Pregnancy and Glycemic Index Outcomes study: effects of low glycemic index compared with conventional dietary advice on selected pregnancy outcomes

Maternal Dietary Glycemic Index and Glycemic Load in Pregnancy and Offspring Cord Blood DNA Methylation

OBJECTIVE

Suboptimal nutrition in pregnancy is associated with worse offspring cardiometabolic health. DNA methylation may be an underlying mechanism. We meta-analyzed epigenome-wide association studies (EWAS) of maternal dietary glycemic index and load with cord blood DNA methylation.

RESEARCH DESIGN AND METHODS

We calculated maternal glycemic index and load from food frequency questionnaires and ran EWAS on cord blood DNA methylation in 2,003 mother-offspring pairs from three cohorts. Analyses were additionally stratified by maternal BMI categories. We looked-up the findings in EWAS of maternal glycemic traits and BMI as well as in EWAS of birth weight and child BMI. We examined associations with gene expression in child blood in the online Human Early Life Exposome eQTM catalog and in 223 adipose tissue samples.

RESULTS

Maternal glycemic index and load were associated with cord blood DNA methylation at 41 cytosine-phosphate-guanine sites (CpGs, P < 1.17 × 10-7), mostly in mothers with overweight/obesity. We did not observe overlap with CpGs associated with maternal glycemic traits, BMI, or child birth weight or BMI. Only DNA methylation at cg24458009 and cg23347399 was associated with expression of PCED1B and PCDHG, respectively, in child blood, and DNA methylation at cg27193519 was associated with expression of TFAP4, ZNF500, PPL, and ANKS3 in child subcutaneous adipose tissue.

CONCLUSIONS

We observed multiple associations of maternal glycemic index and load during pregnancy with cord blood DNA methylation, mostly in mothers with overweight/obesity; some of these CpGs were associated with gene expression. Additional studies are required to further explore functionality, uncover causality, and study pathways to offspring health.

Food taboos during pregnancy: meta-analysis on cross cultural differences suggests specific, diet-related pressures on childbirth among agriculturalists

Pregnancy is the most delicate stage of human life history as well as a common target of food taboos across cultures. Despite puzzling evidence that many pregnant women across the world reduce their intake of nutritious foods to accomplish cultural norms, no study has provided statistical analysis of cross-cultural variation in food taboos during pregnancy. Moreover, antenatal practices among forager and agriculturalists have never been compared, despite subsistence mode being known to affect staple foods and lifestyle directly. This gap hinders to us from understanding the overall threats attributed to pregnancy, and their perceived nutritional causes around the world. The present study constitutes the first cross-cultural meta-analysis on food taboos during pregnancy. We examined thirty-two articles on dietary antenatal restrictions among agricultural and non-agricultural societies, in order to: (i) identify cross-culturally targeted animal, plant and miscellaneous foods; (ii) define major clusters of taboo focus; (iii) test the hypothesis that food types and clusters of focus distribute differently between agricultural and non-agricultural taboos; and (iv) test the hypothesis that food types distribute differently across the clusters of taboo focus. All data were analysed in SPSS and RStudio using chi-squared tests and Fisher's exact tests. We detected a gradient in taboo focus that ranged from no direct physiological interest to the fear of varied physiological complications to a very specific concern over increased birth weight and difficult delivery. Non-agricultural taboos were more likely to target non-domesticated animal foods and to be justified by concerns not directly linked to the physiological sphere, whereas agricultural taboos tended to targed more cultivated and processed products and showed a stronger association with concerns over increased birth weight. Despite some methodological discrepancies in the existing literature on food taboos during pregnancy, our results illustrate that such cultural traits are useful for detecting perception of biological pressures on reproduction across cultures. Indeed, the widespread concern over birth weight and carbohydrate rich foods overlaps with clinical evidence that obstructed labor is a major threat to maternal life in Africa, Asia and Eurasia. Furthermore, asymmetry in the frequency of such concern across subsistence modes aligns with the evolutionary perspective that agriculture may have exacerbated delivery complications. This study highlights the need for the improved understanding of dietary behaviors during pregnancy across the world, addressing the role of obstructed labor as a key point of convergence between clinical, evolutionary and cultural issues in human behavior.

Maternal Dietary Quality and Dietary Inflammation Associations with Offspring Growth, Placental Development, and DNA Methylation

The ‘Developmental Origins of Health and Diseases’ hypothesis posits that prenatal maternal diet influences offspring growth and later life health outcomes. Dietary assessment has focused on selected nutrients. However, this approach does not consider the complex interactions between foods and nutrients. To provide a more comprehensive approach to public health, dietary indices have been developed to assess dietary quality, dietary inflammation and risk factors for non-communicable diseases. Thus far, their use in the context of placental development is limited and associations with offspring outcomes have been inconsistent. Although epidemiological studies have focused on the role of maternal diet on foetal programming, the underlying mechanisms are still poorly understood. Some evidence suggests these associations may be driven by placental and epigenetic changes. In this narrative review, we examine the current literature regarding relationships between key validated diet quality scores (Dietary Inflammatory Index [DII], Mediterranean diet [MD], Healthy Eating Index [HEI], Alternative Healthy Eating Index [AHEI], Dietary Approaches to Stop Hypertension [DASH], Glycaemic Index [GI] and Glycaemic Load [GL]) in pregnancy and birth and long-term offspring outcomes. We summarise findings, discuss potential underlying placental and epigenetic mechanisms, in particular DNA methylation, and highlight the need for further research and public health strategies that incorporate diet quality and epigenetics.

Obesity in Pregnancy: ACOG Practice Bulletin, Number 230

Obstetrician-gynecologists are the leading experts in the health care of women, and obesity is the most common medical condition in women of reproductive age. Obesity in women is such a common condition that the implications relative to pregnancy often are unrecognized, overlooked, or ignored because of the lack of specific evidence-based treatment options. The management of obesity requires long-term approaches ranging from population-based public health and economic initiatives to individual nutritional, behavioral, or surgical interventions. Therefore, an understanding of the management of obesity during pregnancy is essential, and management should begin before pregnancy and continue through the postpartum period. Although the care of the obese woman during pregnancy requires the involvement of the obstetrician or other obstetric care professional, additional health care professionals, such as nutritionists, can offer specific expertise related to management depending on the comfort level of the obstetric care professional. The purpose of this Practice Bulletin is to offer an integrated approach to the management of obesity in women of reproductive age who are planning a pregnancy.

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.

The Impact of an Early Lifestyle Intervention on Pregnancy Outcomes in a Cohort of Insulin-Resistant Overweight and Obese Women

Obese women are more likely to have decreased insulin sensitivity and are at increased risk for many adverse pregnancy outcomes. An early lifestyle intervention (LI) may have the potential to reduce the impact of insulin resistance (IR) on perinatal outcomes. We report post hoc analysis of an open-label randomized control trial that includes IR women with body-mass index ≥25 randomly assigned to a LI with a customized low glycemic index diet or to standard care (SC) involving generic counseling about healthy diet and physical activity. Women were evaluated at 16, 20, 28, and 36 weeks of gestation, at which times perinatal outcomes were collected and analyzed. An oral-glucose-tolerance test (OGTT) showed that women in the LI group had lower plasma glucose levels at 120 min at 16-18 weeks of gestation, and at 60 and 120 min at 24-28 weeks. More importantly, these women had a lower rate of large-for-gestational-age (LGA) infants (p = 0.04). Interestingly, the caloric restriction and low-glycemic index diet did not increase the rate of small-for-gestational-age (SGA) babies in the LI group. A lifestyle intervention started early in pregnancy on overweight and obese women had the potential to restore adequate glucose tolerance and mitigate the detrimental role of IR on neonatal outcomes, especially on fetal growth.

