31 [95% CI 0.18, 0.56), macrosomia incidence (RR 0.12 [95% CI 0.03, 0.50]), and cesarean sections incidence (RR 0.57 [95% CI 0.40, 0.82]).

CONCLUSION

Dietary patterns during pregnancy can improve certain birth outcomes and glycemic parameters. Due to limitations in the quality and number of included studies, the above findings still need to be validated by further randomized controlled trials with high quality and large samples.

Glycemic responses to whole grain sourdough bread versus refined white bread in patients with gestational diabetes

BACKGROUND

Nutritional therapy remains a key tool for prevention and management of gestational diabetes (GDM). Carbohydrate type and absorption rate rather than the carbohydrate amount have more impact on postprandial glucose (PPG) levels in GDM. The effect of refined white bread and whole grain sourdough bread on glycemic indexes were compared in GDM patients.

METHODS

A total of 43 patients with GDM and 38 healthy pregnant women were included. A similar breakfast menu was given to both groups of patients at two different times in consecutive weeks; however, different types of bread with the same weight were used for both breakfasts; 1) white wheat (WW) bread, 2) sourdough whole grain wheat (SWGW) bread. Blood glucose, insulin and C‑peptide levels were compared before and after breakfast.

RESULTS

Fasting glucose, insulin and c‑peptide levels were similar between groups (p > 0.05). While the second hour glucose levels were similar between the groups, the first hour results of glucose, insulin and C‑peptide levels were lower in the SWGW group (p < 0.05). In the control patients, first hour glucose, insulin and C‑peptide levels were also lower in the SWGW group (p < 0.05).

CONCLUSION

The WW bread, which is more preferred in daily life routine, causes 45.5% more insulin secretion and 9.6% more first hour postprandial blood glucose compared to SWGW bread both in GDM patients and healthy pregnant women. According to the results of this study, we recommend that sourdough whole grain bread should be preferred in order to increase the success in the management of GDM.

Physical Activity, but Not Glycaemic Load, Is Associated with Lower Real-Time Glycaemic Control in Free-Living Women with Gestational Diabetes Mellitus

Maintaining blood glucose within the target range is the primary treatment goal for women with gestational diabetes mellitus (GDM). Foods with low glycaemic loads are recommended in clinical practice; however, the relative importance of other key lifestyle variables is unexplored. This pilot study explored the associations of glycaemic load, carbohydrates and physical activity parameters on blood glucose concentrations in free-living women with GDM. Twenty-nine women (28-30 weeks gestation, 34 ± 4 years) with GDM were enrolled. Continuous glucose monitoring, physical activity (ActivPAL inclinometer) and dietary intake and dietary quality were measured concurrently for 3 days. Pearson correlation analyses determined the association between glucose levels and lifestyle variables. Despite all receiving the same nutrition education, only 55% of women were following a low glycaemic load diet with a large range of carbohydrate intakes (97-267 g/day). However, the glycaemic load did not correlate with 3-hr postprandial glucose (r² = 0.021, p = 0.56) or 24-h glucose iAUC (r² = 0.021, p = 0.58). A significant relationship between total stepping time and lower 24-h glucose iAUC (r² = 0.308, p = 0.02) and nocturnal glucose (r² = 0.224, p = 0.05) was found. In free-living women with diet-controlled GDM, more physical activity, i.e., steps accumulated across the day, may be a simple and effective strategy for improving maternal blood glucose concentrations.

Effects of the Consumption of Low to Medium Glycemic Index-Based Rice on the Rate of Insulin Initiation in Patients with Gestational Diabetes: A Triple-blind, Randomized, Controlled Trial

INTRODUCTION

Medical nutritional therapy is vital in patients with diabetes. A low glycemic index (GI) is generally advised in the management of women with gestational diabetes mellitus (GDM). However, the efficacy of this advice has not been systematically examined. The purpose of this study was to determine whether recommending a low to moderate GI rice (RD43 rice; GI = 56.9) in women with GDM would reduce the number of women requiring insulin, compared with rice of high GI (Thai Hom Mali [THM] rice; GI = 80.1).

METHODS

Ninety-six participants with GDM were randomly assigned to receive either RD43 rice or THM rice.

RESULTS

The mean ± SD ages in the RD43 and THM groups were 33.1 ± 13.1 and 33.6 ± 4.1 years, respectively. The mean gestational ages at the sampling in the RD43 and THM groups were 23.3 ± 5.9 and 23.5 ± 5.4 weeks. Both groups had comparable baseline characteristics, including age, gestational age, body mass index prior to pregnancy and at enrollment, baseline postprandial (oral glucose tolerance test) plasma glucose level, and hemoglobin A_1c. Of the 48 women assigned to the RD43 group, 3 (6.3%) required insulin; in the THM group, 11 (22.9%) met the criteria for insulin therapy (P = 0.017). However, 10 of these 11 women were able to avoid insulin use by changing to the low to moderate GI rice.

CONCLUSION

Using a low to moderate GI rice in GDM effectively reduced the number of patients requiring insulin therapy. Thai Clinical Trials Registry ID: TCTR20210524007.

Increased Protein with Decreased Carbohydrate Intake Reduces Postprandial Blood Glucose Levels in Women with Gestational Diabetes: The iPRO Study

Introduction

There is an urgent need to establish an evidence base for recommendations regarding proportions of macronutrients for optimized nutritional management of gestational diabetes mellitus (GDM). Our study compared isocaloric diets in women with GDM that differed in protein and carbohydrate content with fats held constant. We hypothesized that the glucose area under the curve (AUC) would be lower with the higher protein/lower carbohydrate diet.

Research Design and Methods

This study used a random order crossover design within a controlled research unit environment. Nineteen women were randomized to treatment, with 12 participants completing both arms of the study. Blood sampling occurred preprandially and at t = 30, 60, 120, and 180" relative to meals. Inclusion criteria were confirmed diet-controlled GDMA1, singleton gestation, and with no pre-existing medical comorbidities. Mean gestational age at entrance to study = 32 (±1.76) weeks. Mean prepregnant body mass index of participants = 28.7 (±5.3) kg/m2 Participants were randomly assigned initially to either an increased protein/low carbohydrate (iPRO30%/CHO35%) diet or a lower protein/higher carbohydrate (LPRO15%/CHO50%) diet for a 36 hour inpatient stay on the research unit. All meals and snacks were prepared in a metabolic kitchen. After a 3-7 day washout period, participants were randomized to the opposite treatment.

Results

On day 2 (with confirmed overnight fasting), the average 3-hour pre- through postprandial glucose AUC was lower in iPRO30%/CHO35% treatment arm (17395.20 ± 2493.47 vs. 19172.47 ± 3484.31, p = 0.01).

Conclusion

This study is the first to demonstrate that a higher protein, lower carbohydrate meal, especially at breakfast, can result in lower postprandial blood glucose values in women with gestational diabetes. A lack of statistically significant differences at other collection time points could have been due to several factors, but most likely due to small sample size. Longer term outcomes of a higher protein diet, including maternal glycemic control, nitrogen balance, and impact on fetal growth outcomes, are needed.

Consumption of Coffee and Risk of Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis of Observational Studies

Objective: The results from epidemiologic studies on the relationship between intake of coffee and the risk of gestational diabetes mellitus (GDM) remain inconclusive. A meta-analysis was performed to achieve a comprehensive finding regarding the association between intake of coffee and the risk of GDM.

Methods: PubMed, Scopus, ISI Web of Science, and Google Scholar were searched to find articles published up to August 2021. Observational studies that reported risk estimates [risk ratios (RRs), hazard ratios (HRs), and odds ratios (ORs)] for the association of consumption of coffee with the risk of GDM in pregnant women were included. Random effects model was applied to calculate summarized risk estimate and 95% CIs for the highest vs. lowest categories of intake of coffee.

Results: Seven observational studies (three cohort, two case-control, and two cross-sectional studies) with 75,607 participants and 1,625 women with GDM met the inclusion criteria. The meta-analysis of comparing the highest vs. lowest intake of coffee categories showed no significant association between intake of coffee and risk of GDM (summarized risk estimate: 0.89; 95% CI: 0.76, 1.05; I² = 63.4%). Subgroup analysis showed that consumption of coffee had an inverse relationship with GDM in studies conducted in non-Asia countries (summarized risk estimate: 0.75; 95% CI: 0.58, 0.97; I² = 6%).

Conclusion: This study has shown that high consumption of coffee did not decrease the risk of GDM. Furthermore, large-scale cohort studies are required to confirm our findings.

