Comparative effectiveness of adjunct non-pharmacological interventions on maternal and neonatal outcomes in gestational diabetes mellitus patients: A systematic review and network meta-analysis protocol of randomized controlled trials.

BACKGROUND: Gestational diabetes mellitus (GDM) in pregnancy leads to a range of perinatal complications. Although several randomized controlled trials (RCT) have tested the effect of non-pharmacological standard GDM care adjuncts on these outcomes, there is no agglomerated statistical evidence on how their occurrence risk varies across interventions and with placebo. Therefore, a systematic review and network meta-analysis (NMA) protocol is proposed here to address this evidence gap. MATERIALS AND METHODS: A search for above RCTs published in the English language will transpire in PubMed, Embase, and Scopus databases irrespective of date and geographic boundary. The RCTs must test nutritional supplementation, digital intervention, structured exercise program, educational program, counseling service, or a combination of these prenatally in GDM patients. These should report ≥1 of the following outcomes- cesarean section, pre-eclampsia, polyhydramnios, preterm birth, macrosomia, prolonged labor, gestational hypertension, premature rupture of membranes, congenital anomaly, Apgar scores, birth weight, birth length, gestational age at birth, neonatal hypoglycemia, neonatal hyperbilirubinemia, and neonatal Corpulence Index. The risk of bias assessment of the recruited trials will transpire using the Revised Cochrane risk-of-bias tool. Determination of the comparative effectiveness between interventions will occur by the frequentist method NMA for respective outcomes. The categorical and continuous outcomes effect size will get calculated in risk ratio and weighted or standardized mean difference, respectively. For each NMA model, network maps and league tables will show the connections between interventions and effect sizes with their 95% confidence intervals for each intervention pair compared, respectively. The publication bias assessment will occur using comparison-adjusted funnel plots. Best intervention prediction for NMA models with statistically significant intervention effect will happen by determining the surface under the cumulative ranking curve values. Statistical analysis will ensue using Stata software (v16). The statistical significance estimation will happen at p<0.05 and 95% confidence interval. TRIAL REGISTRATION: PROSPERO registration no: CRD42021271199; https://clinicaltrials.gov/.

Study on the Effects of Individualized Nutritional Intervention on Pregnancy Outcome and Neonatal Immune Function in Patients with Gestational Diabetes Mellitus.

OBJECTIVE: To study the effects of individualized nutritional intervention on pregnancy outcome and neonatal immune function in patients with gestational diabetes mellitus (GDM). METHODS: A retrospective analysis was conducted on 100 GDM patients from the obstetrics and gynecology department of our institute between February 2019 and February 2020. The patients were allocated into the control group given regular intervention and the experimental group given individualized nutritional intervention according to different intervention measures, with 50 cases in each group. The comparison was carried out for patients in the two groups with regard to their modality of delivery, neonatal health, their plasma glucose in fasting state, 2 h after eating, and before bedtime; glycohemoglobin at 8 months of pregnancy, at 9 months of pregnancy, during labor, and 1 month after delivery; their complications; and neonatal CD3+, CD4+, and CD8+ levels. RESULTS: The experimental group outperformed the control group in terms of the spontaneous delivery rate, the number of healthy neonates, and neonatal CD3+, CD4+, and CD8+ levels (P < 0.05). The plasma glucose in fasting state, 2 h after eating, and before bedtime; the glycohemoglobin at 8 months of pregnancy, at 9 months of pregnancy, during labor, and 1 month after delivery; and the incidence of complications of the experimental group were significantly lower than those of the control group (P < 0.05). CONCLUSION: Individualized nutritional intervention increases the rate of spontaneous delivery in GDM patients, enhances neonatal immune function, stabilizes plasma glucose, and reduces complications.

Does a high dietary intake of resistant starch affect glycaemic control and alter the gut microbiome in women with gestational diabetes? A randomised control trial protocol.