The association of dietary glycaemic index and glycaemic load with gestational weight gain and newborn birth weight

Diet during pregnancy is related to several maternal and infant health outcomes; however, the relationship between maternal dietary glycaemic index (GI) and glycaemic load (GL) and gestational weight gain (GWG) or newborn birth weight is controversial. The purpose of the present study was to investigate the relationship between maternal dietary GI and GL and GWG and birth weight. A cohort of adult pregnant women with usual obstetric risk was followed in Botucatu, SP, Brazil. Two 24-h dietary recalls were collected in each gestational trimester (<14, 24-27, 31-34 weeks), one in person and the other by telephone. GI and GL were determined using the software Nutrition Data System for Research. GWG was obtained from medical records and evaluated as the weekly GWG between the second and third gestational trimesters. Newborn birth weight z-score in relation to gestational age was evaluated according to Intergrowth-21st Project recommendations. A multiple linear regression model, adjusted for potential confounders, showed a one-point increase in the GI resulted in a mean decrease of 12·9 (95 % CI -21·48, -4·24) g in weekly GWG; GL was not associated with this outcome. The birth weight z-score was not associated with GI (P = 0·763) or GL (P = 0·317). In conclusion, in a cohort of pregnant women considered at usual risk for obstetric complications, maternal dietary GI was negatively associated with weekly GWG in the second and third gestational trimesters. No association was observed between GL and GWG, and neither GI nor GL was associated with birth weight z-score.

Variation in outcome reporting in randomized controlled trials of interventions for prevention and treatment of fetal growth restriction

OBJECTIVE

Although fetal growth restriction (FGR) is well known to be associated with adverse outcomes for the mother and offspring, effective interventions for the management of FGR are yet to be established. Trials reporting interventions for the prevention and treatment of FGR may be limited by heterogeneity in the underlying pathophysiology. The aim of this study was to conduct a systematic review of outcomes reported in randomized controlled trials (RCTs) assessing interventions for the prevention or treatment of FGR, in order to identify and categorize the variation in outcome reporting.

METHODS

MEDLINE, EMBASE and The Cochrane Library were searched from inception until August 2018 for RCTs investigating therapies for the prevention and treatment of FGR. Studies were assessed systematically and data on outcomes that were reported in the included studies were extracted and categorized. The methodological quality of the included studies was assessed using the Jadad score.

RESULTS

The search identified 2609 citations, of which 153 were selected for full-text review and 72 studies (68 trials) were included in the final analysis. There were 44 trials relating to the prevention of FGR and 24 trials investigating interventions for the treatment of FGR. The mean Jadad score of all studies was 3.07, and only nine of them received a score of 5. We identified 238 outcomes across the included studies. The most commonly reported were birth weight (88.2%), gestational age at birth (72.1%) and small-for-gestational age (67.6%). Few studies reported on any measure of neonatal morbidity (27.9%), while adverse effects of the interventions were reported in only 17.6% of trials.

CONCLUSIONS

There is significant variation in outcome reporting across RCTs of therapies for the prevention and treatment of FGR. The clinical applicability of future research would be enhanced by the development of a core outcome set for use in future trials. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Effectiveness of an Intervention of Dietary Counseling for Overweight and Obese Pregnant Women in the Consumption of Sugars and Energy

Objective: Evaluate if an intervention based on nutritional counseling decreases total sugars and energy consumption in overweight and obese pregnant women, compared to their previous consumption and compared to women who only received routine counseling. Methods: Randomized study of two groups: dietary counseling (Intervention Group: IG) and routine counseling (Control Group: CG). The intervention consisted of three educational sessions focused on decreasing intake of foods that most contribute to sugars consumption. Changes in sugars and energy consumption were evaluated by a food frequency questionnaire before and after the intervention. Results: We evaluated 433 pregnant women, 272 in IG and 161 in CG, who before intervention had a mean consumption of 140 g total sugars and 2134 kcal energy per day. At the end of the intervention, the IG showed 15 g/day lower consumption of total sugars (95% CI: −25 and −5 g/day), 2% less total energy from sugars (95% CI: −3% and −1% g/day), and 125 kcal/day less energy than the CG (95% CI: −239 and −10 kcal/day). Table sugar, sweets, and soft drinks had the greatest reduction in consumption. Conclusions: The intervention focused on counseling on the decrease in consumption of the foods that most contribute to sugars consumption in overweight and obese pregnant women was effective in decreasing total sugars and energy consumption, mainly in the food groups high in sugars. Future studies should examine if this intervention has an effect on maternal and fetal outcomes.

How diet, physical activity and psychosocial well-being interact in women with gestational diabetes mellitus: an integrative review

Background

Gestational Diabetes Mellitus (GDM) is associated with future cardio-metabolic risks for the mother and her child. In addition, one-third of women with recent GDM develop postpartum depression. Given these adverse impacts of GDM on the health of the mother and her offspring, it is important to intervene on modifiable factors, such as diet, physical activity, and psychosocial well-being. This integrative review therefore explored evidence on how these modifiable factors interact in women with GDM and their offspring, and how effective combined interventions are on reducing adverse impacts of GDM.

Methods

A comprehensive search strategy included carefully selected terms that corresponded to the domains of interest (diet, physical activity and psychosocial well-being). The databases searched for articles published between 1980 and February 2018 were: CINAHL, PsycINFO, Embase, Pubmed and Cochrane. Studies that were included in this review were either observational or intervention studies that included at least two domains of interest. Articles had to at least report data on maternal outcomes of women with GDM.

Results

The search strategies identified 14′419 citations after excluding duplicates. After screening titles and then abstracts, 114 articles were selected for detailed evaluation of their full text, and 16 were included in this review: two observational and 14 intervention studies. Results from observational studies showed that psychosocial well-being (social support and self-efficacy) were positively associated with physical activity and dietary choice. Intervention studies always included diet and physical activity interventions, although none integrated psychosocial well-being in the intervention. These lifestyle interventions mostly led to increased physical activity, improved diet and lower stress perception. Many of these lifestyle interventions also reduced BMI and postpartum diabetes status, improved metabolic outcomes and reduced the risk of preterm deliveries and low birth weight.

Conclusion

This integrative review showed that psychosocial well-being interacted with diet as well as with physical activity in women with GDM. We recommend that future studies consider integrating psychosocial well-being in their intervention, as observational studies demonstrated that social support and self-efficacy helped with adopting a healthy lifestyle following GDM diagnosis.

Electronic supplementary material

The online version of this article (10.1186/s12884-019-2185-y) contains supplementary material, which is available to authorized users.

Attenuation of maternal weight gain impacts infant birthweight: systematic review and meta-analysis

Despite many interventions aiming to reduce excessive gestational weight gain (GWG), it is currently unclear the impact on infant anthropometric outcomes. The aim of this review was to evaluate offspring anthropometric outcomes in studies designed to reduce GWG. A systematic search of seven international databases, one clinical trial registry and three Chinese databases was conducted without date limits. Studies were categorised by intervention type: diet, physical activity (PA), lifestyle (diet + PA), other, gestational diabetes mellitus (GDM) (diet, PA, lifestyle, metformin and other). Meta-analyses were reported as weighted mean difference (WMD) for birthweight and birth length, and risk ratio (RR) for small for gestational age (SGA), large for gestational age (LGA), macrosomia and low birth weight (LBW). Collectively, interventions reduced birthweight, risk of macrosomia and LGA by 71 g (WMD: -70.67, 95% CI -101.90 to -39.43, P&lt;0.001), 16% (RR: 0.84, 95% CI 0.73-0.98, P=0.026) and 19% (RR: 0.81, 95% CI 0.69-0.96, P=0.015), respectively. Diet interventions decreased birthweight and LGA by 99 g (WMD -98.80, 95% CI -178.85 to -18.76, P=0.016) and 65% (RR: 0.35, 95% CI 0.17-0.72, P=0.004). PA interventions reduced the risk of macrosomia by 51% (RR: 0.49, 95% CI 0.26-0.92, P=0.036). In women with GDM, diet and lifestyle interventions reduced birthweight by 211 and 296 g, respectively (WMD: -210.93, 95% CI -374.77 to -46.71, P=0.012 and WMD:-295.93, 95% CI -501.76 to -90.10, P=0.005, respectively). Interventions designed to reduce excessive GWG lead to a small reduction in infant birthweight and risk of macrosomia and LGA, without influencing the risk of adverse outcomes including LBW and SGA.

Dietary Quality and Glycemic Control Among Women with Gestational Diabetes Mellitus

BACKGROUND/OBJECTIVE

Poor dietary quality, measured by the Healthy Eating Index 2010 (HEI-2010), is associated with risk of gestational diabetes mellitus (GDM) and type 2 diabetes. The aim was to investigate the association between dietary quality and glycemic control in women with GDM.

MATERIALS AND METHODS

The study included 1220 women with GDM. Dietary quality was calculated by HEI-2010 score from a Food Frequency Questionnaire administered shortly after GDM diagnosis; higher scores indicate higher dietary quality. Subsequent glycemic control was defined as ≥80% of all capillary glucose measurements meeting recommended clinical targets below 95 mg/dL for fasting, and below 140 mg/dL 1-hour glucose after meals.