Development and validation of the 'Knowledge of Gestational Diabetes (GDM)' questionnaire among a sample of women with GDM in Australia

OBJECTIVE

At present, there are few validated tools that measure women's knowledge of GDM and no tool was located, that measured effective self-management of GDM. To address this gap, this study aimed to assess the validity and reliability of the 'Knowledge of GDM' questionnaire, for use by pregnant women.

METHODS

A total of 116 pregnant women, with recently diagnosed GDM, were recruited from a public hospital in Australia. Content validity, construct validity, internal consistency reliability and test-retest reliability of the questionnaire were undertaken as part of the validation process.

RESULTS

The questionnaire performed well in terms of content validity and internal consistency. Test-retest reliability indicated that the instrument was effective at measuring knowledge of GDM over time.

CONCLUSION

we concluded that the Knowledge of GDM questionnaire is a reliable and valid measure of GDM knowledge, nutrition values and self-management principles.

PRACTICE IMPLICATIONS

The questionnaire can be used to effectively determine knowledge gaps and the information needs of pregnant women with GDM. This information can then be used to improve health literacy and provide targeted support for women to better self-manage GDM.

An evaluation of dietary intakes of a selected group of South Asian migrant women with gestational diabetes mellitus

Background: Women of South Asian descent have an increased risk of developing gestational diabetes mellitus (GDM), and type 2 diabetes mellitus compared to Caucasian women. Dietary advice provided by health practitioners to this group has been found to be culturally inappropriate. The aim of this study was to describe the dietary intakes of South Asian women with gestational diabetes and use this information to develop culturally appropriate dietary models for education and support of dietary management.Method: An in-depth diet and lifestyle survey was administered with 13 eligible women. Dietary histories were collected for pre-pregnancy, during pregnancy and post-GDM diagnosis to evaluate changes in dietary intake, diet and health beliefs and traditional foods consumed during pregnancy.Results: The diets of participants did not meet nutrient requirements for pregnancy; specific areas on concern were dietary fibre, calcium, iron, folate and iodine. Vegetarians were particularly at risk with regards to energy and protein intake. Generally dietary intakes of these women with GDM were not consistent with guidelines for management of GDM. Confusion about what they should eat for GDM, health practitioner advice and conflict with cultural expectations about foods to consume during pregnancy was evident.Conclusion: The dietary information collected from these women was used to model sample menus for GDM that were culturally appropriate and consistent with vegetarian and non-vegetarian eating patterns.

Relevance of dietary glycemic index, glycemic load and fiber intake before and during pregnancy for the risk of gestational diabetes mellitus and maternal glucose homeostasis

BACKGROUND & AIMS

To date, the prevalence of Gestational diabetes mellitus (GDM) in China was 17.5%. Given the substantial relevance of GDM for medium- and long-term health of both mother and offspring and the paucity of existing data on the link between maternal diet and glucose homeostasis during pregnancy in Asian population, additional studies are needed. To examine the relevance of dietary glycemic index (GI), glycemic load (GL) and fiber intake before and during pregnancy for the development of GDM and glucose homeostasis over the course of pregnancy.

METHODS

Cox proportional hazards analysis and linear mixed effects regressions were performed on data from 9317 women for whom three food frequency questionnaires (pre-pregnancy, 1^st and 2^nd trimesters) and biochemical measures during pregnancy were available. Investigated outcome variables included GDM risk, fasting plasma glucose (FPG), glycated hemoglobin (HbA_1C), and homeostasis model assessment insulin resistance (HOMA-IR) in the 1st, 2nd and 3rd trimesters.

RESULTS

Women in the highest tertile of dietary GI (or GL) before pregnancy, in the 1^st, or the 2^nd trimester respectively had a 12% (15%), 25% (23%) or 29% (25%) higher risk of developing GDM than those in the lowest tertile (all p for trend ≤ 0.02). Women with the highest dietary fiber intake before pregnancy, in the 1st or 2nd trimester had a 11%, 17% or 18% lower GDM risk (all p for trend ≤ 0.03). Moreover, increases in GI or GL and decreases in fiber intake over the course of pregnancy (1^st to 3^rd trimesters) were independently associated with adverse concurrent developments in FPG, HbA_1C and HOMA-IR (p ≤ 0.03).

CONCLUSIONS

Our study indicates that dietary GI, GL and fiber intake before and during pregnancy affects glucose homeostasis of pregnant Chinese women.

Nutrition Management of Gestational Diabetes Mellitus

Medical nutrition therapy (MNT) is the bedrock for the management of gestational diabetes mellitus (GDM). Several different types of dietary approaches are used globally, and there is no consensus among the various professional groups as to what constitutes an ideal approach. The conventional approach of limiting carbohydrates at the cost of increasing energy from the fat source may not be most optimal. Instead, allowing higher levels of complex, low-to-medium glycaemic index carbohydrates and adequate fibre through higher consumption of vegetables and fruits seems more beneficial. No particular diet or dietary protocol is superior to another as shown in several comparative studies. However, in each of these studies, one thing was common - the intervention arm included more intensive diet counselling and more frequent visits to the dieticians. For MNT to work, it is imperative that diet advice and nutrition counselling is provided by a dietician, which is easy to understand and use and includes healthy food options, cooking methods, and practical guidance that empower and motivate to make changes towards a healthy eating pattern. Various simple tools to achieve these objectives are available, and in the absence of qualified dieticians, they can be used to train other health care professionals to provide nutrition counselling to women with GDM. Given the impact of GDM on the future health of the mother and offspring, dietary and lifestyle behaviour changes during pregnancy in women with GDM are not only relevant for immediate pregnancy outcomes, but continued adherence is also important for future health.

Searching for Utopia, the Challenge of Standardized Medical Nutrition Therapy Prescription in Gestational Diabetes Mellitus Management: A Critical Review

Gestational diabetes mellitus (GDM) is a common pregnancy disorder and the incidence is increasing worldwide. GDM is associated with adverse maternal outcomes which may be reduced with proper management. Lifestyle modification in the form of medical nutrition therapy and physical activity, as well as self-monitoring of blood glucose levels, is the cornerstone of GDM management. Inevitably, the search for the "ultimate" diet prescription has been ongoing. Identifying the amount and type of carbohydrate to maintain blood glucose levels below targets while balancing the nutritional requirements of pregnancy and achieving gestational weight gain within recommendations is challenging. Recent developments in the area of the gut microbiota and its impact on glycemic response add another layer of complexity to the success of medical nutrition therapy. This review critically explores the challenges to dietary prescription for GDM and why utopia may never be found.

Diet and Healthy Lifestyle in the Management of Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) among pregnant women increases the risk of both short-term and long-term complications, such as birth complications, babies large for gestational age (LGA), and type 2 diabetes in both mother and offspring. Lifestyle changes are essential in the management of GDM. In this review, we seek to provide an overview of the lifestyle changes which can be recommended in the management of GDM. The diet recommended for women with GDM should contain sufficient macronutrients and micronutrients to support the growth of the foetus and, at the same time, limit postprandial glucose excursions and encourage appropriate maternal gestational weight gain. Blood glucose excursions and hyperglycaemic episodes depend on carbohydrate-intake. Therefore, nutritional counselling should focus on the type, amount, and distribution of carbohydrates in the diet. Further, physical activity has beneficial effects on glucose and insulin levels and it can contribute to a better glycaemic control.

Glenn A, M. S. Wolever T, G. Josse R, L. O’Connor D, Thompson A, D. Noseworthy R, Seider M, Sobie M, Bhatti G, Cavanagh J, Jones E, B. Darling P. Evaluation of Glycemic Index Education in People Living with Type 2 Diabetes: Participant Satisfaction, Knowledge Uptake, and Application

The glycemic index (GI) has been included in the Canadian clinical practice guidelines for type 2 diabetes (T2D) management since 2003, and even longer in other parts of the world (e.g., Australia). Despite this, dietitians have reported that GI is "too difficult for patients to understand and apply." They have called for diverse GI-utility data and evidence-informed education materials. To address these concerns, we developed and evaluated a GI education workshop and supporting materials, using the Kirkpatrick Model, for a T2D population. Participants (n = 29) with T2D attended a dietitian-facilitated workshop and received education materials. A mixed-form questionnaire (GIQ) and 3-day-diet-record were used to capture patient demographics, satisfaction, knowledge, and application, prior to and immediately after the workshop, 1-week, and 4-weeks post-education. Dietary GI was significantly lower at 1 and 4 weeks post-education (mean ± SEM; both 54 ± 1), compared to pre-education (58 ± 1; p ≤ 0.001). Participants (28/29) were satisfied with the intervention. The GI knowledge score was significantly higher post-education at baseline (83.5 ± 3.4%; p ≤ 0.001), week one (87.5 ± 2.6%; p = 0.035), and week four (87.6 ± 3.8%; p = 0.011) when compared to pre-education (53.6 ± 5.1%). A significant reduction in dietary GI was achieved by participants living with T2D, after completing the workshop, and they were able to acquire and apply GI knowledge in a relatively short period.