BACKGROUND: Gestational Diabetes Mellitus (GDM) is prevalent with lasting health implications for the mother and offspring. Medical nutrition therapy is the foundation of GDM management yet achieving optimal glycaemic control often requires treatment with medications, like insulin. New dietary strategies to improve GDM management and outcomes are required. Gut dysbiosis is a feature of GDM pregnancies, therefore, dietary manipulation of the gut microbiota may offer a new avenue for management. Resistant starch is a fermentable dietary fibre known to alter the gut microbiota and enhance production of short-chain fatty acids. Evidence suggests that short-chain fatty acids improve glycaemia via multiple mechanisms, however, this has not been evaluated in GDM. METHODS: An open-label, parallel-group design study will investigate whether a high dietary resistant starch intake or resistant starch supplement improves glycaemic control and changes the gut microbiome compared with standard dietary advice in women with newly diagnosed GDM. Ninety women will be randomised to one of three groups - standard dietary treatment for GDM (Control), a high resistant starch diet or a high resistant starch diet plus a 16 g resistant starch supplement. Measurements taken at Baseline (24 to 30-weeks' gestation), Day 10 and Day 56 (approximately 36 weeks' gestation) will include fasting plasma glucose levels, microbial composition and short-chain fatty acid concentrations in stool, 3-day dietary intake records and bowel symptoms questionnaires. One-week post-natal data collection will include microbial composition and short-chain fatty acid concentrations of maternal and neonatal stools, microbial composition of breastmilk, birthweight, maternal and neonatal outcomes. Mixed model analysis of variance will assess change in glycaemia and permutation-based multivariate analysis of variance will assess changes in microbial composition within and between intervention groups. Distance-based linear modelling will identify correlation between change in stool microbiota, short-chain fatty acids and measures of glycaemia. DISCUSSION: To improve outcomes for GDM dyads, evaluation of a high dietary intake of resistant starch to improve glycaemia through the gut microbiome needs to be established. This will expand the dietary interventions available to manage GDM without medication. TRIAL REGISTRATION: Australian New Zealand Clinical Trial Registry, ACTRN12620000968976p . Registered 28 September 2020.

The effect of bedtime snacks on fasting blood glucose levels in gestational diabetes mellitus.

AIM: To investigate the effect of different bedtime snacks (higher carbohydrate versus lower carbohydrate versus no snack) on first morning fasting blood glucose levels (BGLs) in women with diet-controlled gestational diabetes mellitus (GDM) and borderline fasting glucose levels. METHODS: This prospective randomised crossover trial enrolled women with diet controlled GDM between 24 and 34 weeks gestation who had two or more first morning fasting BGLs between 4.7 and 5.4 mmol/L in the week prior to recruitment. The women were randomly allocated to 6 different orders of 5 days each of a standardised higher carbohydrate bedtime snack, a lower carbohydrate bedtime snack and no bedtime snack. The primary outcome was fasting capillary BGL as measured with a home glucometer, and the secondary outcome was requirement for insulin as assessed by a physician. RESULTS: A total of 68 women with GDM were enrolled in and completed the study at a median gestation of 30.8 weeks. Compared with no bedtime snack, the higher carbohydrate snack (4.96 vs 4.87 mmol/L, mean difference: 0.09 mmol/L, 95% CI 0.05-0.13, p < 0.001) and the lower carbohydrate snack (5.01 vs 4.87 mmol/L, mean difference: 0.14 mmol/L, 95% CI 0.09-0.18, p < 0.001) were both associated with a slightly higher fasting BGL the following morning. CONCLUSIONS: Taking a bedtime snack was associated with slightly higher fasting BGLs in women with diet-controlled GDM compared with no bedtime snack (Clinical trial registration: ACTRN12617000659303).

New Zealand women's experiences of managing gestational diabetes through diet: a qualitative study.