RESULTS

As compared with Quartile 1 of HEI-2010 score, Quartiles 2, 3, and 4 showed increased adjusted odds of overall optimal glycemic control (odds ratio [95% confidence interval] 1.90 [1.34-2.70], 1.77 [1.25-2.52], and 1.55 [1.09-2.20], respectively). Increased odds of glycemic control were observed in Quartiles 2, 3, and 4 as compared with Quartile 1 of HEI-2010 score for 1-hour postbreakfast and 1-hour postdinner. Mean capillary glucose was lower in Quartiles 2, 3, and 4 of HEI-2010 score when compared with Quartile 1 for 1-hour postdinner (p = 0.03).

CONCLUSIONS

Clinicians should be aware that even a small improvement in diet quality may be beneficial for the achievement of improved glycemic control in women with GDM.

TRIAL REGISTRATION

Clinical Trials.gov number, NCT01344278.

Improving the effectiveness of lifestyle interventions for gestational diabetes prevention: a meta-analysis and meta-regression

BACKGROUND

Diet and exercise during pregnancy have been used to prevent gestational diabetes mellitus (GDM) with some success.

OBJECTIVE

To examine the effectiveness of lifestyle intervention on GDM prevention and to identify key effectiveness moderators to improve the prevention strategy.

SEARCH STRATEGY

Pubmed, Scopus, Cochrane, and cross-references were searched.

SELECTION CRITERIA

Randomised controlled trials (RCTs) evaluating lifestyle interventions during pregnancy for GDM prevention.

DATA COLLECTION AND ANALYSIS

Two independent reviewers extracted data. A random-effects model was used to analyse the relative risk (RR) and 95% confidence interval (95% CI). Meta-regressions and subgroup analyses were used to investigate important moderators of effectiveness.

MAIN RESULTS

Forty-seven RCTs involving 15 745 participants showed that diet and exercise during pregnancy were preventive of GDM (RR 0.77, 95% CI 0.69-0.87). Four key aspects were identified to improve the preventive effect: targeting the high-risk population; an early initiation of the intervention; the correct intensity and frequency of exercise; and gestational weight gain management. Although 24 RCTs targeted women who were overweight or obese, body mass index (BMI) failed to predict the effectiveness of an intervention. Instead, interventions are most effective in high-incidence populations rather than simply in women who are overweight or obese. Furthermore, exercise of moderate intensity for 50-60 minutes twice a week could lead to an approximately 24% reduction in GDM.

CONCLUSION

The best strategy to prevent GDM is to target the high-risk population predicted by risk evaluation models and to control the gestational weight gain of women through intensified diet and exercise modifications early in their pregnancy.

TWEETABLE ABSTRACT

Four key effectiveness moderators of lifestyle interventions for GDM prevention.

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.

Attenuating Pregnancy Weight Gain-What Works and Why: A Systematic Review and Meta-Analysis

Excessive maternal gestational weight gain (GWG) contributes to generational obesity. Our aim was to explore efficacy and intervention characteristics (trimester, duration, frequency, intensity, and delivery method) of interventions to prevent excessive GWG. CINAHL, Cochrane, EMBASE, LILACS, MEDLINE, PsycINFO, and Scopus were searched up to May 2018 (no date or language restrictions). Keywords and MeSH terms for diet, GWG, intervention, lifestyle, maternal, physical activity, and pregnancy were used to locate randomized-controlled trials (RCTs). The Cochrane Collaboration tool for assessing risk of bias was applied. Eighty-nine RCTs were included. Meta-analysis (60 trials) estimated that women in diet only (WMD: -3.27; 95% CI: -4.96, -1.58, p < 0.01), physical activity (PA) (WMD: -1.02; 95% CI: -1.56, -0.49, p < 0.01), and lifestyle interventions (combining diet and PA) (WMD: -0.84; 95% CI: -1.29, -0.39, p < 0.01) gained significantly less weight than controls. The three eHealth interventions favored neither intervention nor control (WMD: -1.06; 95% CI: -4.13, 2.00, p = 0.50). Meta-regression demonstrated no optimal duration, frequency, intensity, setting, or diet type. Traditional face to face delivery of weight management interventions during pregnancy can be successful. Delivery via eHealth has potential to extend its reach to younger women but needs further evaluation of its success.

Interventions designed to reduce excessive gestational weight gain can reduce the incidence of gestational diabetes mellitus: A systematic review and meta-analysis of randomised controlled trials

AIMS

To (i) evaluate the global impact of interventions designed to prevent excessive gestational weight gain (eGWG) on the incidence of gestational diabetes (GDM), and (ii) examine whether the effects differ by pre-conception body mass index (BMI) or ethnicity.

METHODS

A systematic search of randomised controlled trials (RCTs) with a primary or secondary aim to reduce eGWG was conducted in seven international and three Chinese databases without date limits. Meta-analysis data are reported as relative risk (RR) for GDM incidence for interventions including: diet, physical activity (PA), and lifestyle (diet and PA).

RESULTS

Forty-five studies were included, 37 in the meta-analyses. Diet and PA interventions reduced GDM risk by 44% (RR: 0.56, 95% CI: 0.36-0.87) and 38% (RR: 0.62, 95% CI: 0.50-0.78), respectively. Lifestyle interventions and BMI didn't significantly alter GDM risk. PA interventions from Southern-Europe reduced GDM risk by 37% (RR: 0.63, 95% CI: 0.50-0.80). Whereas, diet and lifestyle interventions conducted in Asia reduced GDM risk by 62% (RR: 0.38, 95% CI: 0.24-0.59) and 32% (RR: 0.68, 95% CI: 0.54-0.86), respectively.

CONCLUSION

Diet and PA interventions designed to reduce GWG are more effective than standard care in reducing the incidence of GDM, although the effect varies by region and BMI. The 'one size fits all' approach is not supported.

Feeding a slowly digestible carbohydrate diet during pregnancy of insulin-resistant rats prevents the excess of adipogenesis in their offspring

An obesogenic environment during pregnancy has been shown to increase the risk of dysregulation on adipogenesis and insulin resistance in the offspring. Being essential for the growing fetus, glucose supply is guaranteed by a number of modifications in the mother's metabolism, and thus, glucose control during pregnancy especially among obese or diabetic women is paramount to prevent adverse consequences in their children. Besides the election of low-glycemic-index carbohydrates, the rate of carbohydrate digestion could be relevant to keep a good glucose control. In the present study, we compared the effects of two high-fat diets with similar glycemic load but different rates of carbohydrate digestion given to pregnant insulin-resistant rats. After birth, all animals were fed a standard diet until age 14 weeks. We analyzed offspring body composition, plasma and adipocyte lipidomics, lipid metabolism in adipose tissue and insulin sensitivity. Those animals whose mothers were fed the rapid-digesting carbohydrate diet exhibited an excessive adipogenesis. Thus, these animals showed a marked lipidemia, increased lipid synthesis in the adipose tissue and reduced glucose transporter amount in the adipose. On the contrary, those animals whose mothers were fed the slow-digesting carbohydrate diet showed a profile in the measured parameters closer to that of the offspring of healthy mothers. These results support the hypothesis that not only glycemic index but the rate of carbohydrate digestion during gestation may be critical to regulate the programming of adipogenesis in the offspring.

A systematic review of interventions for Hispanic women with or at risk of Gestational diabetes mellitus (GDM)

BACKGROUND AND OBJECTIVE

Gestational Diabetes Mellitus (GDM) is a serious health concern for pregnant women, with Hispanic women at particular risk for developing the condition. The aim of this review was to critically examine GDM intervention programs for Hispanic women, in the United States of America (US).

METHODS

English and Spanish electronic databases were searched for relevant studies published between 1995 and 2015. Eligible study designs included randomized controlled trial, pre/post-test and quasi experimental methods.

RESULTS

Findings indicated that there was a dearth of literature reporting on GDM interventions for Hispanic women and just seven papers met inclusion criteria. These seven studies were included in the review and they reported on interventions for: (1) pregnant women at high risk of developing GDM; (2) pregnant women with GDM. Results suggest that a combination of intensive counselling over a prolonged period of time, together with a low calorie, possibly low glycemic index diet, produces best results.

CONCLUSION

The review found that intensive nutritional counselling approaches which promote low calorie/low GI diets appear to be most effective in BGL management in this population. Interventions that are delivered in Spanish and culturally tailored may be more acceptable to participants. More research is needed to develop suitable interventions to improve GDM management among Hispanic women.