Diet and Nutritional Interventions with the Special Role of Myo-Inositol in Gestational Diabetes Mellitus Management. An Evidence-Based Critical Appraisal

BACKGROUND

Gestational Diabetes Mellitus (GDM), defined as glucose intolerance with onset or first recognition during pregnancy, represents one of the most common maternal-fetal complications during pregnancy and it is associated with poor perinatal outcomes. To date, GDM is a rising condition over the last decades coinciding with the ongoing epidemic of obesity and Type 2 Diabetes Mellitus (T2DM).

OBJECTIVE

The aim of this review is to discuss the role of diet and nutritional interventions in preventing GDM with the explanation of the special role of myo-inositol (MI) in this matter.

METHODS

We performed an overview of the most recent literature data on the subject with particular attention to the effectiveness of diet and nutritional interventions in the prevention of GDM with the special role of MI.

RESULTS

Nutritional intervention and physical activity before and during pregnancy are mandatory in women affected by GDM. Moreover, the availability of insulin-sensitizers such as different forms of inositol has dramatically changed the scenario, allowing the treatment of several metabolic diseases, such as those related to glucose dysbalance. Although the optimal dose, frequency, and form of MI administration need to be further investigated, diet supplementation with MI appears to be an attractive alternative for the GDM prevention as well as for the reduction of GDM-related complications.

CONCLUSIONS

More studies should be conducted to prove the most effective nutritional intervention in GDM. Regarding the potential effectiveness of MI, further evidence in multicenter, randomized controlled trials is needed to draw firm conclusions.

The Role of Dietary Carbohydrates in Gestational Diabetes

Gestational diabetes (GDM) is hyperglycemia that is recognized for the first time during pregnancy. GDM is associated with a wide range of short- and long-term adverse health consequences for both mother and offspring. It is a complex disease with a multifactorial etiology, with disturbances in glucose, lipid, inflammation and gut microbiota. Consequently, its management is complex, requiring patients to self-manage their diet, lifestyle and self-care behaviors in combination with use of insulin. In addition to nutritional recommendations for all pregnant women, special attention to dietary carbohydrate (CHO) amount and type on glucose levels is especially important in GDM. Dietary CHO are diverse, ranging from simple sugars to longer-chain oligo- and poly- saccharides which have diverse effects on blood glucose, microbial fermentation and bowel function. Studies have established that dietary CHO amount and type can impact maternal glucose and nutritional recommendations advise women with GDM to limit total intake or choose complex and low glycemic CHO. However, robust maternal and infant benefits are not consistently shown. Novel approaches which help women with GDM adhere to dietary recommendations such as diabetes-specific meal replacements (which provide a defined and complete nutritional composition with slowly-digested CHO) and continuous glucose monitors (which provide unlimited monitoring of maternal glycemic fluctuations) have shown benefits on both maternal and neonatal outcomes. Continued research is needed to understand and develop tools to facilitate patient adherence to treatment goals, individualize interventions and improve outcomes.

Evidenced-Based Nutrition for Gestational Diabetes Mellitus

PURPOSE OF REVIEW

To review the latest evidence for dietary interventions for treatment of gestational diabetes (GDM).

RECENT FINDINGS

High-quality systematic reviews demonstrate no major advantages between the low-carbohydrate or calorie-restricted diets. However, the low glycemic index (GI) diet, characterized by intake of high-quality, complex carbohydrates, demonstrated lower insulin use and reduced risk of macrosomia in multiple reviews. Recent evidence suggests the Mediterranean diet is safe in pregnancy, though trials are needed to determine its efficacy over conventional dietary advice. Currently, there are insufficient data to support the safety of the ketogenic diet for the treatment of GDM. The low GI diet may improve maternal and neonatal outcomes in GDM. The liberalized carbohydrate intake is less restrictive, culturally adaptable, and may improve long-term maternal adherence. Further research is needed to establish the optimal, most sustainable, and most acceptable medical nutrition therapy for management of women with GDM.

Intuitive eating is associated with improved health indicators at 1-year postpartum in women with gestational diabetes mellitus

We evaluated the associations between intuitive eating during and after pregnancy with metabolic health at 1-year postpartum in women with gestational diabetes mellitus and in high-risk gestational diabetes mellitus subgroups. One hundred seventeen women who consented and completed the French intuitive eating questionnaire during and after pregnancy were included. We found an association between intuitive eating during and after pregnancy with lower body mass index, weight retention, fasting glucose, and HbA1c at 1-year postpartum in women with gestational diabetes mellitus and in high-risk gestational diabetes mellitus subgroups with overweight/obese or with prediabetes in the postpartum period. Our results suggest that intuitive eating could be an effective intervention for weight and glucose control in women with gestational diabetes mellitus.

Intuitive eating is associated with weight and glucose control during pregnancy and in the early postpartum period in women with gestational diabetes mellitus (GDM): A clinical cohort study

INTRODUCTION

High pre-pregnancy weight and body mass index (BMI) increase the risk of gestational diabetes mellitus (GDM) and diabetes after pregnancy. To tackle weight and metabolic health problems, there is a need to investigate novel lifestyle approaches. Outside of pregnancy, higher adherence to intuitive eating (IE) is associated with lower BMI and improved glycemic control. This study investigated the association between IE and metabolic health during pregnancy and in the early postpartum period among women with GDM.

METHODS

Two-hundred and fourteen consecutive women aged ≥18, diagnosed with GDM between 2015 and 2017 and completed the "Eating for Physical rather than Emotional Reasons (EPR)" and "Reliance on Hunger and Satiety cues (RHSC) subscales" of the French Intuitive Eating Scale-2 (IES-2) questionnaire at the first GDM clinic visit were included in this study.

RESULTS

Participants' mean age was 33.32 ± 5.20 years. Their weight and BMI before pregnancy were 68.18 ± 14.83 kg and 25.30 ± 5.19 kg/m² respectively. After adjusting for confounding variables, the cross-sectional analyses showed that the two subscales of IES-2 at the first GDM visit were associated with lower weight and BMI before pregnancy, and lower weight at the first GDM visit (β = -0.181 to -0.215, all p ≤ 0.008). In addition, the EPR subscale was associated with HbA1c and fasting plasma glucose at the first GDM visit (β = -0.170 and to -0.196; all p ≤ 0.016). In the longitudinal analyses, both subscales of IES-2 at first GDM visit were associated with lower weight at the end of pregnancy, BMI and fasting plasma glucose at 6-8 weeks postpartum (β = -0.143 to -0.218, all p ≤ 0.040) after adjusting for confounders.

CONCLUSIONS

Increase adherence to IE could represent a novel approach to weight and glucose control during and after pregnancy in women with GDM.

Low-Carbohydrate Diets for Gestational Diabetes

Nutrition therapy provides the foundation for treatment of gestational diabetes (GDM), and has historically been based on restricting carbohydrate (CHO) intake. In this paper, randomized controlled trials (RCTs) are reviewed to assess the effects of both low- and higher CHO nutrition approaches in GDM. The prevailing pattern across the evidence underscores that although CHO restriction improves glycemia at least in the short-term, similar outcomes could be achievable using less restrictive approaches that may not exacerbate IR. The quality of existing studies is limited, in part due to dietary non-adherence and confounding effects of treatment with insulin or oral medication. Recent evidence suggests that modified nutritional manipulation in GDM from usual intake, including but not limited to CHO restriction, improves maternal glucose and lowers infant birthweight. This creates a platform for future studies to further clarify the impact of multiple nutritional patterns in GDM on both maternal and infant outcomes.

