Physical activity and gestational diabetes mellitus among Hispanic women

Physical activity during pregnancy and the risk of gestational diabetes mellitus: a systematic review and dose-response meta-analysis

BACKGROUND

Previous research has indicated the inverse association between physical activity (PA) and gestational diabetes mellitus (GDM). However, the dose-response relationship currently remains undetermined. This study aims to explore the dose-response relationship between PA during the first and second trimesters of pregnancy and GDM risk.

METHODS

Studies on the relationship between PA during pregnancy and GDM risk published before April 25, 2023, were searched for in six databases. According to the inclusion and exclusion criteria, all literature was screened for eligibility. The Newcastle-Ottawa Scale (NOS) was used to assess risk of bias. Publication bias was examined using funnel plots, Begg's and Egger's tests, as well as trim-and-fill analysis. We harmonized exposure estimates of PA during pregnancy to the common unit of the metabolic equivalent of task (MET)-h/week. Restricted cubic splines were used to model the dose-response relationship. The criteria from the World Cancer Research Fund were used to assess the certainty of evidence across outcomes. All analyses were performed using Stata 15.1.

RESULTS

The results indicated that in contrast with the lowest level of PA, promoting the highest PA level lowers the risk of GDM by 36% (RR = 0.64, 95%CI: 0.53 ~ 0.78). We found a curvilinear dose-response association between PA during the first trimester and incident GDM (Pnonlinearity = 0.012). Compared to inactive pregnant women, for those who achieved the guidelines-suggested minimum level (10 MET-h/week) of PA during the first trimester, the GDM risk was decreased by 13% (RR = 0.87, 95%CI: 0.79 ~ 0.96). A linear relationship was found between PA during the second trimester and the GDM risk (Pnonlinearity = 0.276). The results with a restricted cubic spline model suggested that pregnant women who accumulate 10 MET-h/week have a 1% reduced risk of GDM compared to completely inactive individuals. Twice (20 MET-h/week) or a higher amount of PA (50 MET-h/week) contributed to further reductions in GDM risk.

CONCLUSION

There is a dose-response relationship between higher levels of PA in both the first and second trimesters and reduced risk of GDM; the relationship is stronger in the first trimester. Increasing PA during pregnancy can prevent the development of GDM.

PROSPERO REGISTRATION NUMBER

CRD42023420564.

Risk Factors of Gestational Diabetes Mellitus Among Women Attending an Antenatal Care Clinic in Prince Sultan Military Medical City (PSMMC), Riyadh, Kingdom of Saudi Arabia: A Case-Control Study

BACKGROUND

Gestational diabetes mellitus (GDM) is a serious health issue for both mother and child. As GDM is common worldwide, healthcare providers pay attention while screening and managing pregnant women to ensure good outcomes for both mother and child.

OBJECTIVE

This study aims to identify the risk factors associated with developing GDM in pregnant women attending antenatal care clinics in Prince Sultan Military Medical City (PSMMC) in Riyadh, Saudi Arabia.

METHODS

This is a case-control study that utilized patients' medical records for data collection. The study included 317 pregnant Saudi women who attended antenatal care clinics and antenatal diabetic clinics in PSMMC from May 2022 to May 2023. Cases were defined as women who met the inclusion and exclusion criteria and had a positive oral glucose tolerance test (OGTT) result, while controls were defined as women in the same age group and gravidity who had negative OGTT. Analysis was conducted using SPSS Statistics version 29.0 (IBM Corp. Released 2021. IBM SPSS Statistics for Windows, Version 29.0. Armonk, NY: IBM Corp.) Results: The total number of cases was 132 out of 313 total samples, representing 42.2% of the total sample. Three factors were associated with an increased risk of developing GDM, including a family history of diabetes (p-value <0.001), a history of GDM (p-value <0.001), and macrosomia (p-value = 0.020). The study also found higher BMI and advanced maternal age were risk factors for GDM (p-value = 0.004, 0.007), respectively. However, the study did not find a significant association between GDM and other factors, such as chronic disease prevalence, history of miscarriage, or history of fetal death.

CONCLUSION

The study identified several risk factors associated with an increased risk of GDM including family history of diabetes, history of GDM, macrosomia, overweight/obesity, and advanced maternal age. It is recommended that antenatal care providers screen for GDM risk factors and closely monitor overweight, obese, or older women. Education and counseling on healthy lifestyle habits, such as maintaining a healthy weight and engaging in physical activity, may also be beneficial for preventing GDM. Further research is needed to confirm and identify additional risk factors for GDM.

A Clinical Update on Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) traditionally refers to abnormal glucose tolerance with onset or first recognition during pregnancy. GDM has long been associated with obstetric and neonatal complications primarily relating to higher infant birthweight and is increasingly recognized as a risk factor for future maternal and offspring cardiometabolic disease. The prevalence of GDM continues to rise internationally due to epidemiological factors including the increase in background rates of obesity in women of reproductive age and rising maternal age and the implementation of the revised International Association of the Diabetes and Pregnancy Study Groups' criteria and diagnostic procedures for GDM. The current lack of international consensus for the diagnosis of GDM reflects its complex historical evolution and pragmatic antenatal resource considerations given GDM is now 1 of the most common complications of pregnancy. Regardless, the contemporary clinical approach to GDM should be informed not only by its short-term complications but also by its longer term prognosis. Recent data demonstrate the effect of early in utero exposure to maternal hyperglycemia, with evidence for fetal overgrowth present prior to the traditional diagnosis of GDM from 24 weeks' gestation, as well as the durable adverse impact of maternal hyperglycemia on child and adolescent metabolism. The major contribution of GDM to the global epidemic of intergenerational cardiometabolic disease highlights the importance of identifying GDM as an early risk factor for type 2 diabetes and cardiovascular disease, broadening the prevailing clinical approach to address longer term maternal and offspring complications following a diagnosis of GDM.

Level of Physical Activity in Pregnant Populations from Different Geographic Regions: A Systematic Review

The aim of this study was to examine the level of physical activity during pregnancy in different populations worldwide. An intensive search was carried out from February until May 2021. The inclusion criteria were original studies of healthy pregnant women, and the main study variable was the assessment of physical activity. A total of 110 out of 1451 studies were assessed for inclusion, using the Newcastle–Ottawa Scale for quality, and for the risk of bias. The 44 analyzed articles were divided into 5 tables according to the characteristics of the intervention and the validated instrument used to measure physical activity (PA). A total of 59.09% of the studies indicated that participants had a low level of physical activity during pregnancy. In addition, the median quality score of the studies was 7.12, and 77.27% of the studies were cataloged as having a high-quality score. Although international guidelines recommend that women without a contraindication engage in prenatal physical activity, the results of the present study show that the level of PA is too low for women to achieve scientifically proven maternal-fetal benefits. Failure to achieve the recommended levels of weekly physical activity could pose significant risks to maternal well-being.

The interaction between metabolic syndrome and physical activity, and risk for gestational diabetes mellitus

AIMS

Metabolic syndrome (MetS) is a cluster of risk factors which increases risk of cardiometabolic diseases in the adult population and increases risk for pregnancy complications such as gestational diabetes mellitus (GDM). Epidemiological data indicate that moderate-to-high levels of physical activity reduces the risk for GDM. The study aims to determine whether the association between MetS and GDM is affected by physical activity.

METHODS

We performed a prospective cohort study among 1373 pregnant nulliparous women in Adelaide, South Australia. At 9-16 weeks' gestation, demographic, lifestyle and self-reported frequencies of physical activity were obtained, and a non-fasting blood sample was taken for assessment of MetS, defined using the International Diabetes Federation criteria. GDM was diagnosed at 24-28 weeks' gestation using the World Health Organization classification.