Dietary advice interventions in pregnancy for preventing gestational diabetes mellitus

BACKGROUND

Gestational diabetes mellitus (GDM) is a form of diabetes occurring during pregnancy which can result in short- and long-term adverse outcomes for women and babies. With an increasing prevalence worldwide, there is a need to assess strategies, including dietary advice interventions, that might prevent GDM.

OBJECTIVES

To assess the effects of dietary advice interventions for preventing GDM and associated adverse health outcomes for women and their babies.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (3 January 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs assessing the effects of dietary advice interventions compared with no intervention (standard care), or to different dietary advice interventions. Cluster-RCTs were eligible for inclusion but none were identified.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility, extracted data and assessed the risk of bias of the included studies. Data were checked for accuracy. The quality of the evidence was assessed using the GRADE approach.

MAIN RESULTS

We included 11 trials involving 2786 women and their babies, with an overall unclear to moderate risk of bias. Six trials compared dietary advice interventions with standard care; four compared low glycaemic index (GI) with moderate- to high-GI dietary advice; one compared specific (high-fibre focused) with standard dietary advice. Dietary advice interventions versus standard care (six trials) Considering primary outcomes, a trend towards a reduction in GDM was observed for women receiving dietary advice compared with standard care (average risk ratio (RR) 0.60, 95% confidence interval (CI) 0.35 to 1.04; five trials, 1279 women; Tau² = 0.20; I² = 56%; P = 0.07; GRADE: very low-quality evidence); subgroup analysis suggested a greater treatment effect for overweight and obese women receiving dietary advice. While no clear difference was observed for pre-eclampsia (RR 0.61, 95% CI 0.25 to 1.46; two trials, 282 women; GRADE: low-quality evidence) a reduction in pregnancy-induced hypertension was observed for women receiving dietary advice (RR 0.30, 95% CI 0.10 to 0.88; two trials, 282 women; GRADE: low-quality evidence). One trial reported on perinatal mortality, and no deaths were observed (GRADE: very low-quality evidence). None of the trials reported on large-for-gestational age or neonatal mortality and morbidity.For secondary outcomes, no clear differences were seen for caesarean section (average RR 0.98, 95% CI 0.78 to 1.24; four trials, 1194 women; Tau² = 0.02; I² = 36%; GRADE: low-quality evidence) or perineal trauma (RR 0.83, 95% CI 0.23 to 3.08; one trial, 759 women; GRADE: very low-quality evidence). Women who received dietary advice gained less weight during pregnancy (mean difference (MD) -4.70 kg, 95% CI -8.07 to -1.34; five trials, 1336 women; Tau² = 13.64; I² = 96%; GRADE: low-quality evidence); the result should be interpreted with some caution due to considerable heterogeneity. No clear differences were seen for the majority of secondary outcomes reported, including childhood/adulthood adiposity (skin-fold thickness at six months) (MD -0.10 mm, 95% CI -0.71 to 0.51; one trial, 132 children; GRADE: low-quality evidence). Women receiving dietary advice had a lower well-being score between 14 and 28 weeks, more weight loss at three months, and were less likely to have glucose intolerance (one trial).The trials did not report on other secondary outcomes, particularly those related to long-term health and health service use and costs. We were not able to assess the following outcomes using GRADE: postnatal depression; maternal type 2 diabetes; neonatal hypoglycaemia; childhood/adulthood type 2 diabetes; and neurosensory disability. Low-GI dietary advice versus moderate- to high-GI dietary advice (four trials) Considering primary outcomes, no clear differences were shown in the risks of GDM (RR 0.91, 95% CI 0.63 to 1.31; four trials, 912 women; GRADE: low-quality evidence) or large-for-gestational age (average RR 0.60, 95% CI 0.19 to 1.86; three trials, 777 babies; Tau² = 0.61; P = 0.07; I² = 62%; GRADE: very low-quality evidence) between the low-GI and moderate- to high-GI dietary advice groups. The trials did not report on: hypertensive disorders of pregnancy; perinatal mortality; neonatal mortality and morbidity.No clear differences were shown for caesarean birth (RR 1.27, 95% CI 0.79 to 2.04; two trials, 201 women; GRADE: very low-quality evidence) and gestational weight gain (MD -1.23 kg, 95% CI -4.08 to 1.61; four trials, 787 women; Tau² = 7.31; I² = 90%; GRADE: very low-quality evidence), or for other reported secondary outcomes.The trials did not report the majority of secondary outcomes including those related to long-term health and health service use and costs. We were not able to assess the following outcomes using GRADE: perineal trauma; postnatal depression; maternal type 2 diabetes; neonatal hypoglycaemia; childhood/adulthood adiposity; type 2 diabetes; and neurosensory disability. High-fibre dietary advice versus standard dietary advice (one trial) The one trial in this comparison reported on two secondary outcomes. No clear difference between the high-fibre and standard dietary advice groups observed for mean blood glucose (following an oral glucose tolerance test at 35 weeks), and birthweight.

AUTHORS' CONCLUSIONS

Very low-quality evidence from five trials suggests a possible reduction in GDM risk for women receiving dietary advice versus standard care, and low-quality evidence from four trials suggests no clear difference for women receiving low- versus moderate- to high-GI dietary advice. A possible reduction in pregnancy-induced hypertension for women receiving dietary advice was observed and no clear differences were seen for other reported primary outcomes. There were few outcome data for secondary outcomes.For outcomes assessed using GRADE, evidence was considered to be low to very low quality, with downgrading based on study limitations (risk of bias), imprecision, and inconsistency.More high-quality evidence is needed to determine the effects of dietary advice interventions in pregnancy. Future trials should be designed to monitor adherence, women's views and preferences, and powered to evaluate effects on short- and long-term outcomes; there is a need for such trials to collect and report on core outcomes for GDM research. We have identified five ongoing studies and four are awaiting classification. We will consider these in the next review update.

Persistent influence of maternal obesity on offspring health: Mechanisms from animal models and clinical studies

The consequences of excessive maternal weight and adiposity at conception for the offspring are now well recognized. Maternal obesity increases the risk of overweight and obesity even in children born with appropriate-for-gestational age (AGA) birth weights. Studies in animal models have employed both caloric excess and manipulation of macronutrients (especially high-fat) to mimic hypercaloric intake present in obesity. Findings from these studies show transmission of susceptibility to obesity, metabolic dysfunction, alterations in glucose homeostasis, hepatic steatosis, skeletal muscle metabolism and neuroendocrine changes in the offspring. This review summarizes the essential literature in this area in both experimental and clinical domains and focuses on the translatable aspects of these experimental studies. Moreover this review highlights emerging mechanisms broadly explaining maternal obesity-associated developmental programming. The roles of early developmental alterations and placental adaptations are also reviewed. Increasing evidence also points to changes in the epigenome and other emerging mechanisms such as alterations in the microbiome that may contribute to persistent changes in the offspring. Finally, we examine potential interventions that have been employed in clinical cohorts.

Dietary interventions in overweight and obese pregnant women: a systematic review of the content, delivery, and outcomes of randomized controlled trials

CONTEXT

Interventions targeting maternal obesity are a healthcare and public health priority.

OBJECTIVE

The objective of this review was to evaluate the adequacy and effectiveness of the methodological designs implemented in dietary intervention trials for obesity in pregnancy.

DATA SOURCES

A systematic review of the literature, consistent with PRISMA guidelines, was performed as part of the International Weight Management in Pregnancy collaboration.

STUDY SELECTION

Thirteen randomized controlled trials, which aimed to modify diet and physical activity in overweight and obese pregnant women, were identified.

DATA SYNTHESIS

There was significant variability in the content, delivery, and dietary assessment methods of the dietary interventions examined. A number of studies demonstrated improved dietary behavior in response to diet and/or lifestyle interventions. Nine studies reduced gestational weight gain.

CONCLUSION

This review reveals large methodological variability in dietary interventions to control gestational weight gain and improve clinical outcomes in overweight and obese pregnant women. This lack of consensus limits the ability to develop clinical guidelines and apply the evidence in clinical practice.