BACKGROUND: For women with gestational diabetes mellitus (GDM) poor dietary choices can have deleterious consequences for both themselves and their baby. Diet is a well-recognised primary strategy for the management of GDM. Women who develop GDM may receive dietary recommendations from a range of sources that may be inconsistent and are often faced with needing to make several dietary adaptations in a short period of time to achieve glycaemic control. The aim of this study was to explore how women diagnosed with GDM perceive dietary recommendations and how this information influences their dietary decisions during pregnancy and beyond. METHODS: Women diagnosed with GDM before 30 weeks' gestation were purposively recruited from two GDM clinics in Auckland, New Zealand. Data were generated using semi-structured interviews and thematic analysed to identify themes describing women's perceptions and experiences of dietary recommendations for the management of GDM. RESULTS: Eighteen women from a diverse range of sociodemographic backgrounds participated in the study. Three interconnected themes described women's perceptions of dietary recommendations and experiences in managing their GDM through diet: managing GDM is a balancing act; using the numbers as evidence, and the GDM timeframe. The primary objective of dietary advice was perceived to be to control blood glucose levels and this was central to each theme. Women faced a number of challenges in adhering to dietary recommendations. Their relationships with healthcare professionals played a significant role in their perception of advice and motivation to adhere to recommendations. Many women perceived the need to follow dietary recommendations to be temporary, with few planning to continue dietary adaptations long-term. CONCLUSIONS: The value of empathetic, individually tailored advice was highlighted in this study. A greater emphasis on establishing healthy dietary habits not just during pregnancy but for the long-term health of both mother and baby is needed.

An Update of Medical Nutrition Therapy in Gestational Diabetes Mellitus.

Gestational diabetes mellitus (GDM) is a serious and frequent pregnancy complication that can lead to short and long-term risks for both mother and fetus. Different health organizations proposed different algorithms for the screening, diagnosis, and management of GDM. Medical Nutrition Therapy (MNT), together with physical exercise and frequent self-monitoring, represents the milestone for GDM treatment in order to reduce maternal and fetal complications. The pregnant woman should benefit from her family support and make changes in their lifestyles, changes that, in the end, will be beneficial for the whole family. The aim of this manuscript is to review the literature about the Medical Nutrition Therapy in GDM and its crucial role in GDM management.

The Carbohydrate Threshold in Pregnancy and Gestational Diabetes: How Low Can We Go?

The original nutrition approach for the treatment of gestational diabetes mellitus (GDM) was to reduce total carbohydrate intake to 33-40% of total energy (EI) to decrease fetal overgrowth. Conversely, accumulating evidence suggests that higher carbohydrate intakes (60-70% EI, higher quality carbohydrates with low glycemic index/low added sugars) can control maternal glycemia. The Institute of Medicine (IOM) recommends ≥175 g/d of carbohydrate intake during pregnancy; however, many women are consuming lower carbohydrate (LC) diets (<175 g/d of carbohydrate or <40% of EI) within pregnancy and the periconceptual period aiming to improve glycemic control and pregnancy outcomes. This report systematically evaluates recent data (2018-2020) to identify the LC threshold in pregnancy in relation to safety considerations. Evidence from 11 reports suggests an optimal carbohydrate range of 47-70% EI supports normal fetal growth; higher than the conventionally recognized LC threshold. However, inadequate total maternal EI, which independently slows fetal growth was a frequent confounder across studies. Effects of a carbohydrate intake <175 g/d on maternal ketonemia and plasma triglyceride/free fatty acid concentrations remain unclear. A recent randomized controlled trial (RCT) suggests a higher risk for micronutrient deficiency with carbohydrate intake ≤165 g/d in GDM. Well-controlled prospective RCTs comparing LC (<165 g/d) and higher carbohydrate energy-balanced diets in pregnant women are clearly overdue.

A Glimpse at the Size of the Fetal Liver-Is It Connected with the Evolution of Gestational Diabetes?