RESULTS

1158 pregnant women were included: 107 (9%) women had MetS in early pregnancy, and 184 (16%) developed GDM. Having MetS increased the risk of developing GDM (37.4% vs. 13.7%, adjusted RR 2.5; 95% CI 1.7, 3.6). The interaction effect (RR; (95% CI) between MetS and physical activity was not significant (vigorous physical activity: 2.60; 0.46, 14.71) for ≥ 4 times per week; less vigorous activity; 0.77; 0.15, 4.02 for ≥ 4 times per week; stair climbing ≥ once day (1.16; 0.54, 2.51), all compared to no physical activity).

CONCLUSIONS

Physical activity was not an effect modifier in the association between GDM and MetS. Information collected about the nature and extent of physical activity needs to be more detailed and granular to determine whether physical activity really has an effect.

Do the body mass index and the diagnosis of gestational diabetes mellitus influence the level of physical activity during pregnancy and postpartum?

Obesity and lack of physical exercise are associated with the increase of diabetes mellitus in women of reproductive age and during the gestational period. The objective of the present study was to evaluate physical activity levels during the pregnancy and postpartum periods and the influence of body mass index (BMI) in women with gestational diabetes mellitus (GDM) or low risk pregnancy. The Pregnancy Physical Activity Questionnaire (PPAQ), translated and validated for Portuguese, was used for the evaluation of physical activity (PA) level. The sample was stratified according to preconception BMI and the presence or absence of diagnosis of GDM, resulting in four groups with 66 participants each: low risk pregnancy (LRP) with normal weight (BMI ≥ 18.5 and ≤ 24 kg/m2), LRP and overweight/obese (BMI ≥ 25 kg/m2), GDM with normal weight and GDM with overweight/obese. The level of PA of each participant was measured as Metabolic Equivalent of Task (MET) during the preconceptional period (T0), in the third trimester of gestation (T1), and three months after delivery (T2). The comparison of the MET values showed that the values found in the evaluation three months after delivery (T2) were higher than 1.00 (1.10 MET for the LRP-normal weight, 1.06 MET for LRP-overweight/obese, 1.02 MET for the GDM- normal weight, 1.07 MET for the GDM-overweight/obese). On the pre-gestational (T0) and third trimester (T1) analyzes, the values were less than 1.00 MET. The analysis between groups in relation to BMI and diagnosis of GDM showed no difference.

Assessment of physical activity status among pregnant women in southwestern China

Objective

To assess the patterns and intensities of physical activity among pregnant women in southwestern China, which help us create a fitness regimen based on the 2002 American College of Obstetricians and Gynecologists (ACOG) guidelines for exercise during pregnancy.

Methods

A cross-sectional study was performed to recruit pregnant women at a prenatal checking visit clinic with the self-administered Chinese version of Pregnancy Physical Activity Questionnaire (PPAQ).

Results

A total of 1179 Chinese pregnant women were enrolled, of whom 92.60% were classified as not meeting the ACOG guidelines. By intensity, 47.36% of the score was attributed to light-intensity activities (1.5 to <3.0 metabolic equivalent [MET]) in the first trimester; the other 2 trimesters were similar. By patterns, about 45.15% of the score was attributed to inactivity. More than 82.35% of enrolled pregnant women regarded slowly walking as the most common type of exercise during pregnancy.

Conclusions

This study represents a group of Chinese women who maintained an inactive lifestyle, including low-intensity activities and unitary type of exercises during their pregnancy. Health-care providers are advised to provide appropriate physical activity guidelines to pregnant women. Development of MET-hours/week recommendations is warranted to promote greater physical activity during pregnancy.

Association between maternal education level and gestational diabetes mellitus: a meta-analysis

Aims: The association between maternal education and gestational diabetes mellitus (GDM) has been discussed in considerable studies, yet the inconsistent findings still exist. The aim of this study is to investigate whether maternal education level is associated with GDM risk.Material and methods: PubMed, ScienceDirect, and Cochrane Library databases were searched up to October 2018. Observational studies on the association between maternal education level and GDM risk were included. The pooled odds ratios (ORs) and 95% confidence intervals (CIs) for highest versus lowest level of maternal education were estimated using a random-effects model.Results: As compared to lowest education level, the pooled OR for women with highest education level was 0.75 (95% CI: 0.53-1.05). After adjusting for body mass index (BMI) and family history of diabetes, the estimated effect of maternal education on GDM were 0.68 (95% CI: 0.57-0.80) and 0.75 (95% CI: 0.60-0.92), respectively.Conclusions: Our results indicate that there is no significant association between maternal education level and risk of GDM.

I-ACT: Integrated study on effect of Activity on ComplicaTions in pregnancy: study protocol of a multiethnic prospective cohort study

INTRODUCTION

Physical activity (PA) during first 20 weeks of pregnancy may lower risks of gestational diabetes mellitus (GDM) and gestational hypertension (GH), though evidence of association remains inconclusive. Current studies rely heavily on subjective assessment of PA levels. Wearable activity trackers provide a convenient and objective surrogate index for PA validated by evidence-based steps/day categorisation along a physical inactivity/activity continuum. I-ACT primarily aims to examine objectively measured PA levels and patterns in first and second trimesters of pregnancy and the association with GDM and/or GH in Singapore, a multiethnic Asian population. Secondary aims include investigating the bio-socio-demographic factors associated with sedentary behaviour, and association of early pregnancy PA level with maternal weight at 6 weeks postdelivery. Results may facilitate identification of high-risk mothers-to-be and formulation of interventional strategies.

METHODS AND ANALYSIS

Prospective cohort study that will recruit 408 women at first antenatal visit at <12 weeks' gestation. Baseline bio-socio-demographic factors and PA levels assessed by participant characteristics form and the International Physical Activity Questionnaire (IPAQ), respectively. An activity tracker (Fitbit) will be provided to be worn daily from date of recruitment to end of 20 weeks' gestation. Tracker-recorded data will be synchronised with an application on participant's smartphone. Compliance will be reinforced with fortnightly reminders. After 20 weeks, a second IPAQ and a feedback form will be administered. GDM screened at 24-28 weeks' gestation. GH diagnosed after 20-weeks gestation. Maternal weight assessed at 6 weeks postdelivery. Appropriate statistical tests will be used to compare continuous and categorical PA measurements between first and second trimesters. Logistic regression will be used to analyse associations.

ETHICS AND DISSEMINATION

Ethical approval obtained from the Centralised Institutional Review Board of SingHealth (reference 2017/2836). Dissemination of results will be via peer-reviewed research publications both online and in print, conference presentations, posters and medical forums.

Prenatal exercise for the prevention of gestational diabetes mellitus and hypertensive disorders of pregnancy: a systematic review and meta-analysis

Objective

Gestational diabetes mellitus (GDM), gestational hypertension (GH) and pre-eclampsia (PE) are associated with short and long-term health issues for mother and child; prevention of these complications is critically important. This study aimed to perform a systematic review and meta-analysis of the relationships between prenatal exercise and GDM, GH and PE.

Design

Systematic review with random effects meta-analysis and meta-regression.

Data sources

Online databases were searched up to 6 January 2017.

Study eligibility criteria

Studies of all designs were included (except case studies) if published in English, Spanish or French, and contained information on the Population (pregnant women without contraindication to exercise), Intervention (subjective or objective measures of frequency, intensity, duration, volume or type of exercise, alone [“exercise-only”] or in combination with other intervention components [e.g., dietary; “exercise + co-intervention”]), Comparator (no exercise or different frequency, intensity, duration, volume and type of exercise) and Outcomes (GDM, GH, PE).

Results

A total of 106 studies (n=273 182) were included. ‘Moderate’ to ‘high’-quality evidence from randomised controlled trials revealed that exercise-only interventions, but not exercise+cointerventions, reduced odds of GDM (n=6934; OR 0.62, 95% CI 0.52 to 0.75), GH (n=5316; OR 0.61, 95% CI 0.43 to 0.85) and PE (n=3322; OR 0.59, 95% CI 0.37 to 0.9) compared with no exercise. To achieve at least a 25% reduction in the odds of developing GDM, PE and GH, pregnant women need to accumulate at least 600 MET-min/week of moderate-intensity exercise (eg, 140 min of brisk walking, water aerobics, stationary cycling or resistance training).