Effects of low-glycemic-index diets in pregnancy on maternal and newborn outcomes in pregnant women: a meta-analysis of randomized controlled trials

PURPOSE

Maternal diet with a high glycemic index (GI) is associated with fetal overgrowth and higher infant body adiposity. Effects of low-GI diet on maternal and newborn outcomes have been assessed in both healthy pregnancy and gestational diabetes mellitus, but the results remain inconclusive. This meta-analysis aimed to examine the effects of low-GI diets on maternal and newborn outcomes.

METHODS

PubMed, Clinical Trials, and Cochrane Library databases were searched for relevant randomized trials up to January 2016. Random- or fixed-effects models were used to calculate combined treatment effects.

RESULTS

A total of 11 trials involving 1985 women were eligible for analysis. This meta-analysis assessed 7 maternal and 11 newborn outcomes. Of these, gestational weight gain (GWG), fasting blood glucose (FBG), newborn birth weight, ponderal index (PI), proportion of macrosomia, and large for gestational age (LGA) were investigated in more than 8 trials. Compared with control diets, low-GI diets significantly reduced FBG (weight mean differences (WMD) = -0.18 mmol/L, 95 % CI: -0.33, -0.02), 2-h postprandial glucose level (WMD = -0.33 mmol/L, 95 % CI: -0.54, -0.12), and the proportion of LGA (RR = 0.52, 95 % CI: 0.31, 0.89). A lower GWG (WMD = -0.69 kg, 95 % CI: -1.74, 0.36) and birth weight (WMD = -0.10 kg, 95 % CI: -0.23, 0.03) were also observed without significant differences. Heterogeneity was observed in the GWG, FBG, and birth weight analyses. Low-GI diets did not affect other maternal and newborn outcomes. In subgroup and sensitivity analyses, the intervention effects of low GI on GWG and FBG varied.

CONCLUSIONS

Low-GI diets may have beneficial effects on maternal outcomes for those at risk of developing high glucose levels, without causing adverse effects on newborn outcomes. However, results should be interpreted with caution because of the evidence of heterogeneity and limited number of studies.

Effect of a diet intervention during pregnancy on dietary behavior in the randomized controlled Norwegian Fit for Delivery study

A mother's diet during pregnancy has the potential to influence both her own and her child's short- and long-term health. This paper reports the effects of a randomized controlled diet intervention during pregnancy on dietary behavior post-intervention as reported in late pregnancy. The diet intervention was part of a lifestyle intervention targeting both diet and physical activity behaviors among nulliparous women participating in the randomized controlled Norwegian Fit for Delivery study (NFFD). Eligible women were enrolled in early pregnancy from eight healthcare clinics in southern Norway between 2009 and 2013. The diet intervention was based on 10 dietary recommendations that were conveyed during two counseling sessions by phone and in a pamphlet describing the recommendations and their simplified rationale. A diet score was constructed from a 43-item food frequency questionnaire (FFQ) and used to assess intervention effect on dietary behavior (score range 0-10). Between-group dietary differences post-intervention were estimated with analysis of covariance, with adjustment for baseline diet. A total of 508 women completed the FFQ both at baseline and post-intervention. There were no between-group differences in diet score and subscales at baseline. Post-intervention, the intervention group had higher overall diet score (control: 4.61, intervention: 5.04, P=0.013) and favorable dietary behavior in seven of the 10 dietary domains: 'consumption of water relative to total beverage consumption' (P=0.002), 'having vegetables with dinner' (P=0.027), 'choosing fruits and vegetables for between-meal snacks' (P=0.023), 'buying small portion sizes of unhealthy foods' (P=0.010), 'limiting sugar intake' (P=0.005), 'avoiding eating beyond satiety' (P=0.009) and 'reading food labels' (P=0.011). The NFFD diet intervention improved dietary behavior. Potential long-term clinical influence in mother and child will be investigated in further studies.

The association between maternal nutrition and lifestyle during pregnancy and 2-year-old offspring adiposity: analysis from the ROLO study

Aim

To examine the association between maternal nutrition and lifestyle factors and offspring adiposity, using baseline and 2-year postpartum follow-up data from a randomised control trial of low glycaemic index diet.

Subject and methods

Food diaries and lifestyle questionnaires were completed during pregnancy and infant feeding and maternal lifestyle questionnaires 2 years postpartum for 281 mother and infant pairs from the ROLO study. Maternal anthropometry was measured throughout pregnancy and infant and maternal anthropometry was measured 2 years postpartum.

Results

Maternal 2 year postpartum body mass index (BMI) was positively associated with offspring BMI-for-age z-score (B = 0.105, p = 0.015). Trimester 2 saturated fat intake was positively associated with offspring subscapular:triceps skinfold ratio (B = 0.018, p = 0.001). Trimester 1 glycaemic index was also positively associated with offspring sum of subscapular and triceps skinfolds (B = 0.009, p = 0.029).

Conclusions

Maternal BMI 2 years postpartum was positively associated with offspring BMI. Pregnancy saturated fat intake was positively and polyunsaturated fat negatively associated with offspring adiposity. While further research is necessary, pregnancy and the postpartum period may be early opportunities to combat childhood obesity.

Electronic supplementary material

The online version of this article (doi:10.1007/s10389-016-0740-9) contains supplementary material, which is available to authorized users.

Effects of Low Glycemic Index Diets on Gestational Diabetes Mellitus: A Meta-Analysis of Randomized Controlled Clinical Trials

Studies of the effects of low glycemic index (LGI) diets on gestational diabetes mellitus (GDM) have reported conflicting findings.The aim of the study was to evaluate the results of randomized controlled trials (RCTs) that investigated the effects of LGI diets with and without added dietary fiber (DF) on maternal and neonatal outcomes in GDM patients.We searched the MEDLINE, EMBASE, EBSCO, Springer, Ovid, and Cochrane Library databases for studies of the effects of LGI diets in GDM patients. We performed a meta-analysis of the effects of the LGI diets with and without added dietary fiber (DF) on GDM outcomes. Risk ratios (RR) and 95% confidence intervals (CIs) were calculated using random- and fixed-effects models.Five RCTs involving 302 participants were included in our meta-analysis. No statistically significant differences in the risks of cesarean section delivery, large for gestational age, and small for gestational age were observed. The risk of macrosomia in the LGI groups was significantly lower (RR = 0.27; 95% CI: 0.10-0.71; P = 0.008) than that in the control groups. Our subgroup analysis of the effects of DF showed that LGI diets with an increased level of DF, relative to the control diet, reduced the risk of macrosomia beyond that of the LGI diets alone (RR: 0.17 vs 0.47, respectively). The subgroup analysis also showed that LGI diets in which the level of DF was approximately equivalent to that in the control diets significantly reduced the risk of insulin usage (RR = 0.69; 95% CI: 0.52-0.92; P = 0.01).The LGI diets reduced the risk of macrosomia in GDM patients, and LGI diets with added DF reduced the risk of macrosomia further. The LGI diets with levels of DF approximately equivalent to that in the control diets reduced the risk of insulin usage in GDM patients.

A systematic review and metaanalysis of energy intake and weight gain in pregnancy

BACKGROUND

Gestational weight gain within the recommended range produces optimal pregnancy outcomes, yet many women exceed the guidelines. Official recommendations to increase energy intake by ∼ 1000 kJ/day in pregnancy may be excessive.

OBJECTIVE

To determine by metaanalysis of relevant studies whether greater increments in energy intake from early to late pregnancy corresponded to greater or excessive gestational weight gain.

DATA SOURCES

We systematically searched electronic databases for observational and intervention studies published from 1990 to the present. The databases included Ovid Medline, Cochrane Library, Excerpta Medica DataBASE (EMBASE), Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Science Direct. In addition we hand-searched reference lists of all identified articles.

STUDY ELIGIBILITY CRITERIA

Studies were included if they reported gestational weight gain and energy intake in early and late gestation in women of any age with a singleton pregnancy. Search also encompassed journals emerging from both developed and developing countries.

STUDY APPRAISAL AND SYNTHESIS METHODS

Studies were individually assessed for quality based on the Quality Criteria Checklist obtained from the Evidence Analysis Manual: Steps in the academy evidence analysis process. Publication bias was plotted by the use of a funnel plot with standard mean difference against standard error. Identified studies were meta-analyzed and stratified by body mass index, study design, dietary methodology, and country status (developed/developing) by the use of a random-effects model.

RESULTS

Of 2487 articles screened, 18 studies met inclusion criteria. On average, women gained 12.0 (2.8) kg (standardized mean difference = 1.306, P < .0005) yet reported only a small increment in energy intake that did not reach statistical significance (∼475 kJ/day, standard mean difference = 0.266, P = .016). Irrespective of baseline body mass index, study design, dietary methodology, or country status, changes in energy intake were not significantly correlated to the amount of gestational weight gain (r = 0.321, P = .11).