Gestational diabetes mellitus (GDM) is defined as an impairment of glucose tolerance, manifested by hyperglycemia, which occurs at any stage of pregnancy. GDM is more common in the third trimester of pregnancy and usually disappears after birth. It was hypothesized that the glycemic status of the mother can modulate liver development and growth early during the pregnancy. The simplest modality to monitor the evolution of GDM employs noninvasive techniques. In this category, routinely obstetrical ultrasound (OUS) examinations (simple or 2D/3D) can be employed for specific fetal measurements, such as fetal liver length (FLL) or volume (FLV). FLL and FLV may emerge as possible predictors of GDM as they positively relate to the maternal glycated hemoglobin (HbA1c) levels and to the results of the oral glucose tolerance test. The aim of this review is to offer insight into the relationship between GDM and fetal nutritional status. Risk factors for GDM and the short- and long-term outcomes of GDM pregnancies are also discussed, as well as the significance of different dietary patterns. Moreover, the review aims to fill one gap in the literature, investigating whether fetal liver growth can be used as a predictor of GDM evolution. To conclude, although studies pointed out a connection between fetal indices and GDM as useful tools in the early detection of GDM (before 23 weeks of gestation), additional research is needed to properly manage GDM and offspring health.

TIMER: A Clinical Study of Energy Restriction in Women with Gestational Diabetes Mellitus.

Medical nutrition therapy is an integral part of gestational diabetes mellitus (GDM) management; however, the prescription of optimal energy intake is often a difficult task due to the limited available evidence. The present pilot, feasibility, parallel, open-label and non-randomized study aimed to evaluate the effect of a very low energy diet (VLED, 1600 kcal/day), or a low energy diet (LED, 1800 kcal/day), with or without personalized exercise sessions, among women with GDM in singleton pregnancies. A total of 43 women were allocated to one of four interventions at GDM diagnosis: (1) VLED (n = 15), (2) VLED + exercise (n = 4), (3) LED (n = 16) or (4) LED + exercise (n = 8). Primary outcomes were gestational weight gain (GWG), infant birth weight, complications at delivery and a composite outcomes score. Secondary outcomes included type of delivery, prematurity, small- for-gestational-age (SGA) or large-for-gestational-age (LGA) infants, macrosomia, Apgar score, insulin use, depression, respiratory quotient (RQ), resting metabolic rate (RMR) and middle-upper arm circumference (MUAC). GWG differed between intervention groups (LED median: 12.0 kg; VLED: 5.9 kg). No differences were noted in the type of delivery, infant birth weight, composite score, prevalence of prematurity, depression, RQ, Apgar score, MUAC, or insulin use among the four groups. Regarding components of the composite score, most infants (88.4%) were appropriate-for-gestational age (AGA) and born at a gestational age of 37-42 weeks (95.3%). With respect to the mothers, 9.3% experienced complications at delivery, with the majority being allocated at the VLED + exercise arm (p < 0.03). The composite score was low (range 0-2.5) for all mother-infant pairs, indicating a "risk-free" pregnancy outcome. The results indicate that adherence to a LED or VLED induces similar maternal, infant and obstetrics outcomes.

Effect of an individualised nutritional intervention on gestational diabetes mellitus prevention in a high-risk population screened by a prediction model: study protocol for a multicentre randomised controlled trial.

BACKGROUND: The ability of a preventive nutritional intervention to reduce the morbidity of gestational diabetes mellitus (GDM) remains controversial. We aim to assess whether GDM can be prevented by an individualised nutritional intervention in pregnant women who are at high risk for the disease based on a prediction model. METHODS/DESIGN: A multicentre randomised controlled trial was designed to assess the efficacy of an individualised nutritional intervention for the prevention of GDM in a high-risk population screened by a novel prediction model in the first trimester. Pregnant women evaluated to be at high risk for GDM by the prediction model at less than 14 gestational weeks will be included. Women with pre-existing chronic diseases, including pregestational diabetes, or who are currently prescribed medicines that affect glucose values will be excluded. Allocation to intervention/control at a ratio of 1:1 will be conducted by a computerized randomisation system. The intervention group will complete 3-day food records and receive 3 individualised nutritional consultations with professional dieticians before the oral glucose tolerance test. The primary intention of the intervention is to promote a long-term healthy dietary pattern and prevent excessive gestational weight gain throughout pregnancy. The control group will complete 3-day food records at designated gestational weeks and receive standard antenatal care according to local health care provisions. The primary outcome is the incidence of GDM according to the criteria of the International Association of Diabetes and Pregnancy Study Group (IADPSG). A sample of 464 participants will provide 80% power to detect a 30% reduction in GDM incidence (α = 0.05 two tailed, 10% dropout). A total of 500 participants will be recruited. DISCUSSION: To date, this is the first randomised controlled trial aimed to evaluate the protective effect of an individualised nutritional intervention against GDM based on a logistic regression prediction model. Eligibility is not limited to obese women or singleton pregnancies, as in previous studies. This pragmatic trial is expected to provide valuable information on early screening and effective GDM prevention methods. TRIAL REGISTRATION NUMBER: ChiCTR, ChiCTR1900026963 . Registered 27 October 2019.