Summary/conclusions

In conclusion, exercise-only interventions were effective at lowering the odds of developing GDM, GH and PE.

Physical activity during pregnancy is associated with a lower prevalence of gestational diabetes mellitus in Vietnam

AIMS

To assess the association between physical activity (PA) during pregnancy and the prevalence of gestational diabetes mellitus (GDM) accounting for sitting time.

METHODS

The study used data from a cohort study of 2030 pregnant women in Vietnam. Women were recruited from six hospitals in Ha Noi, Hai Phong, and Ho Chi Minh City. Baseline measurements including PA and GDM were taken at 24-28 weeks of gestation. PA was assessed during the past 3 months before the interview using the interviewer-administered Pregnancy Physical Activity Questionnaire. GDM was diagnosed at 24-28 weeks of gestation using the 2013 World Health Organization criteria.

RESULTS

1987 out of 2030 pregnant women were included in the final analysis, of which 432 had GDM (21.7%). Women undertaking the highest level (upper tertile) of PA during pregnancy appeared to have a lower risk of GDM [odds ratio (OR) 0.70, 95% confidence interval (CI) 0.53-0.94, P_trend 0.017] when compared to those at the lowest tertile of PA. Similarly, women with increased levels of moderate-intensive activity and household/caregiving activity during pregnancy were associated with reduced risks of GDM (OR 0.66, 95% CI 0.50-0.86, P_trend 0.002 and OR 0.72, 95% CI 0.55-0.95, P_trend 0.020, respectively). These apparent inverse associations were not attenuated by their sitting time. There were no significant associations between sitting time, light-intensity activity, vigorous-intensity activity, occupation, sports/exercise, commuting, or meeting exercise guidelines and GDM risk.

CONCLUSIONS

High levels of PA, particularly moderate-intensity and household/caregiving activities during pregnancy were associated with a lower prevalence of GDM independent of sitting time.

Effect of Physical Activity during Pregnancy on Gestational Diabetes Mellitus

AIMS

The present study evaluates association between physical activity and Gestational Diabetes Mellitus (GDM), for it can be an effective intervention for its management. Though physical activity helps maintain glucose homeostasis, evidences of GDM risk are less extensive. Therefore, this study also identifies its correlation with maternal blood glucose levels.

MATERIALS AND METHODS

A prospective case-control study was carried out among pregnant women attending regular antenatal clinic at two private hospitals. The study comprised of 100 cases and 273 matched controls. Data was collected by personal interviews using a standard questionnaire. Physical activity was assessed using long form of International Physical Activity Questionnaire (IPAQ) reported as Metabolic Equivalent-Minutes per week (MET-Minutes/Week). Statistical Package for Social Sciences (SPSS) was used for analysis.

RESULTS

Results shows high exposure rates for low-to-moderate physical activity among cases, across all domains and sub-activities. The odds of GDM engaged in domestic and gardening activities for <2999 MET-minutes per week are 10 times higher than involved for ≥3000 MET-minutes per week (P < 0.001). The study also shows poor or no correlation between physical activity during pregnancy and maternal blood glucose levels.

CONCLUSION

Despite existence of poor or no relationship with maternal blood glucose levels, prolonged sedentary behavior and decreased physical activities, especially domestic, are potential risk factors for GDM, a major finding of the study.

Risk Factors for Gestational Diabetes Mellitus: A Case-Control Study

Background: The underlying causes of gestational diabetes mellitus (GDM) are important because they are effective for the diagnosis and prevention of this condition. The aim of this study was to identify the risk factors for GDM and the possible etiological agents. Materials and Methods: This case-control study was conducted with 100 women with GDM and 100 healthy pregnant women at a tertiary care hospital, affiliated to Babol University. GDM was identified by impaired oral glucose tolerance test based on the Carpenter and Coustan criteria. Healthy women were randomly selected from the prenatal health care clinic of the same center and were matched to gestational age of 24 to 28 weeks. Descriptive and inferential statistics were used for data analysis via the SPSS software. Results: After adjusting variables, multivariate analysis identified 4 significant risk factors of GDM, including prepregnancy low physical activity (odds ratio [OR] = 2.85, 95% confidence interval [CI]= 0.97-8.34), advanced maternal age (OR = 1.24, 95% CI = 1.13-1.35), body mass index ⩾ 30 kg/m² (OR = 1.10, 95% CI = 1.02-1.20), and family history of diabetes mellitus (OR = 5.62, 95% CI = 2.26-13.96). Conclusion: We observed significant associations between low prepregnancy physical activity and obesity with GDM risk. Thus the finding of this study can help devise strategies for the prevention of GDM.

Leisure-Time Physical Activity in Pregnancy and Maternal-Child Health: A Systematic Review and Meta-Analysis of Randomized Controlled Trials and Cohort Studies

BACKGROUND

Evidence suggests that leisure-time physical activity (LTPA) during pregnancy is associated with a reduced risk of preeclampsia, gestational diabetes mellitus (GDM), and preterm birth. However, these results are inconsistent when comparing cohort studies and randomized controlled trials (RCTs).

OBJECTIVE

The purpose of our study was to compare the associations between LTPA in pregnancy and maternal (GDM, preeclampsia, and weight gain during pregnancy) and child health outcomes (preterm birth, birthweight, and fetal growth) between RCTs and cohort studies.

METHODS

We performed a systematic search in PubMed, Web of Science, and EBSCO up to 31 August 2015. Inclusion criteria for experimental studies required randomized trials with a control group and exposure to a physical activity structured program. The inclusion criteria for cohort studies required information on LTPA during pregnancy as an exposure and at least one maternal-child health outcome. We assessed the methodological quality of all studies and performed a meta-analysis to produce summary estimates of the effects using random models.

RESULTS

We included 30 RCTs and 51 cohort studies. The meta-analysis of RCTs indicated that participation in LTPA was associated with lower weight gain during pregnancy, lower likelihood of GDM, and lower likelihood of delivering a large-for-gestational-age infant. Cohort studies indicated that participation in LTPA was associated with lower weight gain during pregnancy, lower likelihood of GDM, and lower risk of preterm delivery.

CONCLUSIONS

Our findings support the promotion of LTPA in pregnancy as a strategy to improve maternal and child health.

Associations of Diet and Physical Activity with Risk for Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis

Rising rates of gestational diabetes mellitus (GDM) and related complications have prompted calls to identify potentially modifiable risk factors that are associated with gestational diabetes mellitus (GDM). We systematically reviewed the scientific literature for observational studies examining specific dietary and/or physical activity (PA) factors and risk of GDM. Our search included PubMed, Medline, CINAHL/EBSCO, Science Direct and EMBASE, and identified 1167 articles, of which 40 met our inclusion criteria (e.g., singleton pregnancy, reported diet or PA data during pre-pregnancy/early pregnancy and GDM as an outcome measure). Studies were assessed for quality using a modified Quality Criteria Checklist from American Dietetic Association. Of the final 40 studies, 72% obtained a positive quality rating and 28% were rated neutral. The final analysis incorporated data on 30,871 pregnant women. Dietary studies were categorised into either caffeine, carbohydrate, fat, protein, calcium, fast food and recognized dietary patterns. Diets such as Mediterranean Diet (MedDiet), Dietary Approaches to Stop Hypertension (DASH) diet and Alternate Healthy Eating Index diet (AHEI) were associated with 15–38% reduced relative risk of GDM. In contrast, frequent consumption of potato, meat/processed meats, and protein (% energy) derived from animal sources was associated with an increased risk of GDM. Compared to no PA, any pre-pregnancy or early pregnancy PA was associated with 30% and 21% reduced odds of GDM, respectively. Engaging in >90 min/week of leisure time PA before pregnancy was associated with 46% decreased odds of GDM. We conclude that diets resembling MedDiet/DASH diet as well as higher PA levels before or in early pregnancy were associated with lower risks or odds of GDM respectively. The systematic review was registered at PROSPERO (www.crd.york.ac.uk/PROSPERO) as CRD42016027795.