CONCLUSION

Despite rapid physiologic weight gain, women report little or no change in energy intake during pregnancy. Current recommendations to increase energy intake by ∼ 1000 kJ/day may, therefore, encourage excessive weight gain and adverse pregnancy outcomes.

Use of a web-based dietary assessment tool in early pregnancy

BACKGROUND

Maternal diet is critical to fetal development and lifelong health outcomes. In this context, dietary quality indices in pregnancy should be explicitly underpinned by data correlating food intake patterns with nutrient intakes known to be important for gestation.

AIMS

Our aim was to assess the correlation between dietary quality scores derived from a novel online dietary assessment tool (DAT) and nutrient intake data derived from the previously validated Willett Food Frequency Questionnaire (WFFQ).

METHODS

524 women completed the validated semi-quantitive WFFQ and online DAT questionnaire in their first trimester. Spearman correlation and Kruskal-Wallis tests were used to test associations between energy-adjusted and energy-unadjusted nutrient intakes derived from the WFFQ, and diet and nutrition scores obtained from the DAT.

RESULTS

Positive correlations were observed between respondents' diet and nutrition scores derived from the online DAT, and their folate, vitamin B12, iron, calcium, zinc and iodine intakes/MJ of energy consumed derived from the WFFQ (all P < 0.001). Negative correlations were observed between participants' diet and nutrition scores and their total energy intake (P = 0.02), and their percentage energy from fat, saturated fat, and non-milk extrinsic sugars (NMES) (all P ≤ 0.001). Median dietary fibre, beta carotene, folate, vitamin C and vitamin D intakes derived from the WFFQ, generally increased across quartiles of diet and nutrition score (all P < 0.001).

CONCLUSIONS

Scores generated by this web-based DAT correlate with important nutrient intakes in pregnancy, supporting its use in estimating overall dietary quality among obstetric populations.

The effect of maternal and post-weaning low and high glycaemic index diets on glucose tolerance, fat deposition and hepatic function in rat offspring

Clinical studies have reported beneficial effects of a maternal low glycaemic index (GI) diet on pregnancy and neonatal outcomes, but the impact of the diet on the offspring in later life, and the mechanisms underlying these effects, remain unclear. In this study, Albino Wistar rats were fed either a low GI (n=14) or high GI (n=14) diet during pregnancy and lactation and their offspring weaned onto either the low or high GI diet. Low GI dams had better glucose tolerance (AUC[glucose], 1322±55 v. 1523±72 mmol min/l, P<0.05) and a lower proportion of visceral fat (19.0±2.9 v. 21.7±3.8% of total body fat, P<0.05) compared to high GI dams. Female offspring of low GI dams had lower visceral adiposity (0.45±0.03 v. 0.53±0.03% body weight, P<0.05) and higher glucose tolerance (AUC[glucose], 1243±29 v. 1351±39 mmol min/l, P<0.05) at weaning, as well as lower hepatic PI3K-p85 mRNA at 12 weeks of age. No differences in glucose tolerance or hepatic gene expression were observed in male offspring, but the male low GI offspring did have reduced hepatic lipid content at weaning. These findings suggest that consuming a low GI diet during pregnancy and lactation can improve glucose tolerance and reduce visceral adiposity in the female offspring at weaning, and may potentially produce long-term reductions in the hepatic lipogenic capacity of these offspring.

Intake of carbohydrates during pregnancy in obese women is associated with fat mass in the newborn offspring

BACKGROUND

Transmission of obesity across generations is of concern. Offspring of obese women have short- and long-term increased morbidities. A high intake of carbohydrate during pregnancy combined with impaired glucose tolerance is postulated to result in high birth weight, which is linked to subsequent metabolic disease.

OBJECTIVE

The objective was to examine the association between carbohydrate intake in obese pregnant women and their offspring's body composition.

DESIGN

Secondary analyses were performed in an observational setting of 222 pregnant women with a pregestational BMI (in kg/m(2)) ≥30 participating in a randomized controlled trial. Diet was assessed at gestational weeks 11-14 and 36-37 by using a semiquantitative food-frequency questionnaire. Body composition in the offspring was assessed at birth by dual-energy X-ray absorptiometry. Relative fat mass (%) was the primary outcome. Absolute measures (total fat, abdominal fat, and lean body mass) were secondary outcomes.

RESULTS

Mean ± SD weight and absolute and relative fat mass in the offspring at birth were 3769 ± 542 g, 436 ± 214 g, and 11% ± 4%, respectively. Maternal intake of digestible carbohydrates was associated with the offspring's relative fat mass in late (P-trend = 0.006) but not early (P-trend = 0.15) pregnancy. A comparison of mothers in the highest (median: 238 g/d) compared with the lowest (median: 188 g/d) quartile of digestible carbohydrate intake showed a mean adjusted higher value in the offspring's relative fat mass of 2.1% (95% CI: 0.6%, 3.7%), which corresponded in absolute terms to a 103-g (95% CI: 27, 179-g) higher fat mass. Abdominal fat mass was also higher. In a strata of women with well-controlled glucose (2-h glucose values ≤6.6 mmol/L), no association between carbohydrate intake and offspring fat mass was observed, but the associations became significant and increased in strength with higher intolerance (strata with 2-h glucose values between 6.7-7.7 and ≥7.8 mmol/L).

CONCLUSION

In obese women, even those without gestational diabetes but with impaired glucose tolerance, a lower carbohydrate intake at moderate levels in late gestation is associated with a lower fat mass in their offspring at birth. The TOP study was registered at clinicaltrials.gov as NCT01345149.

Dietary micronutrient intake during pregnancy is a function of carbohydrate quality

BACKGROUND

Despite normal gestational weight gain, dietary studies in pregnant women show intakes below the recommendations for energy and micronutrients.

OBJECTIVE

This study compared changes in dietary intake from the second to third trimester with emphasis on energy intake and carbohydrate quality.

DESIGN

These post hoc analyses were based on 566 women participating in the Pregnancy and Glycemic Index Outcomes study, a randomized controlled trial comparing the effect of low-glycemic index (GI) dietary advice with healthy eating advice on selected pregnancy outcomes. With the use of multilevel mixed-regression analysis, changes in total energy intake, starch, sugar, fiber intake, GI, and glycemic load (GL) were correlated with intake of different micronutrients.

RESULTS

Energy intake decreased in the third trimester, and most women did not meet the national recommended amounts for iron, folate, and dietary fiber from food sources alone. After adjustment for age, ethnicity, prepregnancy body mass index, and intervention group, change in energy intake was positively related to change in intake of all micronutrients (P < 0.001). GI, GL, and starch intake were inversely related to micronutrient intake (P < 0.001), whereas higher total sugars predicted higher intake (P < 0.001). Associations with dietary fiber were inconsistent.

CONCLUSIONS

Normal pregnancy can be associated with a decline in energy and micronutrient intake from diet. Low dietary GI and GL were the best predictors of a favorable micronutrient profile. This trial was registered at www.anzctr.org.au as ACTRN12610000174088.

Effects of total fat intake on body weight

BACKGROUND

In order to prevent overweight and obesity in the general population we need to understand the relationship between the proportion of energy from fat and resulting weight and body fatness in the general population.

OBJECTIVES

To assess the effects of proportion of energy intake from fat on measures of weight and body fatness (including obesity, waist circumference and body mass index) in people not aiming to lose weight, using all appropriate randomised controlled trials (RCTs) and cohort studies in adults, children and young people

SEARCH METHODS

We searched CENTRAL to March 2014 and MEDLINE, EMBASE and CINAHL to November 2014. We did not limit the search by language. We also checked the references of relevant reviews.

SELECTION CRITERIA

Trials fulfilled the following criteria: 1) randomised intervention trial, 2) included children (aged ≥ 24 months), young people or adults, 3) randomised to a lower fat versus usual or moderate fat diet, without the intention to reduce weight in any participants, 4) not multifactorial and 5) assessed a measure of weight or body fatness after at least six months. We also included cohort studies in children, young people and adults that assessed the proportion of energy from fat at baseline and assessed the relationship with body weight or fatness after at least one year. We duplicated inclusion decisions and resolved disagreement by discussion or referral to a third party.