The effect of probiotic supplementation on the risk of gestational diabetes mellitus among high-risk pregnant women: A parallel double-blind, randomized, placebo-controlled clinical trial.

BACKGROUND: Based on a comprehensive search, we realized that the findings of the available literature are contradictory, and also limited data are available on Middle Eastern populations in terms of probiotic supplementation during the pregnancy. Therefore, the current double-blind, randomized, placebo-controlled clinical trial was carried out to investigate the effects of probiotic supplementation during pregnancy on the risk of gestational diabetes mellitus and also other maternal and neonatal outcomes. MATERIALS AND METHODS: The pregnant women were randomized to either received probiotic supplement (n = 271) or placebo (n = 271) from the first half of the second trimester (14 weeks of pregnancy) up to 24 weeks when pregnant women routinely evaluated regarding the GDM. During the 24-28 weeks of pregnancy, mothers were evaluated regarding the presence of GDM using a 75 g oral glucose tolerance test (OGTT). The fasting blood glucose (FBG) was also evaluated within OGTT processes. Each 500 mg probiotic capsule was a mixture of Lactobacillus acidophilus LA1 (>7.5 × 109 CFU), Bifidobacterium longum sp54 cs (>1.5 × 109 CFU), and Bifidobacterium bifidum sp9 cs (>6 × 109 CFU). RESULTS: Overall, 507 pregnant women make up our study population with a mean age of 32.03 years and a Body Mass Index (BMI) of 30.20 kg/m2. There was no significant difference between the intervention and the control group regarding FBG (88.68 vs. 89.61 mg/dL; P = 0.338), OGTT-1h (163.86 vs. 166.88; mg/dL; P = 0.116), and OGTT-2h (138.39 vs. 139.27; mg/dL; P = 0.599). The incidence of GDM in the intervention group was 41.9% which was not significantly different from the control group (40.2%) (P = 0.780). Likewise, no significant difference was detected in terms of other studied parameters. CONCLUSIONS: It seems that probiotics supplementation of pregnant women from the first half of the second trimester up to 24 weeks of pregnancy does not reduce the risk of GDM, or improve other neonatal and maternal outcomes.

Sociodemographic Factors Associated with Adherence to Dietary Guidelines in Women with Gestational Diabetes: A Cohort Study.

Dietary advice is the cornerstone of care for women with gestational diabetes mellitus (GDM). However, adherence to this advice is variable. We aimed to identify the proportion of women with GDM who adhere to the New Zealand nutrition guideline recommendations and assess the sociodemographic factors linked to dietary adherence. We assessed dietary intake at 36 weeks' gestation in a cohort of 313 women with GDM and compared this with the dietary recommendations for the management of GDM. Associations between maternal characteristics and dietary adherence were assessed using ANOVA, chi square, logistic regression, and linear regression tests. Women with GDM had an average adherence score of 6.17 out of 10 to dietary recommendations, but no one adhered to all the recommendations. Adherence to recommendations was lowest for saturated fat, and wholegrain breads and cereals. While 85% visited a dietitian, only 28% of women achieved their recommended weight gain. Maternal factors associated with lower dietary adherence were primiparity, no previous history of GDM, being underweight, and smoking. Adherence to the dietary recommendations by women with GDM in New Zealand for the management could be improved. Further research is needed to identify ways for women with GDM to improve their dietary adherence.