Combined diet and exercise interventions for preventing gestational diabetes mellitus

BACKGROUND

Gestational diabetes mellitus (GDM) is associated with a wide range of adverse health consequences for women and their infants in the short and long term. With an increasing prevalence of GDM worldwide, there is an urgent need to assess strategies for GDM prevention, such as combined diet and exercise interventions. This is an update of a Cochrane review that was first published in 2015.

OBJECTIVES

To assess the effects of diet interventions in combination with exercise interventions for pregnant women for preventing GDM, and associated adverse health consequences for the mother and her infant/child.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (27 November 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and cluster-RCTs, comparing combined diet and exercise interventions with no intervention (i.e. standard care), that reported on GDM diagnosis as an outcome. Quasi-RCTs were excluded. Cross-over trials were not eligible for inclusion. We planned to include RCTs comparing two or more different diet/exercise interventions, however none were identified.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility, extracted data, assessed the risk of bias of the included trials and assessed quality of evidence for selected maternal and infant/child outcomes using the GRADE approach. We checked data for accuracy.

MAIN RESULTS

In this update, we included 23 RCTs (involving 8918 women and 8709 infants) that compared combined diet and exercise interventions with no intervention (standard care). The studies varied in the diet and exercise programs evaluated and health outcomes reported. None reported receiving funding from a drug manufacturer or agency with interests in the results. Overall risk of bias was judged to be unclear due to the lack of methodological detail reported. Most studies were undertaken in high-income countries.For our primary review outcomes, there was a possible reduced risk of GDM in the diet and exercise intervention group compared with the standard care group (average risk ratio (RR) 0.85, 95% confidence interval (CI) 0.71 to 1.01; 6633 women; 19 RCTs; Tau² = 0.05; I² = 42%; P = 0.07; moderate-quality evidence). There was also a possible reduced risk of caesarean section (RR 0.95, 95% CI 0.88 to 1.02; 6089 women; 14 RCTs; moderate-quality evidence). No clear differences were seen between groups for pre-eclampsia (RR 0.98, 95% CI 0.79 to 1.22; 5366 participants; 8 RCTs; low-quality evidence), pregnancy-induced hypertension and/or hypertension (average RR 0.78, 95% CI 0.47 to 1.27; 3073 participants; 6 RCTs; Tau² = 0.19; I² = 62%; very low-quality evidence), perinatal mortality (RR 0.82, 95% CI 0.42 to 1.63; 3757 participants; 2 RCTs; low-quality evidence) or large-for-gestational age (RR 0.93, 95% CI 0.81 to 1.07; 5353 participants; 11 RCTs; low-quality evidence). No data were reported for infant mortality or morbidity composite.Subgroup analyses (based on trial design, maternal body mass index (BMI) and ethnicity) revealed no clear differential treatment effects. We were unable to assess the impact of maternal age, parity and specific features of the diet and exercise interventions. Findings from sensitivity analyses (based on RCT quality) generally supported those observed in the main analyses. We were not able to perform subgroup analyses based on maternal age, parity or nature of the exercise/dietary interventions due to the paucity of information/data on these characteristics and the inability to meaningfully group intervention characteristics.For most of the secondary review outcomes assessed using GRADE, there were no clear differences between groups, including for perineal trauma (RR 1.27, 95% CI 0.78 to 2.05; 2733 participants; 2 RCTs; moderate-quality evidence), neonatal hypoglycaemia (average RR 1.42, 95% CI 0.67 to 2.98; 3653 participants; 2 RCTs; Tau² = 0.23; I² = 77%; low quality evidence); and childhood adiposity (BMI z score) (MD 0.05, 95% CI -0.29 to 0.40; 794 participants; 2 RCTs; Tau² = 0.04; I² = 59%; low-quality evidence). However, there was evidence of less gestational weight gain in the diet and exercise intervention group compared with the control group (mean difference (MD) -0.89 kg, 95% CI -1.39 to -0.40; 5052 women; 16 RCTs; Tau² = 0.37; I² = 43%;moderate-quality evidence). No data were reported for maternal postnatal depression or type 2 diabetes; childhood/adulthood type 2 diabetes, or neurosensory disability.

AUTHORS' CONCLUSIONS

Moderate-quality evidence suggests reduced risks of GDM and caesarean section with combined diet and exercise interventions during pregnancy as well as reductions in gestational weight gain, compared with standard care. There were no clear differences in hypertensive disorders of pregnancy, perinatal mortality, large-for-gestational age, perineal trauma, neonatal hypoglycaemia, and childhood adiposity (moderate- tovery low-quality evidence).Using GRADE methodology, the evidence was assessed as moderate to very low quality. Downgrading decisions were predominantly due to design limitations (risk of bias), and imprecision (uncertain effect estimates, and at times, small sample sizes and low event rates), however two outcomes (pregnancy-induced hypertension/hypertension and neonatal hypoglycaemia), were also downgraded for unexplained inconsistency (statistical heterogeneity).Due to the variability of the diet and exercise components tested in the included studies, the evidence in this review has limited ability to inform practice. Future studies could describe the interventions used in more detail, if and how these influenced behaviour change and ideally be standardised between studies. Studies could also consider using existing core outcome sets to facilitate more standardised reporting.

Insulin for the treatment of women with gestational diabetes

BACKGROUND

Gestational diabetes mellitus (GDM) is associated with short- and long-term complications for the mother and her infant. Women who are unable to maintain their blood glucose concentration within pre-specified treatment targets with diet and lifestyle interventions will require anti-diabetic pharmacological therapies. This review explores the safety and effectiveness of insulin compared with oral anti-diabetic pharmacological therapies, non-pharmacological interventions and insulin regimens.

OBJECTIVES

To evaluate the effects of insulin in treating women with gestational diabetes.

SEARCH METHODS

We searched Pregnancy and Childbirth's Trials Register (1 May 2017), ClinicalTrials.gov, WHO International Clinical Trials Registry Platform (ICTRP) (1 May 2017) and reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials (including those published in abstract form) comparing:a) insulin with an oral anti-diabetic pharmacological therapy;b) with a non-pharmacological intervention;c) different insulin analogues;d) different insulin regimens for treating women with diagnosed with GDM.We excluded quasi-randomised and trials including women with pre-existing type 1 or type 2 diabetes. Cross-over trials were not eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility, risk of bias, and extracted data. Data were checked for accuracy.