Gestational Diabetes Mellitus: The Impact of Carbohydrate Quality in Diet

Gestational diabetes mellitus (GDM) is defined as “glucose intolerance that is first diagnosed during pregnancy”. Mothers with GDM and their infants may experience both short and long term complications. Dietary intervention is the first therapeutic strategy. If good glycaemic control is not achieved, insulin therapy is recommended. There is no consensus on which nutritional approach should be used in GDM. In the last few years, there has been growing evidence of the benefits of a low glycaemic index (LGI) diet on diabetes and cardiovascular disease. The effect of a LGI diet on GDM incidence has been investigated as well. Several studies observed a lower incidence of GDM in LGI diet arms, without adverse maternal and fetal outcomes. The main positive effect of the LGI diet was the reduction of 2-h post-prandial glucose (PPG). Several studies have also evaluated the effect of the LGI diet in GDM treatment. Overall, the LGI diet might have beneficial effects on certain outcomes, such as 2-h PPG, fasting plasma glucose and lipid profile in patients with GDM. Indeed, most studies observed a significant reduction in insulin requirement. Overall, according to current evidence, the LGI nutritional approach is safe and it might therefore be considered in clinical care for GDM.

Inverse relation between fruit and vegetable intake and the risk of gestational diabetes mellitus

Background: The aim of this study was to investigate the association of intakes of fruit, vegetable and dairy with gestational diabetes mellitus (GDM). Methods: This prospective study was conducted over a 17 month period, on a random sample of pregnant women (n = 1026), aged 18-45 y, in their first half of pregnancy, attending prenatal clinics in five hospitals' affiliated to universities of medical sciences in different districts of Tehran, Iran. Dietary intakes were assessed during gestational age ≤ 6 weeks using a 168-item validated semi-quantitative food frequency questionnaire. Between 24 and 28 weeks of gestation, all pregnant women underwent a scheduled 100 g 3-h oral glucose tolerance test. Diagnosis of GDM was based on criteria set by the American Diabetes Association. Results: Of 1026 study participants, 71 had GDM, with a mean age and pre-pregnancy BMI of 26.7 ± 4.3 y and 25.4 ± 4.5 Kg/m², respectively. High fruit and vegetable intakes were negatively associated with GDM risk. Compared with women who consumed < 2.1 servings/day, odds ratio (ORs) for those who consumed ≥ 4.9 servings/day was 0.44 (95% CI: 0.20-0.93), after adjustment for confounding factors. Fruit and vegetable intakes were significantly and inversely associated with the GDM; ORs (95% CIs) for GDM among participants with the highest, compared to the lowest quartiles were 0.48 (0.18-0.89) for fruit and 0.46 (0.22-0.99) for vegetables intake. No association was found between dairy products and GDM. Conclusions: Fruit and vegetable consumption in women of reproductive age have beneficial effects in the prevention of GDM.

Maternal dietary glycaemic change during gestation influences insulin-related gene methylation in the placental tissue: a genome-wide methylation analysis

Background

Studies have shown that the effects of maternal nutrition exposure during gestation influence metabolic risk in early life through an epigenetic mechanism. Low glycaemic index (GI) diets benefit both maternal and neonatal gestational outcomes. We hypothesize that maternal dietary GI or glycaemic load (GL) changes during pregnancy impact placental DNA methylation, especially in insulin resistance-related genes.

Methods

From a clinical trial of overweight pregnant women, 12 subjects who successfully reduced their GI and another 12 whose GI increased despite the intervention were selected. A genome-wide differential methylation analysis of placental tissue DNA was conducted, followed by bioinformatic annotation and validation analysis. The distribution of genome-wide differentially methylated regions (DMRs) and CpG sites was described. Six CpG sites in regulatory regions of four insulin-related genes (PLIN1, CPT1B, SSTR4, and CIDEA) were selectively validated by pyrosequencing. Pairwise Spearman correlation analysis was performed to test methylation–phenotype association in an additional 153 subjects from the same trial. Correlation between methylation of significant sites and placental mRNA expression of SSTR4 was also analysed.

Results

Dietary GI decreased by 24.3 (26.2–20.1) in the group who responded appropriately to the intervention and increased by 19.6 (15.2–29.1) in the comparison group. Epigenome-wide analysis identified 108 DMRs and 365 CpG sites with P < 0.05 adjusted by false discovery rate, distributed over all chromosomes. The methylation level of cg05009389 in the 3′ UTR of PLIN1 was negatively correlated with maternal weight gain (ρ = − 0.21, P = 0.027) and increase in insulin levels (ρ = − 0.24, P = 0.015) during gestation. Methylation levels of cg17586860 and cg18197392 in the 5′ UTR region of SSTR4 were negatively correlated with changes in dietary carbohydrate intake (ρ = − 0.24, Ps ≤ 0.006) and GL across gestation (ρ = − 0.23, Ps ≤ .008). This correlation survived the adjustment for maternal factors such as dietary GI, body mass index, and gestational diabetes. Up to 89% of cg18197392 methylation was explained by GL change. Cg14631053 methylation correlated positively with mRNA expression of SSTR4 in the placenta (ρ = 0.20, P = 0.037).

Conclusions

We provide the first evidence that maternal dietary GI changes during gestation may impact placental DNA methylation of insulin regulation genes. This supports the hypothesis that placental methylation may be the epigenetic mechanism through which maternal diet influences the metabolic health of offspring.

Electronic supplementary material

The online version of this article (10.1186/s12263-019-0634-x) contains supplementary material, which is available to authorized users.

Effectiveness of Low Glycemic Index Diet Consultations Through a Diet Glycemic Assessment App Tool on Maternal and Neonatal Insulin Resistance: A Randomized Controlled Trial

Background

Low glycemic index (LGI) diet has shown to be effective in reducing maternal and neonatal complications in high-risk pregnancies.

Objective

This trial aimed to examine the effectiveness of individualized LGI diet consultations based on the accurate diet glycemic load (GL) assessment tool on maternal and neonatal insulin resistance levels and diet behavior changes in overweight and obese pregnant women.

Methods

Overweight and obese pregnant women were recruited before 16 weeks of gestation and randomized to the LGI diet arm or the control arm. All participants received standard dietary education according to the Chinese Dietary Guide for Pregnant Women. In the intervention arm, additional individualized dietary GL assessments were performed using an app and instructions of lowering diet glycemic index (GI) to achieve LGI diet were provided by a clinical dietitian at early, middle, and late gestation. Primary outcomes were serum insulin at late gestation, incidence of gestational diabetes mellitus (GDM) for mothers, and cord blood C-peptide level of neonates.

Results

In total, 400 subjects were randomized and received different interventions. There were no significant differences in maternal serum insulin levels (13.2 [9.3−13.2] uU/mL vs 12.4 [10.5−12.4] uU/mL), incidence of GDM (45 [22.5%] vs 43 [21.5%]), or cord blood C-peptide levels (mean 0.9ng/mL [SD 0.7] vs mean 0.8ng/mL [SD 0.6]) in the intervention group compared with the controls. The diet GI at late gestation was similar (mean 63.2 [SD 10.4] vs mean 64.3 [SD 10.4]), whereas greater diet fiber intake was observed in the intervention group (mean 11.6 grams [SD 8.0] vs mean 9.0 grams [SD 5.6]; P=.006). Adherence measurements did not significantly differ between 2 groups.

Conclusions

Individualized LGI diet consultations for overweight and obese pregnant women failed to make a significant difference in maternal or neonatal insulin resistance compared with the standard gestational diet consultation.

Trial Registration

ClinicalTrials.gov NCT01628835; http://clinicaltrials.gov/ct2/show/NCT01628835 (Archived by WebCite at http://www.webcitation.org/77LHgWP0k)

Insights on Medical Nutrition Therapy for Type 2 Diabetes Mellitus: An Indian Perspective

It is critical to integrate medical nutrition therapy (MNT) provided by a registered dietician (RD) into primary care of type 2 diabetes mellitus (T2DM). This is necessary to achieve the goals of improving overall metabolic measures beyond calorie restriction and weight loss. Misconceptions about nutrition in T2DM add to the challenges of executing MNT in a culturally sensitive population. The current review provides insights into MNT for the prevention and management of T2DM in India, based on both evidence and experience. It revisits historical Indian studies and provides information on appropriate dietary intake of carbohydrates (60-70%), proteins (~ 20%) and fats (10%) that will be acceptable and beneficial in an Indian T2DM population. It discusses nuances of types of carbohydrates and fats and explains associations of increased dietary fiber intake, balanced intake of low and high glycemic index foods and substitution of saturated fats with plant-based polyunsaturated fats in improving outcomes of T2DM and attenuating risk factors. The article also deliberates upon special patient populations with comorbid conditions and diseases and the necessary adjustments needed in their nutritional care. It outlines a step-wise approach to MNT involving a careful interplay of nutrition assessment, diagnosis, individualization and patient counseling. Overall, the success of MNT relies on providing accurate, acceptable and appropriate dietary choices for continued patient adherence. Collaborative efforts from diabetologists, endocrinologists, internists and RDs are required to prioritize and implement MNT in diabetes practice in India.Funding: Signutra Inc.