Whey protein preloading can alleviate stress adaptation disorder and improve hyperglycemia in women with gestational diabetes mellitus.

AIMS: To investigate the change of stress hormones, oxidative stress and insulin resistance (IR) in women with gestational diabetes mellitus (GDM) after supplement whey protein, in an attempt to gain insights into the prevention and treatment of GDM. MATERIALS AND METHODS: 60 GDM women were recruited in this study, and 30 women received a preload drink containing 20 g whey protein as group GDM-W, and the other 30 women received control flavoring drink as group GDM, and the trial lasted for 14 days. Plasma epinephrine (E), noradrenaline (NE), and cortisol were detected; we also determined levels of malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione (GSH). Homeostasis model assessment of insulin resistance (HOMA-IR) was used to assess IR. RESULTS: In the GDM-W group, postprandial blood glucose was decreased significantly on 3, 5, 7, and 14 days (all p < .05), plasma 2 h insulin was increased by 7.2, 8.6, and 20.5% on days 5, 7, and 14 (p < .05, .05, .01). HOMA-IR was decreased significantly on day 14 (p < .05). MDA was decreased by 20.7% on day 14 (p < .01), and anti-oxidative enzymes' SOD was decreased by 13.4% on day 14 (p < .05) and GSH was decreased by 16.7 and 29.1% on days 7 and 14 (both p < .05). Stress hormones E and cortisol were decreased by 10.8 and 19.8%, respectively, on day 14 (p < .05). There was no significant difference in NE between the two groups within 14 days. CONCLUSIONS: Whey protein supplementation may improve hyperglycemia by alleviating stress disorder and oxidative stress injury in GDM women. This trial was registered at chictr.org.cn/as ChiCTR1800020413.

The effects of vitamin and mineral supplementation on women with gestational diabetes mellitus.

BACKGROUND: The effects of vitamin and mineral supplementation on women with gestational diabetes mellitus (GDM) have not been well established. We conduct a meta-analysis to evaluate the effects of vitamin and mineral supplementation on glycemic control, inflammation and oxidative stress for women with GDM. METHODS: A systematic search of randomized controlled trials (RCTs) was conducted from PubMed, Embase, Web of Science and Cochrane Library up to July, 2020. Various results were pooled by using Review manager 5.3 and Stata 12.0. Mean difference (MD) with 95% confidence interval (CI) was estimated. Heterogeneity between studies was assessed by I-squared (I2) tests. RESULTS: Six hundred ninety-eight patients from 12 trials were included in our meta-analysis. Magnesium, zinc, selenium, calcium, vitamin D and E (alone or in combination) were found to significantly improve glycemic control in women with GDM compared to those receiving placebos: fasting plasma glucose (FPG) (MD = - 9.02; 95% CI: - 12.09, - 5.96; P < 0.00001), serum insulin (MD = - 4.33; 95% CI: - 5.35, - 3.32; P < 0.00001), homeostasis model assessment-insulin resistance (HOMA-IR) (MD = - 1.34; 95% CI: - 1.60, - 1.07; P < 0.00001), and homeostasis model of assessment for ß cell function (HOMA-B) (MD = - 15.58; 95% CI: - 23.70, - 7.46; P = 0.0002). Vitamin and mineral supplementation was found to attenuated inflammation and oxidative stress through decreasing high-sensitivity C-reactive protein (hs-CRP) (MD = - 1.29; 95% CI: - 1.82, - 0.76; P < 0.00001), malondialdehyde (MDA) (MD = - 0.71; 95% CI: - 0.97, - 0.45; P < 0.00001), and increasing total antioxidant capacity (TAC) (MD = 45.55; 95% CI: 22.02, 69.08; P = 0.0001). CONCLUSIONS: This meta-analysis shows that vitamin and mineral supplementation significantly improved glycemic control, attenuated inflammation and oxidative stress in women with GDM.

Effects of vitamin and omega-3 fatty acid co-supplementation on blood glucose in women with gestational diabetes mellitus: A protocol for systematic review and meta analysis.