MAIN RESULTS

We included 53 relevant studies (103 publications), reporting data for 7381 women. Forty-six of these studies reported data for 6435 infants but our analyses were based on fewer number of studies/participants.Overall, the risk of bias was unclear; 40 of the 53 included trials were not blinded. Overall, the quality of the evidence ranged from moderate to very low quality. The primary reasons for downgrading evidence were imprecision, risk of bias and inconsistency. We report the results for our maternal and infant GRADE outcomes for the main comparison. Insulin versus oral anti-diabetic pharmacological therapyFor the mother, insulin was associated with an increased risk for hypertensive disorders of pregnancy (not defined) compared to oral anti-diabetic pharmacological therapy (risk ratio (RR) 1.89, 95% confidence interval (CI) 1.14 to 3.12; four studies, 1214 women; moderate-quality evidence). There was no clear evidence of a difference between those who had been treated with insulin and those who had been treated with an oral anti-diabetic pharmacological therapy for the risk of pre-eclampsia (RR 1.14, 95% CI 0.86 to 1.52; 10 studies, 2060 women; moderate-quality evidence); the risk of birth by caesarean section (RR 1.03, 95% CI 0.93 to 1.14; 17 studies, 1988 women; moderate-quality evidence); or the risk of developing type 2 diabetes (metformin only) (RR 1.39, 95% CI 0.80 to 2.44; two studies, 754 women; moderate-quality evidence). The risk of undergoing induction of labour for those treated with insulin compared with oral anti-diabetic pharmacological therapy may possibly be increased, although the evidence was not clear (average RR 1.30, 95% CI 0.96 to 1.75; three studies, 348 women; I² = 32%; moderate-quality of evidence). There was no clear evidence of difference in postnatal weight retention between women treated with insulin and those treated with oral anti-diabetic pharmacological therapy (metformin) at six to eight weeks postpartum (MD -1.60 kg, 95% CI -6.34 to 3.14; one study, 167 women; low-quality evidence) or one year postpartum (MD -3.70, 95% CI -8.50 to 1.10; one study, 176 women; low-quality evidence). The outcomes of perineal trauma/tearing or postnatal depression were not reported in the included studies.For the infant, there was no evidence of a clear difference between those whose mothers had been treated with insulin and those treated with oral anti-diabetic pharmacological therapies for the risk of being born large-for-gestational age (average RR 1.01, 95% CI 0.76 to 1.35; 13 studies, 2352 infants; moderate-quality evidence); the risk of perinatal (fetal and neonatal death) mortality (RR 0.85; 95% CI 0.29 to 2.49; 10 studies, 1463 infants; low-quality evidence);, for the risk of death or serious morbidity composite (RR 1.03, 95% CI 0.84 to 1.26; two studies, 760 infants; moderate-quality evidence); the risk of neonatal hypoglycaemia (average RR 1.14, 95% CI 0.85 to 1.52; 24 studies, 3892 infants; low-quality evidence); neonatal adiposity at birth (% fat mass) (mean difference (MD) 1.6%, 95% CI -3.77 to 0.57; one study, 82 infants; moderate-quality evidence); neonatal adiposity at birth (skinfold sum/mm) (MD 0.8 mm, 95% CI -2.33 to 0.73; random-effects; one study, 82 infants; very low-quality evidence); or childhood adiposity (total percentage fat mass) (MD 0.5%; 95% CI -0.49 to 1.49; one study, 318 children; low-quality evidence). Low-quality evidence also found no clear differences between groups for rates of neurosensory disabilities in later childhood: hearing impairment (RR 0.31, 95% CI 0.01 to 7.49; one study, 93 children), visual impairment (RR 0.31, 95% CI 0.03 to 2.90; one study, 93 children), or any mild developmental delay (RR 1.07, 95% CI 0.33 to 3.44; one study, 93 children). Later infant mortality, and childhood diabetes were not reported as outcomes in the included studies.We also looked at comparisons for regular human insulin versus other insulin analogues, insulin versus diet/standard care, insulin versus exercise and comparisons of insulin regimens, however there was insufficient evidence to determine any differences for many of the key health outcomes. Please refer to the main results for more information about these comparisons.

AUTHORS' CONCLUSIONS

The main comparison in this review is insulin versus oral anti-diabetic pharmacological therapies. Insulin and oral anti-diabetic pharmacological therapies have similar effects on key health outcomes. The quality of the evidence ranged from very low to moderate, with downgrading decisions due to imprecision, risk of bias and inconsistency.For the other comparisons of this review (insulin compared with non-pharmacological interventions, different insulin analogies or different insulin regimens), there is insufficient volume of high-quality evidence to determine differences for key health outcomes.Long-term maternal and neonatal outcomes were poorly reported for all comparisons.The evidence suggests that there are minimal harms associated with the effects of treatment with either insulin or oral anti-diabetic pharmacological therapies. The choice to use one or the other may be down to physician or maternal preference, availability or severity of GDM. Further research is needed to explore optimal insulin regimens. Further research could aim to report data for standardised GDM outcomes.

Associations of physical activity and sedentary behavior during pregnancy with gestational diabetes mellitus among Asian women in Singapore

BACKGROUND

Few studies have investigated physical activity (PA) and sedentary behavior (SB) in relation to fasting (FG) and 2-h postprandial plasma glucose (2hPG) levels and gestational diabetes mellitus (GDM); we investigated these associations among Asian pregnant women.

METHODS

As part of the Growing Up in Singapore Towards healthy Outcomes cohort study, PA and SB (sitting and television times) were assessed by interviewer-administered questionnaire. During 75 g oral glucose tolerance tests at 26-28 weeks' gestation we measured FG, 2hPG levels and GDM (FG ≥ 7.0 mmol/L and/or 2hPG ≥ 7.8 mmol/L). Associations were analysed by multiple linear and logistic regression.

RESULTS

Among the 1083 women studied, 18.6% had GDM. SB was not associated with FG, 2hPG and GDM. Higher categories of PA were associated with lower 2hPG and a lower likelihood of GDM (p-trend < 0.05), but not with FG levels. Compared to insufficiently active women, highly active women had lower 2hPG levels [β (95% CI): -0.32 (-0.59, -0.05), p = 0.020) and were less likely to have GDM [OR: 0.56 (0.32-0.98), p = 0.040]. Stratified analysis revealed no associations among under/normal-weight women, but significant associations among overweight/obese women; in those with BMI ≥23 kg/m2, sufficiently active and highly active women were less likely to have GDM [OR: 0.52, (0.29-0.93), p = 0.028, and OR: 0.34, (0.15-0.77), p = 0.010, respectively].

CONCLUSION

Higher PA was associated with lower 2hPG levels and a lower prevalence of GDM, particularly in overweight/obese women. Further studies are warranted to confirm these findings, and to examine the effectiveness of PA promotion strategies for the prevention of gestational hyperglycemia.

Leisure Time Physical Activity and Gestational Diabetes Mellitus in the Omega Study

PURPOSE

Findings of studies investigating associations of leisure time physical activity (LTPA) with gestational diabetes mellitus (GDM) risk have been inconsistent. We investigated associations of LTPA with GDM and whether these associations differ by prepregnancy overweight/obese status or gestational weight gain category.

METHODS

Participants (N = 3209) of the Omega study, a pregnancy cohort study in Washington State (1996-2008), reported LTPA duration (h·wk) and energy expenditure (MET·h·wk) in the year before pregnancy and in early pregnancy. Diagnoses of GDM were abstracted from medical records. Poisson regression models were used to determine relative risks of GDM across tertiles of prepregnancy or early pregnancy LTPA duration and energy expenditure. Stratified analyses and interaction terms were used to assess effect modification by prepregnancy overweight/obese status (BMI ≥25 kg·m) or gestational weight gain category (adequate or excessive).

RESULTS

Each tertile increase in prepregnancy LTPA duration or energy expenditure was associated with 15% (95% CI = 0.72-1.00) and 19% (95% CI = 0.69-0.96) lower risk of GDM, respectively. Each tertile increase in early pregnancy LTPA duration or energy expenditure was associated with 16% (95% CI = 0.72-0.97) and 17% (95% CI = 0.72-0.95) lower risk of GDM, respectively. LTPA during both prepregnancy and early pregnancy was associated with a 46% reduced risk of GDM (95% CI = 0.32-0.89) compared with inactivity during both periods. LTPA-GDM associations were similar by prepregnancy BMI and gestational weight gain.

CONCLUSION

Our results support a role for the promotion of physical activity before and during pregnancy in the prevention of GDM.

Exercise for pregnant women with gestational diabetes for improving maternal and fetal outcomes

BACKGROUND

Gestational diabetes mellitus (GDM) is associated with both short- and long-term complications for the mother and her baby. Exercise interventions may be useful in helping with glycaemic control and improve maternal and infant outcomes.The original review on Exercise for diabetic pregnant women has been split into two new review titles reflecting the role of exercise for pregnant women with gestational diabetes and for pregnant women with pre-existing diabetes. Exercise for pregnant women with gestational diabetes for improving maternal and fetal outcomes (this review) Exercise for pregnant women with pre-existing diabetes for improving maternal and fetal outcomes OBJECTIVES: To evaluate the effects of exercise interventions for improving maternal and fetal outcomes in women with GDM.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (27 August 2016), ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (18th August 2016), and reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing an exercise intervention with standard care or another intervention in pregnant women diagnosed with gestational diabetes. Quasi-randomised and cross-over studies, and studies including women with pre-existing type 1 or type 2 diabetes were not eligible for inclusion.