Nutrition therapy within and beyond gestational diabetes

With the global rising prevalence of gestational diabetes (GDM), an adaptable, economical approach to nutrition therapy that effectively controls maternal glycemia while promoting normal fetal growth will have far-reaching implications. The conventional focus has been to rigidly limit all types of carbohydrate. While controlling glucose, this approach fosters maternal anxiety and is a primary barrier to adherence. Many mothers substitute fat for carbohydrate, which may unintentionally enhance lipolysis, promote elevated free fatty acids (FFA), and worsen maternal insulin resistance (IR). Nutrition that worsens IR may facilitate nutrient shunting across the placenta, promoting excess fetal fat accretion. Evidence suggests that liberalizing higher quality, nutrient-dense carbohydrates results in controlled fasting/postprandial glucose, lower FFA, improved insulin action, vascular benefits, and may reduce excess infant adiposity. Thus, a less carbohydrate-restricted approach may improve maternal adherence when combined with higher quality carbohydrates, lower fat, appropriate caloric intake, and ethnically acceptable foods. Such a diet can be culturally sensitive, socioeconomically attentive, minimize further weight gain in GDM, with potential relevance for pregnancies complicated by overweight/obesity. Future research is needed to better understand the effect of macronutrient composition on the placenta and gut microbiome, the benefits/risks of nonnutritive sweeteners, and whether precision-nutrition is beneficial in pregnancy.

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.

A Slow-Digesting, Low-Glycemic Load Nutritional Beverage Improves Glucose Tolerance in Obese Pregnant Women Without Gestational Diabetes

BACKGROUND

Obesity is a risk factor for gestational diabetes (gestational diabetes). Low-glycemic index diets attenuate hyperglycemia. We designed a study to determine whether a slow-digesting, low-glycemic load (SD-LGL) beverage improves glucose tolerance in obese pregnant women without GDM.

METHODS

This was a 3-arm comparison study comparing the effects of an SD-LGL nutritional beverage (glycemic load [GL] 730), an isocaloric control beverage (GL 1124), and habitual diet on glycemia in obese pregnant women. Sixteen women (mean body mass index 37 kg/m²) were recruited at 24-28 weeks to receive either the SD-LGL or eucaloric control beverage. This was consumed with breakfast and as a midafternoon snack over 2 days with a controlled diet. Following a 2-day washout period of habitual diet, women completed 2 days on the alternative beverage with controlled diet. A 10-h fast preceded each intervention phase. Twenty-four hour glucose was measured using continuous glucose monitoring.

RESULTS

Consumption of the lower GL beverage was associated with improved measures of glycemia, compared with the control beverage and habitual diet at different time periods. Glucose estimates for control versus SD-LDL at 24 h (0.23 mmol/L [0.16 to 0.31], P < 0.001), daytime (0.26 mmol/L [0.18 to 0.34], P < 0.001), and nighttime (0.05 mmol/L [-0.01 to 0.11], P = 0.09). Postprandial glucose was lower after breakfast but not after dinner, compared with the control beverage (0.09 mmol/L [0.01 to 0.18], P = 0.03).

CONCLUSION

A slow-digesting, low-glycemic nutritional beverage may facilitate improved glucose control in obese pregnant women. To address potential benefit for clinical outcomes, a randomized controlled trial is warranted.

Gestational Diabetes: Underpinning Principles, Surveillance, and Management

Gestational diabetes mellitus (GDM) is carbohydrate intolerance resulting in hyperglycemia with onset during pregnancy. The article aims to provide clinicians with a working framework to minimize maternal and neonatal morbidity. Landmark historical and recent data are reviewed and presented to provide clinicians with a quick, easy reference for recognition and management of GDM. Data presented tie in insights with underlying pathophysiologic processes leading to GDM. Screening and diagnostic thresholds are discussed along with management upon diagnosis. Good clinical practice regarding screening, diagnosis, and management of GDM effectively reduces risk and improves outcomes of women and fetuses in affected pregnancies.

Maternal glycemic index and glycemic load in pregnancy and offspring metabolic health in childhood and adolescence-a cohort study of 68,471 mother-offspring dyads from the Danish National Birth Cohort

BACKGROUND

High glycemic index (GI) and glycemic load (GL) as indicators of carbohydrate quality and quantity have been found to increase risk of metabolic outcomes in adults. Whether carbohydrate quality may influence metabolic programming already in early life is unknown. We examined the association of maternal GI and GL with offspring body mass index (BMI) in the first 7 years of life among 68,471 mother-offspring dyads from the Danish National Birth Cohort (DNBC). In a sub-cohort of offspring with clinical data (n = 1234) that included 608 dyads exposed to gestational diabetes mellitus (GDM), we also examined the relation to metabolic health at 9-16 years.

METHODS

Maternal GI and GL were quantified using a mid-pregnancy food frequency questionnaire. We used birth weight and length to calculate offspring's ponderal index. Age- and sex-specific BMI z scores at 5 mo, 12 mo, and 7 y were standardized against WHO reference data. In the clinical cohort, we quantified body composition, HOMA-IR, and HOMA-B. We used multivariable mixed linear and Poisson regression to model the associations.

RESULTS

Median (IQR) of GI and GL were 83 (63-111) and 241 (180-333) g/day, respectively. We found that GI (Q4 vs. Q1:1.09, 95%CI: 1.03, 1.15) and GL (Q4 vs. Q1:1.10, 95%CI: 1.05, 1.16) modestly increased the relative risk of large-for gestational age (LGA). In the clinical sub-cohort, we observed a potential increase in offspring HOMA-IR, adiposity, and metabolic syndrome z score with higher maternal GI and GI. These associations were stronger among the GDM-exposed offspring, but the CI included the null value.

CONCLUSION

We found associations of GI and GL in pregnancy with offspring LGA. Potential long-term benefits to offspring exposed to GDM need to be confirmed in larger, well-powered studies.

Influence of low-glycemic index diet for gestational diabetes: a meta-analysis of randomized controlled trials

Background: Low-glycemic index (GI) diet might be beneficial for gestational diabetes. However, the results remained controversial. We conducted a systematic review and meta-analysis to explore the influence of low-GI diet on gestational diabetes.Methods: PubMed, EMbase, Web of Science, EBSCO, and Cochrane library databases were systematically searched. Randomized controlled trials (RCTs) assessing the effect of low-GI diet on gestational diabetes were included. Two investigators independently searched articles, extracted data, and assessed the quality of included studies. This meta-analysis was performed using the random-effect model.Results: Six RCTs involving 532 patients were included in the meta-analysis. Overall, compared with a control intervention in gestational diabetes, low-GI diet was found to significantly reduce 2 h postprandial glucose (Std. MD = -0.46; 95% CI = -0.82 to -0.10; p = .01), but demonstrated no substantial influence on fasting plasma glucose (Std. MD = -0.24; 95% CI = -0.72 to 0.24; p = .33), HbA1c (Std. MD = 0.01; 95% CI = -0.29 to 0.31; p = .94), birth weight (Std. MD = -0.17; 95% CI = -0.41 to 0.06; p = .15), macrosomia (Std. MD = 0.45; 95% CI = 0.16 to 1.30; p = .14) and insulin requirement (Std. MD = 0.91; 95% CI = 0.68 to 1.22; p = .55).Conclusions: Compared with control intervention in gestational diabetes, low-GI diet was found to significantly decrease 2 h postprandial glucose, but showed no notable impact on fasting plasma glucose, HbA1c, birth weight, macrosomia, and insulin requirement.

Treatments for women with gestational diabetes mellitus: an overview of Cochrane systematic reviews

BACKGROUND

Successful treatments for gestational diabetes mellitus (GDM) have the potential to improve health outcomes for women with GDM and their babies.

OBJECTIVES

To provide a comprehensive synthesis of evidence from Cochrane systematic reviews of the benefits and harms associated with interventions for treating GDM on women and their babies.

METHODS

We searched the Cochrane Database of Systematic Reviews (5 January 2018) for reviews of treatment/management for women with GDM. Reviews of pregnant women with pre-existing diabetes were excluded.Two overview authors independently assessed reviews for inclusion, quality (AMSTAR; ROBIS), quality of evidence (GRADE), and extracted data.