DATA COLLECTION AND ANALYSIS

We extracted data on the population, intervention, control and outcome measures in duplicate. We extracted measures of weight and body fatness independently in duplicate at all available time points. We performed random-effects meta-analyses, meta-regression, subgrouping, sensitivity and funnel plot analyses.

MAIN RESULTS

We included 32 RCTs (approximately 54,000 participants) and 30 sets of analyses of 25 cohorts. There is consistent evidence from RCTs in adults of a small weight-reducing effect of eating a smaller proportion of energy from fat; this was seen in almost all included studies and was highly resistant to sensitivity analyses. The effect of eating less fat (compared with usual diet) is a mean weight reduction of 1.5 kg (95% confidence interval (CI) -2.0 to -1.1 kg), but greater weight loss results from greater fat reductions. The size of the effect on weight does not alter over time and is mirrored by reductions in body mass index (BMI) (-0.5 kg/m(2), 95% CI -0.7 to -0.3) and waist circumference (-0.3 cm, 95% CI -0.6 to -0.02). Included cohort studies in children and adults most often do not suggest any relationship between total fat intake and later measures of weight, body fatness or change in body fatness. However, there was a suggestion that lower fat intake was associated with smaller increases in weight in middle-aged but not elderly adults, and in change in BMI in the highest validity child cohort.

AUTHORS' CONCLUSIONS

Trials where participants were randomised to a lower fat intake versus usual or moderate fat intake, but with no intention to reduce weight, showed a consistent, stable but small effect of low fat intake on body fatness: slightly lower weight, BMI and waist circumference compared with controls. Greater fat reduction and lower baseline fat intake were both associated with greater reductions in weight. This effect of reducing total fat was not consistently reflected in cohort studies assessing the relationship between total fat intake and later measures of body fatness or change in body fatness in studies of children, young people or adults.

Diet or exercise, or both, for preventing excessive weight gain in pregnancy

BACKGROUND

This is an update of a Cochrane review first published in 2012, Issue 4. Excessive weight gain during pregnancy is associated with poor maternal and neonatal outcomes including gestational diabetes, hypertension, caesarean section, macrosomia, and stillbirth. Diet or exercise interventions, or both, may reduce excessive gestational weight gain (GWG) and associated poor outcomes; however, evidence from the original review was inconclusive.

OBJECTIVES

To evaluate the effectiveness of diet or exercise, or both, interventions for preventing excessive weight gain during pregnancy and associated pregnancy complications.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (5 November 2014), contacted investigators of the previously identified ongoing studies and scanned reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of diet or exercise, or both, interventions for preventing excessive weight gain in pregnancy.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. We organised RCTs according to the type of interventions and pooled data using the random-effects model in the Review Manager software. We also performed subgroup analyses according to the initial risk of adverse effects related to poor weight control. We performed sensitivity analysis to assess the robustness of the findings.

MAIN RESULTS

We included 65 RCTs, out of which 49 RCTs involving 11,444 women contributed data to quantitative meta-analysis. Twenty studies were at moderate-to-high risk of bias. Study interventions involved mainly diet only, exercise only, and combined diet and exercise interventions, usually compared with standard care. Study methods varied widely; therefore, we estimated the average effect across studies and performed sensitivity analysis, where appropriate, by excluding outliers and studies at high risk of bias.Diet or exercise, or both, interventions reduced the risk of excessive GWG on average by 20% overall (average risk ratio (RR) 0.80, 95% confidence interval (CI) 0.73 to 0.87; participants = 7096; studies = 24; I² = 52%). This estimate was robust to sensitivity analysis, which reduced heterogeneity, therefore we graded this evidence as high-quality. Interventions involving low glycaemic load diets, supervised or unsupervised exercise only, or diet and exercise combined all led to similar reductions in the number of women gaining excessive weight in pregnancy.Women receiving diet or exercise, or both interventions were more likely to experience low GWG than those in control groups (average RR 1.14, 95% CI 1.02 to 1.27; participants = 4422; studies = 11; I² = 3%; moderate-quality evidence). We found no difference between intervention and control groups with regard to pre-eclampsia (RR 0.95, 95% CI 0.77 to 1.16; participants = 5330; studies = 15; I² = 0%; high-quality evidence); however, maternal hypertension (not a pre-specified outcome) was reduced in the intervention group compared with the control group overall (average RR 0.70, 95% CI 0.51 to 0.96; participants = 5162; studies = 11; I² = 43%; low-quality evidence).There was no clear difference between groups with regard to caesarean delivery overall (RR 0.95, 95% CI 0.88 to 1.03; participants = 7534; studies = 28; I² = 9%; high-quality evidence); although the effect estimate suggested a small difference (5%) in favour of the interventions. In addition, for combined diet and exercise counselling interventions there was a 13% (-1% to 25%) reduction in this outcome (borderline statistical significance).We found no difference between groups with regard to preterm birth overall (average RR 0.91, 95% CI 0.68 to 1.22; participants = 5923; studies = 16; I² = 16%; moderate-quality evidence); however limited evidence suggested that these effect estimates may differ according to the types of interventions, with a trend towards an increased risk for exercise-only interventions.We found no clear difference between intervention and control groups with regard to infant macrosomia (average RR 0.93, 95% CI 0.86 to 1.02; participants = 8598; studies = 27; I² = 0%; high-quality evidence), although the effect estimate suggested a small difference (7% reduction) in favour of the intervention group. The largest effect size occurred in the supervised exercise-only intervention group (RR 0.81, 95% CI 0.64 to 1.02; participants = 2445; studies = 7; I² = 0%), which approached statistical significance (P = 0.07). Furthermore, in subgroup analysis by risk, high-risk women (overweight or obese women, or women with or at risk of gestational diabetes) receiving combined diet and exercise counselling interventions experienced a 15% reduced risk of infant macrosomia (average RR 0.85, 95% CI 0.73 to 1.00; participants = 3252; studies = nine; I² = 0; P = 0.05; moderate-quality evidence)There were no differences in the risk of poor neonatal outcomes including shoulder dystocia, neonatal hypoglycaemia, hyperbilirubinaemia, or birth trauma (all moderate-quality evidence) between intervention and control groups; however, infants of high-risk women had a reduced risk of respiratory distress syndrome if their mothers were in the intervention group (RR 0.47, 95% CI 0.26 to 0.85; participants = 2256; studies = two; I² = 0%; moderate-quality evidence).

AUTHORS' CONCLUSIONS

High-quality evidence indicates that diet or exercise, or both, during pregnancy can reduce the risk of excessive GWG. Other benefits may include a lower risk of caesarean delivery, macrosomia, and neonatal respiratory morbidity, particularly for high-risk women receiving combined diet and exercise interventions. Maternal hypertension may also be reduced. Exercise appears to be an important part of controlling weight gain in pregnancy and more research is needed to establish safe guidelines. Most included studies were carried out in developed countries and it is not clear whether these results are widely applicable to lower income settings.

Antenatal dietary education and supplementation to increase energy and protein intake

BACKGROUND

Gestational weight gain is positively associated with fetal growth, and observational studies of food supplementation in pregnancy have reported increases in gestational weight gain and fetal growth.

OBJECTIVES

To assess the effects of education during pregnancy to increase energy and protein intake, or of actual energy and protein supplementation, on energy and protein intake, and the effect on maternal and infant health outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 January 2015), reference lists of retrieved studies and contacted researchers in the field.

SELECTION CRITERIA

Randomised controlled trials of dietary education to increase energy and protein intake, or of actual energy and protein supplementation, during pregnancy.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and assessed risk of bias. Two review authors independently extracted data and checked for accuracy. Extracted data were supplemented by additional information from the trialists we contacted.