DATA COLLECTION AND ANALYSIS

All selection of studies, assessment of trial quality and data extraction was conducted independently by two review authors. Data were checked for accuracy.

MAIN RESULTS

We included 11 randomised trials, involving 638 women. The overall risk of bias was judged to be unclear due to lack of methodological detail in the included studies.For the mother, there was no clear evidence of a difference between women in the exercise group and those in the control group for the risk of pre-eclampsia as the measure of hypertensive disorders of pregnancy (risk ratio (RR) 0.31, 95% confidence interval (CI) 0.01 to 7.09; two RCTs, 48 women; low-quality evidence), birth by caesarean section (RR 0.86, 95% CI 0.63 to 1.16; five RCTs, 316 women; I2 = 0%; moderate-quality evidence), the risk of induction of labour (RR 1.38, 95% CI 0.71 to 2.68; one RCT, 40 women; low-quality evidence) or maternal body mass index at follow-up (postnatal weight retention or return to pre-pregnancy weight) (mean difference (MD) 0.11 kg/m2, 95% CI -1.04 to 1.26; three RCTs, 254 women; I2 = 0%; high-quality evidence). Development of type 2 diabetes, perineal trauma/tearing and postnatal depression were not reported as outcomes in the included studies.For the infant/child/adult, a single small (n = 19) trial reported no perinatal mortality (stillbirth and neonatal mortality) events in either the exercise intervention or control group (low-quality evidence). There was no clear evidence of a difference between groups for a mortality and morbidity composite (variously defined by trials, e.g. perinatal or infant death, shoulder dystocia, bone fracture or nerve palsy) (RR 0.56, 95% CI 0.12 to 2.61; two RCTs, 169 infants; I2 = 0%; moderate-quality evidence) or neonatal hypoglycaemia (RR 2.00, 95% CI 0.20 to 20.04; one RCT, 34 infants; low-quality evidence). None of the included trials pre-specified large-for-gestational age, adiposity (neonatal/infant, childhood or adulthood), diabetes (childhood or adulthood) or neurosensory disability (neonatal/infant) as trial outcomes.Other maternal outcomes of interest: exercise interventions were associated with both reduced fasting blood glucose concentrations (average standardised mean difference (SMD) -0.59, 95% CI -1.07 to -0.11; four RCTs, 363 women; I2 = 73%; T2 = 0.19) and a reduced postprandial blood glucose concentration compared with control interventions (average SMD -0.85, 95% CI -1.15 to -0.55; three RCTs, 344 women; I2 = 34%; T2 = 0.03).

AUTHORS' CONCLUSIONS

Short- and long-term outcomes of interest for this review were poorly reported. Current evidence is confounded by the large variety of exercise interventions. There was insufficient high-quality evidence to be able to determine any differences between exercise and control groups for our outcomes of interest. For the woman, both fasting and postprandial blood glucose concentrations were reduced compared with the control groups. There are currently insufficient data for us to determine if there are also benefits for the infant. The quality of the evidence in this review ranged from high to low quality and the main reason for downgrading was for risk of bias and imprecision (wide CIs, low event rates and small sample size). Development of type 2 diabetes, perineal trauma/tearing, postnatal depression, large-for-gestational age, adiposity (neonate/infant, childhood or adulthood), diabetes (childhood or adulthood) or neurosensory disability (neonate/infant) were not reported as outcomes in the included studies.Further research is required comparing different types of exercise interventions with control groups or with another exercise intervention that reports on both the short- and long-term outcomes (for both the mother and infant/child) as listed in this review.

Lifestyle interventions for the treatment of women with gestational diabetes

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

Different types of dietary advice for women with gestational diabetes mellitus

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

Oral anti-diabetic pharmacological therapies for the treatment of women with gestational diabetes

BACKGROUND

Gestational diabetes mellitus (GDM) is a major public health issue with rates increasing globally. Gestational diabetes, glucose intolerance first recognised during pregnancy, usually resolves after birth and is associated with short- and long-term complications for the mother and her infant. Treatment options can include oral anti-diabetic pharmacological therapies.

OBJECTIVES

To evaluate the effects of oral anti-diabetic pharmacological therapies for treating women with GDM.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (14 May 2016), ClinicalTrials.gov, WHO ICTRP (14 May 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

We included published and unpublished randomised controlled trials assessing the effects of oral anti-diabetic pharmacological therapies for treating pregnant women with GDM. We included studies comparing oral anti-diabetic pharmacological therapies with 1) placebo/standard care, 2) another oral anti-diabetic pharmacological therapy, 3) combined oral anti-diabetic pharmacological therapies. Trials using insulin as the comparator were excluded as they are the subject of a separate Cochrane systematic review.Women with pre-existing type 1 or type 2 diabetes were excluded.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and trial quality. Two review authors independently extracted data and data were checked for accuracy.

MAIN RESULTS

We included 11 studies (19 publications) (1487 women and their babies). Eight studies had data that could be included in meta-analyses. Studies were conducted in Brazil, India, Israel, UK, South Africa and USA. The studies varied in diagnostic criteria and treatment targets for glycaemic control for GDM. The overall risk of bias was 'unclear' due to inadequate reporting of methodology. Using GRADE the quality of the evidence ranged from moderate to very low quality. Evidence was downgraded for risk of bias (reporting bias, lack of blinding), inconsistency, indirectness, imprecision and for oral anti-diabetic therapy versus placebo for generalisability. Oral anti-diabetic pharmacological therapies versus placebo/standard careThere was no evidence of a difference between glibenclamide and placebo groups for hypertensive disorders of pregnancy (risk ratio (RR) 1.24, 95% confidence interval (CI) 0.81 to 1.90; one study, 375 women, very low-quality evidence), birth by caesarean section (RR 1.03, 95% CI 0.79 to 1.34; one study, 375 women, very low-quality evidence), perineal trauma (RR 0.98, 95% CI 0.06 to 15.62; one study, 375 women, very low-quality evidence) or induction of labour (RR 1.18, 95% CI 0.79 to 1.76; one study, 375 women; very low-quality evidence). No data were reported for development of type 2 diabetes or other pre-specified GRADE maternal outcomes (return to pre-pregnancy weight, postnatal depression). For the infant, there was no evidence of a difference in the risk of being born large-for-gestational age (LGA) between infants whose mothers had been treated with glibenclamide and those in the placebo group (RR 0.89, 95% CI 0.51 to 1.58; one study, 375, low-quality evidence). No data were reported for other infant primary or GRADE outcomes (perinatal mortality, death or serious morbidity composite, neurosensory disability in later childhood, neonatal hypoglycaemia, adiposity, diabetes). Metformin versus glibenclamideThere was no evidence of a difference between metformin- and glibenclamide-treated groups for the risk of hypertensive disorders of pregnancy (RR 0.70, 95% CI 0.38 to 1.30; three studies, 508 women, moderate-quality evidence), birth by caesarean section (average RR 1.20, 95% CI 1.20; 95% CI 0.83 to 1.72, four studies, 554 women, I2 = 61%, Tau2 = 0.07 low-quality evidence), induction of labour (0.81, 95% CI 0.61 to 1.07; one study, 159 women; low-quality evidence) or perineal trauma (RR 1.67, 95% CI 0.22 to 12.52; two studies, 158 women; low-quality evidence). No data were reported for development of type 2 diabetes or other pre-specified GRADE maternal outcomes (return to pre-pregnancy weight, postnatal depression). For the infant there was no evidence of a difference between the metformin- and glibenclamide-exposed groups for the risk of being born LGA (average RR 0.67, 95% CI 0.24 to 1.83; two studies, 246 infants, I2 = 54%, Tau2 = 0.30 low-quality evidence). Metformin was associated with a decrease in a death or serious morbidity composite (RR 0.54, 95% CI 0.31 to 0.94; one study, 159 infants, low-quality evidence). There was no clear difference between groups for neonatal hypoglycaemia (RR 0.86, 95% CI 0.42 to 1.77; four studies, 554 infants, low-quality evidence) or perinatal mortality (RR 0.92, 95% CI 0.06 to 14.55, two studies, 359 infants). No data were reported for neurosensory disability in later childhood or for adiposity or diabetes. Glibenclamide versus acarboseThere was no evidence of a difference between glibenclamide and acarbose from one study (43 women) for any of their maternal or infant primary outcomes (caesarean section, RR 0.95, 95% CI 0.53 to 1.70; low-quality evidence; perinatal mortality - no events; low-quality evidence; LGA , RR 2.38, 95% CI 0.54 to 10.46; low-quality evidence). There was no evidence of a difference between glibenclamide and acarbose for neonatal hypoglycaemia (RR 6.33, 95% CI 0.87 to 46.32; low-quality evidence). There were no data reported for other pre-specified GRADE or primary maternal outcomes (hypertensive disorders of pregnancy, development of type 2 diabetes, perineal trauma, return to pre-pregnancy weight, postnatal depression, induction of labour) or neonatal outcomes (death or serious morbidity composite, adiposity or diabetes).