MAIN RESULTS

We included 14 reviews. Of these, 10 provided relevant high-quality and low-risk of bias data (AMSTAR and ROBIS) from 128 randomised controlled trials (RCTs), 27 comparisons, 17,984 women, 16,305 babies, and 1441 children. Evidence ranged from high- to very low-quality (GRADE). Only one effective intervention was found for treating women with GDM.EffectiveLifestyle versus usual careLifestyle intervention versus usual care probably reduces large-for-gestational age (risk ratio (RR) 0.60, 95% confidence interval (CI) 0.50 to 0.71; 6 RCTs, N = 2994; GRADE moderate-quality).PromisingNo evidence for any outcome for any comparison could be classified to this category.Ineffective or possibly harmful Lifestyle versus usual careLifestyle intervention versus usual care probably increases the risk of induction of labour (IOL) suggesting possible harm (average RR 1.20, 95% CI 0.99 to 1.46; 4 RCTs, N = 2699; GRADE moderate-quality).Exercise versus controlExercise intervention versus control for return to pre-pregnancy weight suggested ineffectiveness (body mass index, BMI) MD 0.11 kg/m², 95% CI -1.04 to 1.26; 3 RCTs, N = 254; GRADE moderate-quality).Insulin versus oral therapyInsulin intervention versus oral therapy probably increases the risk of IOL suggesting possible harm (RR 1.3, 95% CI 0.96 to 1.75; 3 RCTs, N = 348; GRADE moderate-quality).Probably ineffective or harmful interventionsInsulin versus oral therapyFor insulin compared to oral therapy there is probably an increased risk of the hypertensive disorders of pregnancy (RR 1.89, 95% CI 1.14 to 3.12; 4 RCTs, N = 1214; GRADE moderate-quality).InconclusiveLifestyle versus usual careThe evidence for childhood adiposity kg/m² (RR 0.91, 95% CI 0.75 to 1.11; 3 RCTs, N = 767; GRADE moderate-quality) and hypoglycaemia was inconclusive (average RR 0.99, 95% CI 0.65 to 1.52; 6 RCTs, N = 3000; GRADE moderate-quality).Exercise versus controlThe evidence for caesarean section (RR 0.86, 95% CI 0.63 to 1.16; 5 RCTs, N = 316; GRADE moderate quality) and perinatal death or serious morbidity composite was inconclusive (RR 0.56, 95% CI 0.12 to 2.61; 2 RCTs, N = 169; GRADE moderate-quality).Insulin versus oral therapyThe evidence for the following outcomes was inconclusive: pre-eclampsia (RR 1.14, 95% CI 0.86 to 1.52; 10 RCTs, N = 2060), caesarean section (RR 1.03, 95% CI 0.93 to 1.14; 17 RCTs, N = 1988), large-for-gestational age (average RR 1.01, 95% CI 0.76 to 1.35; 13 RCTs, N = 2352), and perinatal death or serious morbidity composite (RR 1.03; 95% CI 0.84 to 1.26; 2 RCTs, N = 760). GRADE assessment was moderate-quality for these outcomes.Insulin versus dietThe evidence for perinatal mortality was inconclusive (RR 0.74, 95% CI 0.41 to 1.33; 4 RCTs, N = 1137; GRADE moderate-quality).Insulin versus insulinThe evidence for insulin aspart versus lispro for risk of caesarean section was inconclusive (RR 1.00, 95% CI 0.91 to 1.09; 3 RCTs, N = 410; GRADE moderate quality).No conclusions possibleNo conclusions were possible for: lifestyle versus usual care (perineal trauma, postnatal depression, neonatal adiposity, number of antenatal visits/admissions); diet versus control (pre-eclampsia, caesarean section); myo-inositol versus placebo (hypoglycaemia); metformin versus glibenclamide (hypertensive disorders of pregnancy, pregnancy-induced hypertension, death or serious morbidity composite, insulin versus oral therapy (development of type 2 diabetes); intensive management versus routine care (IOL, large-for-gestational age); post- versus pre-prandial glucose monitoring (large-for-gestational age). The evidence ranged from moderate-, low- and very low-quality.

AUTHORS' CONCLUSIONS

Currently there is insufficient high-quality evidence about the effects on health outcomes of relevance for women with GDM and their babies for many of the comparisons in this overview comparing treatment interventions for women with GDM. Lifestyle changes (including as a minimum healthy eating, physical activity and self-monitoring of blood sugar levels) was the only intervention that showed possible health improvements for women and their babies. Lifestyle interventions may result in fewer babies being large. Conversely, in terms of harms, lifestyle interventions may also increase the number of inductions. Taking insulin was also associated with an increase in hypertensive disorders, when compared to oral therapy. There was very limited information on long-term health and health services costs. Further high-quality research is needed.

Gestational Diabetes Mellitus and Diet: A Systematic Review and Meta-analysis of Randomized Controlled Trials Examining the Impact of Modified Dietary Interventions on Maternal Glucose Control and Neonatal Birth Weight

OBJECTIVE

Medical nutrition therapy is a mainstay of gestational diabetes mellitus (GDM) treatment. However, data are limited regarding the optimal diet for achieving euglycemia and improved perinatal outcomes. This study aims to investigate whether modified dietary interventions are associated with improved glycemia and/or improved birth weight outcomes in women with GDM when compared with control dietary interventions.

RESEARCH DESIGN AND METHODS

Data from published randomized controlled trials that reported on dietary components, maternal glycemia, and birth weight were gathered from 12 databases. Data were extracted in duplicate using prespecified forms.

RESULTS

From 2,269 records screened, 18 randomized controlled trials involving 1,151 women were included. Pooled analysis demonstrated that for modified dietary interventions when compared with control subjects, there was a larger decrease in fasting and postprandial glucose (-4.07 mg/dL [95% CI -7.58, -0.57]; P = 0.02 and -7.78 mg/dL [95% CI -12.27, -3.29]; P = 0.0007, respectively) and a lower need for medication treatment (relative risk 0.65 [95% CI 0.47, 0.88]; P = 0.006). For neonatal outcomes, analysis of 16 randomized controlled trials including 841 participants showed that modified dietary interventions were associated with lower infant birth weight (-170.62 g [95% CI -333.64, -7.60]; P = 0.04) and less macrosomia (relative risk 0.49 [95% CI 0.27, 0.88]; P = 0.02). The quality of evidence for these outcomes was low to very low. Baseline differences between groups in postprandial glucose may have influenced glucose-related outcomes. As well, relatively small numbers of study participants limit between-diet comparison.

CONCLUSIONS

Modified dietary interventions favorably influenced outcomes related to maternal glycemia and birth weight. This indicates that there is room for improvement in usual dietary advice for women with GDM.

Initial group dietary education compared to individual education in gestational diabetes mellitus management: Do outcomes differ?

AIMS

To assess the effectiveness of Initial Group versus Initial Individual GDM dietary education in terms of insulin requirements and pregnancy outcomes.

METHODS

A retrospective audit of clinical data was conducted where English speaking women who received initial education in a group setting (01-2-2012 to 01-2-2014) (Group), were compared to women who received initial individual education with a dietitian (1-2-2010 to 31-1-2012) (Individual), all followed by one individual dietitian appointment. The same dietary information was provided in both settings. Data collected included: attendance rates, insulin requirements, maternal weight gain, and rates of adverse birth outcomes. Data were compared by t-test or Chi-squared test. Multivariable logistic regression analysis was conducted to determine independent predictors of insulin therapy.

RESULTS

Of 743 women; (362 Group and 381 Individual), Group women had a lower HbA1c at GDM diagnosis 5.3 ± 0.6% versus 5.5 ± 0.5% (34 ± 6.6 mmol/mol versus 37 ± 5.5 mmol/mol p < 0.0001). There were no other differences in baseline characteristics. More Group women required insulin (42.0% versus 34.6%, p = 0.048). Group education was found to be an independent predictor of insulin therapy (OR = 1.9 [1.29, 2.75] p < 0.001).

CONCLUSIONS

Despite adjusting for all known potential confounders, unlike Individual education, Group education remained a significant predictor of insulin therapy (but resulted in similar therapeutic and pregnancy outcomes to Individual education).

Gestational Diabetes: Diagnosis, Classification, and Clinical Care

Gestational diabetes mellitus (GDM) affects approximately 6% of pregnant women, and prevalence is increasing in parallel with the obesity epidemic. Protocols for screening/diagnosing GDM are controversial with several guidelines available. Treatment of GDM results in a reduction in the incidence of preeclampsia, shoulder dystocia, and macrosomia. If diet and lifestyle changes do not result in target glucose levels, then treatment with metformin, glyburide, or insulin should begin. It is generally recommended that pregnancies complicated by GDM do not go beyond term. For women identified to have prediabetes, intensive lifestyle intervention and metformin have been shown to prevent or delay progression to type 2 diabetes.