BACKGROUND: There is limited study that has conducted a review investigating the clinical effects of vitamin and omega-3 fatty acid co-supplementation on blood glucose in women with gestational diabetes mellitus (GDM). Therefore, in order to provide new evidence-based medical evidence for clinical treatment, we undertook a systematic review and meta-analysis to assess the effectiveness and safety of vitamin and omega-3 fatty acid co-supplementation on blood glucose in women with GDM. METHODS: This protocol was written following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) statement guidelines. We will conduct systematic reviews and meta-analyses to identify relevant randomized controlled trials (RCTs) involving vitamin and omega-3 fatty acid co-supplementation on GDM in electronic databases including PubMed, Web of Science, Embase, and the Cochrane Library up to June 2021. Exclusion criteria include observational studies, non-RCTs, review articles, studies with a sample size <50, and studies with insufficient outcome data. The primary outcomes include fasting glucose and insulin. Secondary outcomes are evaluated in a homeostasis model of insulin resistance, total antioxidant capacity, triglycerides, total cholesterol, low-density lipoprotein cholesterol, preterm birth and macrosomia over 4 kg. RESULTS: The review will add to the existing literature by showing compelling evidence and improved guidance in clinic settings. REGISTRATION NUMBER: 10.17605/OSF.IO/NSW54.

Maternal and neonatal outcomes after energy-restricted diet for women with gestational diabetes mellitus: A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Gestational diabetes mellitus (GDM) affects 1% to 14% of pregnant women annually worldwide and is one of the most common pregnancy complications. OBJECTIVE: We reviewed studies on maternal and neonatal outcomes after dietary managements for women with GDM comparing caloric-restricted (intervention group) and unrestricted diets (control group). METHODS: We systematically searched online databases including Medline, Cochrane Controlled Register of Trials (CENTRAL), ScienceDirect, and Google Scholar from inception until September 2019. We performed a meta-analysis with random-effects model and reported pooled risk ratios (RRs) or pooled mean differences (MD) with 95% confidence intervals (CIs). RESULTS: We analyzed data from 6 randomized controlled trials including 1300 participants, most of them with high bias risks. We found that the women in the intervention group achieved slightly better glycemic control (pooled MD, -0.72 mg/dL; 95% CI, -7.10 to 5.66 mg/dL) and overall pregnancy outcomes (except neonatal hypoglycemia) than the women in the control group. CONCLUSION: An energy-restricted diet does not seem superior to the usual/standard GDM diet based on maternal or neonatal outcomes. But, clinical recommendations cannot be made as the evidence is inconclusive.

The effect of oat bran consumption on gestational diabetes: a randomized controlled clinical trial.

BACKGROUND: Gestational diabetes is the most common medical complication in pregnancy, and it has many side effects for the mother and the fetus. The aim of this study was to evaluate the effect of oat bran consumption on gestational diabetes. METHODS: This study is a randomized clinical trial that was performed on 112 women with gestational diabetes treated with diet. Participants were randomly divided into two groups of 56. Participants in both groups were given a diet for gestational diabetes. In addition to the diet, the intervention group received 30 g of oat bran daily for 4 weeks at lunch and dinner. Tests of fasting blood glucose and two-hour postprandial (2hpp) glucose were taken from both groups: before the intervention, and 2 and 4 weeks after the start of the intervention. Data analysis was performed using SPSS statistical software (version 22) using independent t-test, as well as Chi-square and Mann-Whitney tests. P values less than 0.05 were considered statistically significant. RESULTS: There was no statistically significant difference between the two groups in terms of mean blood glucose before the intervention, while 2 and 4 weeks after the intervention, mean fasting blood glucose and two-hour postprandial (2hpp) glucose decreased significantly in the intervention group compared with the control group (P < 0.001). CONCLUSION: Based on the results of this study, the addition of oat bran to the standard diet for pregnant women with gestational diabetes reduced fasting blood glucose and two-hour postprandial (2hpp) glucose. More detailed studies with higher sample sizes are recommended to prove the effectiveness of this valuable dietary supplement. TRIAL REGISTRATION: IRCT registration number: IRCT20191220045828N1 . Registration date: 2020-04-18. Registered while recruiting.