AUTHORS' CONCLUSIONS

There were insufficient data comparing oral anti-diabetic pharmacological therapies with placebo/standard care (lifestyle advice) to inform clinical practice. There was insufficient high-quality evidence to be able to draw any meaningful conclusions as to the benefits of one oral anti-diabetic pharmacological therapy over another due to limited reporting of data for the primary and secondary outcomes in this review. Short- and long-term clinical outcomes for this review were inadequately reported or not reported. Current choice of oral anti-diabetic pharmacological therapy appears to be based on clinical preference, availability and national clinical practice guidelines.The benefits and potential harms of one oral anti-diabetic pharmacological therapy compared with another, or compared with placebo/standard care remains unclear and requires further research. Future trials should attempt to report on the core outcomes suggested in this review, in particular long-term outcomes for the woman and the infant that have been poorly reported to date, women's experiences and cost benefit.

Primary prevention of gestational diabetes mellitus through nutritional factors: a systematic review

BACKGROUND

Gestational diabetes mellitus (GDM), defined as any degree of glucose intolerance with onset during pregnancy, is increasing worldwide, mostly because obesity among women of reproductive age is continuously escalating. GDM is associated with adverse maternal and fetal outcomes. The aim of this article was to systematically review literature on the effectiveness of nutritional factors before or during pregnancy to prevent GDM.

METHODS

We assessed the primary prevention of GDM through nutritional factors, as diet and supplements. We searched on PubMed, Cochrane Databases and ClinicalTrials.gov from inception to June 2016. Clinical trials and adjusted prospective cohort studies were included.

RESULTS

Eight clinical trials and twenty observational studies assessing the association between dietary factors and primary prevention of GDM were included. Furthermore, six clinical trials and two observational studies related to supplements were also added. Only two nutritional interventions were found to significantly reduce the incidence of GDM, besides the supplements. However, the observational studies showed that a higher adherence to a healthier dietary pattern can prevent the incidence of GDM, especially in high risk population before getting pregnant.

CONCLUSIONS

The results indicate that there may be some benefits of some nutritional factors to prevent GDM. However, better-designed studies are required to generate higher quality evidence. At the moment, no strong conclusions can be drawn with regard to the best intervention for the prevention of GDM.

Physical activity and the risk of gestational diabetes mellitus: a systematic review and dose-response meta-analysis of epidemiological studies

Physical activity has been inconsistently associated with risk of gestational diabetes mellitus in epidemiological studies, and questions remain about the strength and shape of the dose-response relationship between the two. We therefore conducted a systematic review and meta-analysis of cohort studies and randomized trials on physical activity and gestational diabetes mellitus. PubMed, Embase and Ovid databases were searched for cohort studies, and randomized controlled trials of physical activity and risk of gestational diabetes mellitus, up to August 5th 2015. Summary relative risks (RRs) were estimated using a random effects model. Twenty-five studies (26 publications) were included. For total physical activity the summary RR for high versus low activity was 0.62 (95 % CI 0.41-0.94, I2 = 0 %, n = 4) before pregnancy, and 0.66 (95 % CI 0.36-1.21, I2 = 0 %, n = 3) during pregnancy. For leisure-time physical activity the respective summary RRs for high versus low activity was 0.78 (95 % CI 0.61-1.00, I2 = 47 %, n = 8) before pregnancy, and it was 0.80 (95 % CI 0.64-1.00, I2 = 17 %, n = 17) during pregnancy. The summary RR for pre-pregnancy activity was 0.70 (95 % CI 0.49-1.01, I2 = 72.6 %, n = 3) per increment of 5 h/week and for activity during pregnancy was 0.98 (95 % CI 0.87-1.09, I2 = 0 %, n = 3) per 5 h/week. There was evidence of a nonlinear association between physical activity before pregnancy and the risk of gestational diabetes mellitus, pnonlinearity = 0.005, with a slightly steeper association at lower levels of activity although further reductions in risk were observed up to 10 h/week. There was also evidence of nonlinearity for physical activity in early pregnancy, pnonlinearity = 0.008, with no further reduction in risk above 8 h/week. There was some indication of inverse associations between walking (before and during pregnancy) and vigorous activity (before pregnancy) and the risk of gestational diabetes mellitus. This meta-analysis suggests that there is a significant inverse association between physical activity before pregnancy and in early pregnancy and the risk of gestational diabetes mellitus. Further studies are needed to clarify the association between specific types and intensities of activity and gestational diabetes mellitus.

What helps or hinders midwives to implement physical activity guidelines for obese pregnant women? A questionnaire survey using the Theoretical Domains Framework

OBJECTIVE

to investigate barriers and facilitators to physical activity (PA) guideline implementation for midwives when advising obese pregnant women.

DESIGN

a cross-sectional, self-completion, anonymous questionnaire was designed using the Theoretical Domains Framework. this framework was developed to evaluate the implementation of guidelines by health care professionals. A total of 40 questions were included. These were informed by previous research on pregnant women's and midwives views, knowledge and attitudes to PA, and supported by national evidence based guidelines. Demographic information and free text comments were also collected.

SETTING

three diverse NHS Trusts in the North East of England.

PARTICIPANTS

all midwives employed by two hospital Trusts and the community midwives from the third Trust (n=375) were invited to participate.

MEASUREMENTS

mean domain scores were calculated. Factor and regression analysis were performed to describe which theoretical domains may be influencing practice. Free text comments were analysed thematically.

FINDINGS

192 (53%) questionnaires were returned. Mean domain scores were highest for social professional role and knowledge, and lowest for skills, beliefs about capabilities and behaviour regulation. Regression analysis indicated that skills and memory/attention/decision domains had a statistically significant influence on midwives discussing PA with obese pregnant women and advising them accordingly. Midwives comments indicated that they felt it was part of their role to discuss PA with all pregnant women but felt they lacked the skills and resources to do so effectively.

KEY CONCLUSIONS

midwives seem to have the necessary knowledge about the need/importance of PA advice for obese women and believe it is part of their role, but perceive they lack necessary skills and resources, and do not plan or prioritise the discussion regarding PA with obese pregnant woman.

IMPLICATIONS FOR PRACTICE

designing interventions that improve skills, promote routine enquiry regarding PA and provide resources (eg. information, referral pathways) may help improve midwives' PA advice.