The effects of various diets on glycemic outcomes during pregnancy: A systematic review and network meta-analysis

Aims

Evidence to support dietary modifications to improve glycemia during pregnancy is limited, and the benefits of diet beyond limiting gestational weight gain is unclear. Therefore, a systematic review and network meta-analysis of randomized trials was conducted to compare the effects of various common diets, stratified by the addition of gestational weight gain advice, on fasting glucose and insulin, hemoglobin A1c (Hb_A1c), and homeostatic model assessment for insulin resistance (HOMA-IR) in pregnant women.

Methods

MEDLINE, EMBASE, Cochrane database, and reference lists of published studies were searched through April 2017. Randomized trials directly comparing two or more diets for ≥2-weeks were eligible. Bayesian network meta-analysis was performed for fasting glucose. Owing to a lack of similar dietary comparisons, a standard pairwise meta-analysis for the other glycemic outcomes was performed. The certainty of the pooled effect estimates was assessed using the GRADE tool.

Results

Twenty-one trials (1,865 participants) were included. In general, when given alongside gestational weight gain advice, fasting glucose improved in most diets compared to diets that gave gestational weight gain advice only. However, fasting glucose increased in high unsaturated or monounsaturated fatty acids diets. In the absence of gestational weight gain advice, fasting glucose improved in DASH-style diets compared to standard of care. Although most were non-significant, similar trends were observed for these same diets for the other glycemic outcomes. Dietary comparisons ranged from moderate to very low in quality of evidence.

Conclusion/Interpretation

Alongside with gestational weight gain advice, most diets, with the exception of a high unsaturated or a high monounsaturated fatty acid diet, demonstrated a fasting glucose improvement compared with gestational weight gain advice only. When gestational weight gain advice was not given, the DASH-style diet appeared optimal on fasting glucose. However, a small number of trials were identified and most dietary comparisons were underpowered to detect differences in glycemic outcomes. Further studies that are high in quality and adequately powered are needed to confirm these findings.

Registration

PROSPERO CRD42015026008

Birth weight and its relation with medical nutrition therapy in gestational diabetes

PURPOSE

The cornerstone in treatment of gestational diabetes mellitus (GDM) is medical nutrition therapy (MNT), but the effect on birth weight is disputed. The birth weight was evaluated with respect to length of MNT and adherence to diet.

METHODS

We performed a cohort study on 436 women with GDM and 254 non-diabetic women. Women with a normal oral glucose tolerance test were included as controls as they had similar background predisposition as the women with GDM. The GDM women were subdivided according to MNT and the nutritional status was further stratified according to adherence to the current dietary guidelines.

RESULTS

Birth weight above 4 kg was more prevalent in the non-diabetic women compared to the diet-treated GDM women (27 vs. 18%, p = 0.012) but similar to the GDM women who had no MNT (24%). Lower birth weight was associated with longer duration of MNT (r = -0.13, p = 0.021). The birth weight was 1.2 g lower per day of treatment.

CONCLUSIONS

Medical nutrition therapy was associated with reduction of the fetal weight in women with GDM and the weight decreases with length of treatment. Birth weight above 4 kg was as prominent in the non-diabetic women as in the women with GDM without MNT.

Effect of Probiotics on Metabolic Outcomes in Pregnant Women with Gestational Diabetes: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

The metabolic effects of probiotic administration in women with gestational diabetes mellitus (GDM) is unknown. The objective of this review was to investigate the effect of probiotics on fasting plasma glucose (FPG), insulin resistance (HOMA-IR) and LDL-cholesterol levels in pregnant women diagnosed with GDM. Seven electronic databases were searched for RCTs published in English between 2001 and 2017 investigating the metabolic effects of a 6-8 week dietary probiotic intervention in pregnant women following diagnosis with GDM. Eligible studies were assessed for risk of bias and subjected to qualitative and quantitative synthesis using a random effects model meta-analyses. Four high quality RCTs involving 288 participants were included in the review. Probiotic supplementation was not effective in decreasing FBG (Mean Difference = -0.13; 95% CI -0.32, 0.06, p = 0.18) or LDL-cholesterol (-0.16; 95% CI -0.45, 0.13, p = 0.67) in women with GDM. However, a significant reduction in HOMA-IR was observed following probiotic supplementation (-0.69; 95% CI -1.24, -0.14, p = 0.01). There were no significant differences in gestational weight gain, delivery method or neonatal outcomes between experimental and control groups, and no adverse effects of the probiotics were reported. Probiotic supplementation for 6-8 weeks resulted in a significant reduction in insulin resistance in pregnant women diagnosed with GDM. The use of probiotic supplementation is promising as a potential therapy to assist in the metabolic management of GDM. Further high quality studies of longer duration are required to determine the safety, optimal dose and ideal bacterial composition of probiotics before their routine use can be recommended in this patient group.

Lifestyle interventions for the treatment of women with gestational diabetes

BACKGROUND

Gestational diabetes (GDM) is glucose intolerance, first recognised in pregnancy and usually resolving after birth. GDM is associated with both short- and long-term adverse effects for the mother and her infant. Lifestyle interventions are the primary therapeutic strategy for many women with GDM.

OBJECTIVES

To evaluate the effects of combined lifestyle interventions with or without pharmacotherapy in treating women with gestational diabetes.

SEARCH METHODS

We searched the Pregnancy and Childbirth Group's Trials Register (14 May 2016), ClinicalTrials.gov, WHO International Clinical Trials Registry Platform (ICTRP) (14th May 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

We included only randomised controlled trials comparing a lifestyle intervention with usual care or another intervention for the treatment of pregnant women with GDM. Quasi-randomised trials were excluded. Cross-over trials were not eligible for inclusion. Women with pre-existing type 1 or type 2 diabetes were excluded.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by the Cochrane Collaboration. All selection of studies, data extraction was conducted independently by two review authors.

MAIN RESULTS

Fifteen trials (in 45 reports) are included in this review (4501 women, 3768 infants). None of the trials were funded by a conditional grant from a pharmaceutical company. The lifestyle interventions included a wide variety of components such as education, diet, exercise and self-monitoring of blood glucose. The control group included usual antenatal care or diet alone. Using GRADE methodology, the quality of the evidence ranged from high to very low quality. The main reasons for downgrading evidence were inconsistency and risk of bias. We summarised the following data from the important outcomes of this review. Lifestyle intervention versus control groupFor the mother:There was no clear evidence of a difference between lifestyle intervention and control groups for the risk of hypertensive disorders of pregnancy (pre-eclampsia) (average risk ratio (RR) 0.70; 95% confidence interval (CI) 0.40 to 1.22; four trials, 2796 women; I² = 79%, Tau² = 0.23; low-quality evidence); caesarean section (average RR 0.90; 95% CI 0.78 to 1.05; 10 trials, 3545 women; I² = 48%, Tau² = 0.02; low-quality evidence); development of type 2 diabetes (up to a maximum of 10 years follow-up) (RR 0.98, 95% CI 0.54 to 1.76; two trials, 486 women; I² = 16%; low-quality evidence); perineal trauma/tearing (RR 1.04, 95% CI 0.93 to 1.18; one trial, n = 1000 women; moderate-quality evidence) or induction of labour (average RR 1.20, 95% CI 0.99 to 1.46; four trials, n = 2699 women; I² = 37%; high-quality evidence).More women in the lifestyle intervention group had met postpartum weight goals one year after birth than in the control group (RR 1.75, 95% CI 1.05 to 2.90; 156 women; one trial, low-quality evidence). Lifestyle interventions were associated with a decrease in the risk of postnatal depression compared with the control group (RR 0.49, 95% CI 0.31 to 0.78; one trial, n = 573 women; low-quality evidence).For the infant/child/adult:Lifestyle interventions were associated with a reduction in the risk of being born large-for-gestational age (LGA) (RR 0.60, 95% CI 0.50 to 0.71; six trials, 2994 infants; I² = 4%; moderate-quality evidence). Birthweight and the incidence of macrosomia were lower in the lifestyle intervention group.Exposure to the lifestyle intervention was associated with decreased neonatal fat mass compared with the control group (mean difference (MD) -37.30 g, 95% CI -63.97 to -10.63; one trial, 958 infants; low-quality evidence). In childhood, there was no clear evidence of a difference between groups for body mass index (BMI) ≥ 85th percentile (RR 0.91, 95% CI 0.75 to 1.11; three trials, 767 children; I² = 4%; moderate-quality evidence).There was no clear evidence of a difference between lifestyle intervention and control groups for the risk of perinatal death (RR 0.09, 95% CI 0.01 to 1.70; two trials, 1988 infants; low-quality evidence). Of 1988 infants, only five events were reported in total in the control group and there were no events in the lifestyle group. There was no clear evidence of a difference between lifestyle intervention and control groups for a composite of serious infant outcome/s (average RR 0.57, 95% CI 0.21 to 1.55; two trials, 1930 infants; I² = 82%, Tau² = 0.44; very low-quality evidence) or neonatal hypoglycaemia (average RR 0.99, 95% CI 0.65 to 1.52; six trials, 3000 infants; I² = 48%, Tau² = 0.12; moderate-quality evidence). Diabetes and adiposity in adulthood and neurosensory disability in later childhoodwere not prespecified or reported as outcomes for any of the trials included in this review.