MAIN RESULTS

We examined 149 reports corresponding to 65 trials. Of these trials, 17 were included, 46 were excluded, and two are ongoing. Overall, 17 trials involving 9030 women were included. For this update, we assessed methodological quality of the included trials using the standard Cochrane criteria (risk of bias) and the GRADE approach. The overall risk of bias was unclear. Nutritional education (five trials, 1090 women) Women given nutritional education had a lower relative risk of having a preterm birth (two trials, 449 women) (risk ratio (RR) 0.46, 95% CI 0.21 to 0.98, low-quality evidence), and low birthweight (one trial, 300 women) (RR 0.04, 95% CI 0.01 to 0.14). Head circumference at birth was increased in one trial (389 women) (mean difference (MD) 0.99 cm, 95% CI 0.43 to 1.55), while birthweight was significantly increased among undernourished women in two trials (320 women) (MD 489.76 g, 95% CI 427.93 to 551.59, low-quality evidence), but did not significantly increase for adequately nourished women (MD 15.00, 95% CI -76.30 to 106.30, one trial, 406 women). Protein intake increased significantly (three trials, 632 women) (protein intake: MD +6.99 g/day, 95% CI 3.02 to 10.97). No significant differences were observed on any other outcomes such as neonatal death (RR 1.28, 95% CI 0.35 to 4.72, one trial, 448 women, low-quality evidence), stillbirth (RR 0.37, 95% CI 0.07 to 1.90, one trial, 431 women, low-quality evidence), small-for-gestational age (RR 0.97, 95% CI 0.45 to 2.11, one trial, 404 women, low-quality evidence) and total gestational weight gain (MD -0.41, 95% CI -4.41 to 3.59, two trials, 233 women). There were no data on perinatal death. Balanced energy and protein supplementation (12 trials, 6705 women)Risk of stillbirth was significantly reduced for women given balanced energy and protein supplementation (RR 0.60, 95% CI 0.39 to 0.94, five trials, 3408 women, moderate-quality evidence), and the mean birthweight was significantly increased (random-effects MD +40.96 g, 95% CI 4.66 to 77.26, Tau² = 1744, I² = 44%, 11 trials, 5385 women, moderate-quality evidence). There was also a significant reduction in the risk of small-for-gestational age (RR 0.79, 95% CI 0.69 to 0.90, I² = 16%, seven trials, 4408 women, moderate-quality evidence). No significant effect was detected for preterm birth (RR 0.96, 95% CI 0.80 to 1.16, five trials, 3384 women, moderate-quality evidence) or neonatal death (RR 0.68, 95% CI 0.43 to 1.07, five trials, 3381 women, low-quality evidence). Weekly gestational weight gain was not significantly increased (MD 18.63, 95% CI -1.81 to 39.07, nine trials, 2391 women, very low quality evidence). There were no data reported on perinatal death and low birthweight. High-protein supplementation (one trial, 1051 women)High-protein supplementation (one trial, 505 women), was associated with a significantly increased risk of small-for-gestational age babies (RR 1.58, 95% CI 1.03 to 2.41, moderate-quality evidence). There was no significant effect for stillbirth (RR 0.81, 95% CI 0.31 to 2.15, one trial, 529 women), neonatal death (RR 2.78, 95% CI 0.75 to 10.36, one trial, 529 women), preterm birth (RR 1.14, 95% CI 0.83 to 1.56, one trial, 505 women), birthweight (MD -73.00, 95% CI -171.26 to 25.26, one trial, 504 women) and weekly gestational weight gain (MD 4.50, 95% CI -33.55 to 42.55, one trial, 486 women, low-quality evidence). No data were reported on perinatal death. Isocaloric protein supplementation (two trials, 184 women)Isocaloric protein supplementation (two trials, 184 women) had no significant effect on birthweight (MD 108.25, 95% CI -220.89 to 437.40) and weekly gestational weight gain (MD 110.45, 95% CI -82.87 to 303.76, very low-quality evidence). No data reported on perinatal mortality, stillbirth, neonatal death, small-for-gestational age, and preterm birth.

AUTHORS' CONCLUSIONS

This review provides encouraging evidence that antenatal nutritional education with the aim of increasing energy and protein intake in the general obstetric population appears to be effective in reducing the risk of preterm birth, low birthweight, increasing head circumference at birth, increasing birthweight among undernourished women, and increasing protein intake. There was no evidence of benefit or adverse effect for any other outcome reported.Balanced energy and protein supplementation seems to improve fetal growth, and may reduce the risk of stillbirth and infants born small-for-gestational age. High-protein supplementation does not seem to be beneficial and may be harmful to the fetus. Balanced-protein supplementation alone had no significant effects on perinatal outcomes.The results of this review should be interpreted with caution. The risk of bias was either unclear or high for at least one category examined in several of the included trials, and the quality of the evidence was low for several important outcomes. Also, as the anthropometric characteristics of the general obstetric population is changing, those developing interventions aimed at altering energy and protein intake should ensure that only those women likely to benefit are included. Large, well-designed randomised trials are needed to assess the effects of increasing energy and protein intake during pregnancy in women whose intake is below recommended levels.

Maternal obesity and metabolic risk to the offspring: why lifestyle interventions may have not achieved the desired outcomes

Obesity during pregnancy is associated with an increased risk of short- and long-term metabolic dysfunction in the mother and her offspring. Both higher maternal pregravid body mass index (kg m(-2)) and excessive gestational weight gain (GWG) have been associated with adverse pregnancy outcomes such as gestational diabetes, preeclampsia and fetal adiposity. Multiple lifestyle intervention trials consisting of weight management using various diets, increased physical activity and behavioral modification techniques have been employed to avoid excessive GWG and improve perinatal outcomes. These randomized controlled trials (RCTs) have achieved modest success in decreasing excessive GWG, although the decrease in GWG was often not within the current Institute of Medicine guidelines. RCTs have generally not had any success with decreasing the risk of maternal gestational diabetes (GDM), preeclampsia or excessive fetal growth often referred to as macrosomia. Although the lack of success for these trials has been attributed to lack of statistical power and poor compliance with study protocols, our own research suggests that maternal pregravid and early pregnancy metabolic condition programs early placenta function and gene expression. These alterations in maternal/placental function occur in the first trimester of pregnancy prior to when most intervention trials are initiated. For example, maternal accrural of adipose tissue relies on prior activation of genes controlling lipogenesis and low-grade inflammation in early pregnancy. These metabolic alterations occur prior to any changes in maternal phenotype. Therefore, trials of lifestyle interventions before pregnancy are needed to demonstrate the safety and efficacy for both the mother and her offspring.

The effects of antenatal dietary and lifestyle advice for women who are overweight or obese on maternal diet and physical activity: the LIMIT randomised trial

BACKGROUND

Overweight and obesity is a significant health concern during pregnancy. Our aim was to investigate the effect of providing antenatal dietary and lifestyle advice to women who are overweight or obese on components of maternal diet and physical activity.

METHODS

We conducted a randomised controlled trial, in which pregnant women with a body mass index≥25 kg/m2, and singleton gestation between 10(+0) to 20(+0) weeks were recruited and randomised to Lifestyle Advice (involving a comprehensive dietary and lifestyle intervention over their pregnancy) or Standard Care. Within the intervention group, we conducted a nested randomised trial in which a subgroup of women were further randomised to receive access to supervised group walking sessions in addition to the standard information presented during the intervention contacts (the Walking group) or standard information only. The outcome measures were maternal dietary intake, (including food groups, macronutrient and micronutrient intake, diet quality (using the Healthy Eating Index; HEI), dietary glycaemic load, and glycaemic index) and maternal physical activity. Women completed the Harvard Semi-Structured Food Frequency Questionnaire, and the Short Questionnaire to Assess Health-enhancing Physical Activity (SQUASH), at trial entry, 28 and 36 weeks' gestational age, and 4 months postpartum. Analyses were performed on an intention-to-treat basis, using linear mixed effects models with adjustment for the stratification variables.

RESULTS

Women randomised to Lifestyle Advice demonstrated a statistically significant increase in the number of servings of fruit and vegetables consumed per day, as well as increased consumption of fibre, and reduced percentage energy intake from saturated fats (P<0.05 for all). Maternal HEI was significantly improved at both 28 (73.35±6.62 versus 71.86±7.01; adjusted difference in means 1.58; 95% CI 0.89 to 2.27; P<0.0001) and 36 (72.95±6.82 versus 71.17±7.69; adjusted difference in means 1.77; 95% CI 1.01 to 2.53; P<0.0001) weeks. There were no differences in dietary glycaemic index or glycaemic load. Women randomised to Lifestyle Advice also demonstrated greater total physical activity (adjusted difference in means 359.76 metabolic equivalent task units (MET) minutes/week; 95% CI 74.87 to 644.65; P=0.01) compared with women receiving Standard Care. The supervised walking group was poorly utilised.

CONCLUSIONS

For women who are overweight or obese, antenatal lifestyle advice improves maternal diet and physical activity during pregnancy. Please see related articles: http://www.biomedcentral.com/1741-7015/12/163 and http://www.biomedcentral.com/1741-7015/12/201.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry ( ACTRN12607000161426).