Dietary recommendations for women with gestational diabetes mellitus: a systematic review of clinical practice guidelines.

CONTEXT: Dietary advice is the cornerstone of care for women with gestational diabetes mellitus (GDM) to improve maternal and infant health. OBJECTIVES: This study aimed to compare dietary recommendations made in clinical practice guidelines (CPGs) for the management of GDM, evaluate their evidence base, identify research gaps, and assess CPG quality. The PRISMA guidelines were used. DATA SOURCES: Six databases were searched for CPGs, published between 2000 and 2019, that included dietary advice for the management of GDM. DATA EXTRACTION: Two reviewers independently assessed CPG quality (using the AGREE II tool) with respect to dietary recommendations (their strength, evidence base, and research gaps). DATA ANALYSIS: Of the 31 CPGs, 68% were assessed as low quality, mainly due to lack of editorial independence. Dietary advice was recommended as the first-line treatment by all CPGs, although the dietary recommendations themselves varied and sometimes were contradictory. Most dietary recommendations were strongly made (70%), but they were often based on very low-quality (54%), or low-quality (15%) evidence. Research gaps were identified for all diet-related recommendations. CONCLUSION: High-quality research is needed to improve the evidence base and address the research gaps identified. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration no. CRD42019147848.

Prophylactic metformin after antenatal corticosteroids (PROMAC): a double blind randomized controlled trial.

BACKGROUND: Antenatal corticosteroids (ACS) are increasingly used to improve prematurity-related neonatal outcome. A recognized and common adverse effect from administration of antenatal corticosteroid is maternal hyperglycemia. Even normal pregnancy is characterized by relative insulin resistance and glucose intolerance. Treatment of maternal hyperglycemia after ACS might be indicated due to the higher risk of neonatal acidosis which may coincide with premature birth. Metformin is increasingly used to manage diabetes mellitus during pregnancy as it is effective and more patient friendly. There is no data on prophylactic metformin to maintain euglycemia following antenatal corticosteroids administration. METHODS: A double blind randomized trial. 103 women scheduled to receive two doses of 12-mg intramuscular dexamethasone 12-hour apart were separately randomized to take prophylactic metformin or placebo after stratification according to their gestational diabetes (GDM) status. First oral dose of allocated study drug was taken at enrolment and continued 500 mg twice daily for 72 hours if not delivered. Six-point blood sugar profiles were obtained each day (pre- and two-hour post breakfast, lunch and dinner) for up to three consecutive days. A hyperglycemic episode is defined as capillary glucose fasting/pre-meal ≥ 5.3 mmol/L or two-hour post prandial/meal ≥ 6.7 mmol/L. Primary outcome was hyperglycemic episodes on Day-1 (first six blood sugar profile points) following antenatal corticosteroids. RESULTS: Number of hyperglycemic episodes on the first day were not significantly different (mean ± standard deviation) 3.9 ± 1.4 (metformin) vs. 4.1 ± 1.6 (placebo) p = 0.64. Hyperglycemic episodes markedly reduced on second day in both arms to 0.9 ± 1.0 (metformin) vs. 1.2 ± 1.0 (placebo) p = 0.15 and further reduced to 0.6 ± 1.0 (metformin) vs. 0.7 ± 1.0 (placebo) p = 0.67 on third day. Hypoglycemic episodes during the 3-day study period were few and all other secondary outcomes were not significantly different. CONCLUSIONS: In euglycemic and diet controllable gestational diabetes mellitus women, antenatal corticosteroids cause sustained maternal hyperglycemia only on Day-1. The magnitude of Day-1 hyperglycemia is generally low. Prophylactic metformin does not reduce antenatal corticosteroids' hyperglycemic effect. TRIAL REGISTRATION: The trial is registered in the ISRCTN registry on May 4 2017 with trial identifier https://doi.org/10.1186/ISRCTN10156101 .