AUTHORS' CONCLUSIONS

Lifestyle interventions are the primary therapeutic strategy for women with GDM. Women receiving lifestyle interventions were less likely to have postnatal depression and were more likely to achieve postpartum weight goals. Exposure to lifestyle interventions was associated with a decreased risk of the baby being born LGA and decreased neonatal adiposity. Long-term maternal and childhood/adulthood outcomes were poorly reported.The value of lifestyle interventions in low-and middle-income countries or for different ethnicities remains unclear. The longer-term benefits or harms of lifestyle interventions remains unclear due to limited reporting.The contribution of individual components of lifestyle interventions could not be assessed. Ten per cent of participants also received some form of pharmacological therapy. Lifestyle interventions are useful as the primary therapeutic strategy and most commonly include healthy eating, physical activity and self-monitoring of blood glucose concentrations.Future research could focus on which specific interventions are most useful (as the sole intervention without pharmacological treatment), which health professionals should give them and the optimal format for providing the information. Evaluation of long-term outcomes for the mother and her child should be a priority when planning future trials. There has been no in-depth exploration of the costs 'saved' from reduction in risk of LGA/macrosomia and potential longer-term risks for the infants.

Different types of dietary advice for women with gestational diabetes mellitus

BACKGROUND

Dietary advice is the main strategy for managing gestational diabetes mellitus (GDM). It remains unclear what type of advice is best.

OBJECTIVES

To assess the effects of different types of dietary advice for women with GDM for improving health outcomes for women and babies.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (8 March 2016), PSANZ's Trials Registry (22 March 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials comparing the effects of different types of dietary advice for women with GDM.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study eligibility, risk of bias, and extracted data. Evidence quality for two comparisons was assessed using GRADE, for primary outcomes for the mother: hypertensive disorders of pregnancy; caesarean section; type 2 diabetes mellitus; and child: large-for-gestational age; perinatal mortality; neonatal mortality or morbidity composite; neurosensory disability; secondary outcomes for the mother: induction of labour; perineal trauma; postnatal depression; postnatal weight retention or return to pre-pregnancy weight; and child: hypoglycaemia; childhood/adulthood adiposity; childhood/adulthood type 2 diabetes mellitus.

MAIN RESULTS

In this update, we included 19 trials randomising 1398 women with GDM, at an overall unclear to moderate risk of bias (10 comparisons). For outcomes assessed using GRADE, downgrading was based on study limitations, imprecision and inconsistency. Where no findings are reported below for primary outcomes or pre-specified GRADE outcomes, no data were provided by included trials. Primary outcomes Low-moderate glycaemic index (GI) versus moderate-high GI diet (four trials): no clear differences observed for: large-for-gestational age (risk ratio (RR) 0.71, 95% confidence interval (CI) 0.22 to 2.34; two trials, 89 infants; low-quality evidence); severe hypertension or pre-eclampsia (RR 1.02, 95% CI 0.07 to 15.86; one trial, 95 women; very low-quality evidence); eclampsia (RR 0.34, 95% CI 0.01 to 8.14; one trial, 83 women; very low-quality evidence) or caesarean section (RR 0.66, 95% CI 0.29 to 1.47; one trial, 63 women; low-quality evidence). Energy-restricted versus no energy-restricted diet (three trials): no clear differences seen for: large-for-gestational age (RR 1.17, 95% CI 0.65 to 2.12; one trial, 123 infants; low-quality evidence); perinatal mortality (no events; two trials, 423 infants; low-quality evidence); pre-eclampsia (RR 1.00, 95% CI 0.51 to 1.97; one trial, 117 women; low-quality evidence); or caesarean section (RR 1.12, 95% CI 0.80 to 1.56; two trials, 420 women; low-quality evidence). DASH (Dietary Approaches to Stop Hypertension) diet versus control diet (three trials): no clear differences observed for: pre-eclampsia (RR 1.00, 95% CI 0.31 to 3.26; three trials, 136 women); however there were fewer caesarean sections in the DASH diet group (RR 0.53, 95% CI 0.37 to 0.76; two trials, 86 women). Low-carbohydrate versus high-carbohydrate diet (two trials): no clear differences seen for: large-for-gestational age (RR 0.51, 95% CI 0.13 to 1.95; one trial, 149 infants); perinatal mortality (RR 3.00, 95% CI 0.12 to 72.49; one trial, 150 infants); maternal hypertension (RR 0.40, 95% CI 0.13 to 1.22; one trial, 150 women); or caesarean section (RR 1.29, 95% CI 0.84 to 1.99; two trials, 179 women). High unsaturated fat versus low unsaturated fat diet (two trials): no clear differences observed for: large-for-gestational age (RR 0.54, 95% CI 0.21 to 1.37; one trial, 27 infants); pre-eclampsia (no cases; one trial, 27 women); hypertension in pregnancy (RR 0.54, 95% CI 0.06 to 5.26; one trial, 27 women); caesarean section (RR 1.08, 95% CI 0.07 to 15.50; one trial, 27 women); diabetes at one to two weeks (RR 2.00, 95% CI 0.45 to 8.94; one trial, 24 women) or four to 13 months postpartum (RR 1.00, 95% CI 0.10 to 9.61; one trial, six women). Low-GI versus high-fibre moderate-GI diet (one trial): no clear differences seen for: large-for-gestational age (RR 2.87, 95% CI 0.61 to 13.50; 92 infants); caesarean section (RR 1.91, 95% CI 0.91 to 4.03; 92 women); or type 2 diabetes at three months postpartum (RR 0.76, 95% CI 0.11 to 5.01; 58 women). Diet recommendation plus diet-related behavioural advice versus diet recommendation only (one trial): no clear differences observed for: large-for-gestational age (RR 0.73, 95% CI 0.25 to 2.14; 99 infants); or caesarean section (RR 0.78, 95% CI 0.38 to 1.62; 99 women). Soy protein-enriched versus no soy protein diet (one trial): no clear differences seen for: pre-eclampsia (RR 2.00, 95% CI 0.19 to 21.03; 68 women); or caesarean section (RR 1.00, 95% CI 0.57 to 1.77; 68 women). High-fibre versus standard-fibre diet (one trial): no primary outcomes reported. Ethnic-specific versus standard healthy diet (one trial): no clear differences observed for: large-for-gestational age (RR 0.14, 95% CI 0.01 to 2.45; 20 infants); neonatal composite adverse outcome (no events; 20 infants); gestational hypertension (RR 0.33, 95% CI 0.02 to 7.32; 20 women); or caesarean birth (RR 1.20, 95% CI 0.54 to 2.67; 20 women). Secondary outcomes For secondary outcomes assessed using GRADE no differences were observed: between a low-moderate and moderate-high GI diet for induction of labour (RR 0.88, 95% CI 0.33 to 2.34; one trial, 63 women; low-quality evidence); or an energy-restricted and no energy-restricted diet for induction of labour (RR 1.02, 95% CI 0.68 to 1.53; one trial, 114 women, low-quality evidence) and neonatal hypoglycaemia (average RR 1.06, 95% CI 0.48 to 2.32; two trials, 408 infants; very low-quality evidence).Few other clear differences were observed for reported outcomes. Longer-term health outcomes and health services use and costs were largely not reported.

AUTHORS' CONCLUSIONS

Evidence from 19 trials assessing different types of dietary advice for women with GDM suggests no clear differences for primary outcomes and secondary outcomes assessed using GRADE, except for a possible reduction in caesarean section for women receiving a DASH diet compared with a control diet. Few differences were observed for secondary outcomes.Current evidence is limited by the small number of trials in each comparison, small sample sizes, and variable methodological quality. More evidence is needed to assess the effects of different types of dietary advice for women with GDM. Future trials should be adequately powered to evaluate short- and long-term outcomes.