The Association Between Physical Activity During Pregnancy and Gestational Diabetes Mellitus: A Case-Control Study

BACKGROUND

Gestational diabetes mellitus is one of the most common complications of pregnancy. Physical activity is associated with a lower risk of type 2 diabetes mellitus. A recent meta-analysis study suggested that more research is needed to investigate the type, duration and intensity of physical activity that can help to reduce the risk of gestational diabetes mellitus.

OBJECTIVES

The present study aimed to understand the association between physical activity and gestational diabetes mellitus through comparing the type and intensity of physical activity performed by pregnant females with gestational diabetes and healthy pregnant females in the first 20 weeks of their pregnancy.

PATIENTS AND METHODS

In the current case-control study, 100 pregnant females with gestational diabetes mellitus as the case group and 100 pregnant females as the non-diabetic control group were recruited. The age range of the participants was 18 - 40 years with the gestation of 20 - 28 weeks. To diagnose gestational diabetes mellitus using the criteria introduced by carpenter and coustan females with abnormal glucose challenge test (> 140 mg/dL) were asked to perform the three-hour 100 g oral glucose tolerance test. The details of physical activity were collected by a modified version of the pregnancy physical activity questionnaire. Anthropometric and relevant data were recorded for all of the participants. Data were analyzed by SPSS version 21. Risk estimates were obtained by logistic regression and adjusted for confounders.

RESULTS

Females who had low total physical activity according to the pregnancy physical activity questionnaire during early pregnancy were at a significantly higher risk of developing gestational diabetes mellitus (OR = 4.12, 95% CI (2.28 - 7.43), P = 0.001) compared to the ones who reported higher levels of physical activity. Moreover, after adjusting for age, body mass index (BMI), gravidity and a family history of diabetes, females with low physical activity in the domain of transportation activity during 20 weeks of pregnancy were at a significantly higher risk of developing gestational diabetes mellitus. The statistical findings indicate that females with the low intensity of sedentary, light and moderate physical activity are at a higher risk of developing gestational diabetes mellitus (OR 2.32; 95% CI 1.21-4.43, P = 0.010, OR 6.26; 95% CI 2.95 - 13.30, P = 0.001 and OR 6.73; 95% CI 3.15 - 14.38, P = 0.001) compared to females with a higher intensity of sedentary, light and moderate physical activity.

CONCLUSIONS

The amount and intensity of physical activity during pregnancy is associated with a lower risk of gestational diabetes mellitus. As a result, the pregnant Iranian females have to be encouraged to do regular daily physical activity during pregnancy, if there is no specific contraindication to it.

Diet and exercise interventions for preventing gestational diabetes mellitus

BACKGROUND

Gestational diabetes mellitus (GDM) is associated with a wide range of adverse health consequences for women and their babies in the short and long term. With an increasing prevalence of GDM worldwide, there is an urgent need to assess strategies for GDM prevention, such as combined diet and exercise interventions.

OBJECTIVES

To assess the effects of combined diet and exercise interventions for preventing GDM and associated adverse health consequences for women and their babies.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (11 February 2014) and reference lists of retrieved studies. We updated the search in February 2015 but these results have not yet been incorporated and are awaiting classification.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and cluster-RCTs assessing the effects of interventions that included diet and exercise components. We included studies where combined diet and exercise interventions were compared with no intervention (i.e. standard care).We planned to also compare diet and exercise interventions with alternative diet and/or exercise interventions but no trials were identified for this comparison.

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.

MAIN RESULTS

We included 13 randomised controlled trials (involving 4983 women and their babies). We assessed the included trials as being of moderate risk of bias overall.When comparing women receiving a diet and exercise intervention with those receiving no intervention, there was no clear difference in the risk of developing GDM (average risk ratio (RR) 0.92, 95% confidence interval (CI) 0.68 to 1.23; 11 trials, 3744 women), caesarean section (RR 0.92, 95% CI 0.83 to 1.01; seven trials, 3246 women), or large-for-gestational age (RR 0.90, 95% CI 0.77 to 1.05; 2950 infants). Only one trial reported on perinatal mortality, and found no clear difference in the risk of stillbirth (RR 0.99, 95% CI 0.29 to 3.42; 2202 fetuses) or neonatal death (RR 0.99, 95% CI 0.06 to 15.85; 2202 neonates).Very few differences were shown between groups for the review's secondary outcomes, including for induction of labour, perineal trauma, pre-eclampsia, postpartum haemorrhage and infection, macrosomia, birthweight, small-for-gestational age, ponderal index, neonatal hypoglycaemia requiring treatment, hyperbilirubinaemia requiring treatment, shoulder dystocia, bone fracture or nerve palsy. Women receiving a combined diet and exercise intervention were, however, found to have a reduced risk of preterm birth compared with women receiving no intervention (RR 0.71, 95% CI 0.55 to 0.93; five trials, 2713 women).A trend towards reduced weight gain during pregnancy was shown for women receiving the combined diet and exercise intervention (mean difference (MD) -0.76 kg, 95% CI -1.55 to 0.03; eight trials, 2707 women; P = 0.06, random-effects); but no clear difference in postnatal weight retention was observed overall.In relation to adherence to the interventions, a number of trials that reported on behaviour modifications showed benefits in diet- (5/8 trials) and physical activity- (4/8 trials) related behaviours for women receiving the combined diet and exercise intervention, compared with women receiving no intervention; however there was notable variation across trials in outcomes measured and results observed. Only two trials reported on well-being and quality of life of women, and did not observe differences between groups for these outcomes.Very few trials reported on outcomes relating to the use of health services, although one trial suggested a reduced length of antenatal hospital stay for women receiving a combined diet and exercise intervention (MD -0.27 days, 95% CI -0.49 to -0.05; 2153 women).No information was available on outcomes for the infant as a child or adult, or for most longer-term outcomes for the mother.

AUTHORS' CONCLUSIONS

There are limitations associated with the available RCT evidence on the effects of combined diet and exercise interventions during pregnancy for preventing GDM. Results from 13 RCTs (of moderate quality) suggest no clear difference in the risk of developing GDM for women receiving a combined diet and exercise intervention compared with women receiving no intervention. However, the ability to draw firm conclusions was limited by variations in the quality of trials, characteristics of the interventions and populations assessed, and outcome definitions between trials.Based on the data currently available, conclusive evidence is not available to guide practice. Further large, well-designed RCTs, addressing the limitations of previous studies, are needed to assess the effects of combined interventions on preventing GDM and other relevant pregnancy outcomes including caesarean birth, large-for-gestational age and perinatal mortality. Health service utilisation and costs, and longer-term outcomes for mothers and their babies should be included. We identified another 16 trials which are ongoing and we will consider these for inclusion in the next update of this review.

Changing trends in management of gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is on the rise globally. In view of the increasing prevalence of GDM and fetal and neonatal complications associated with it, there is a splurge of research in this field and management of GDM is undergoing a sea change. Trends are changing in prevention, screening, diagnosis, treatment and future follow up. There is emerging evidence regarding use of moderate exercise, probiotics and vitamin D in the prevention of GDM. Regarding treatment, newer insulin analogs like aspart, lispro and detemir are associated with better glycemic control than older insulins. Continuous glucose monitoring systems and continuous subcutaneous insulin systems may play a role in those who require higher doses of insulin for sugar control. Evidence exists that favors metformin as a safer alternative to insulin in view of good glycemic control and better perinatal outcomes. As the risk of developing GDM in subsequent pregnancies and also the risk of overt diabetes in later life is high, regular assessment of these women is required in future. Lifestyle interventions or metformin should be offered to women with a history of GDM who develop pre-diabetes. Further studies are required in the field of prevention of GDM for optimizing obstetric outcome.

The first trimester: prediction and prevention of the great obstetrical syndromes

A number of groups are currently examining the potential of screening for pre-eclampsia and gestational diabetes at 12 weeks' gestation. This can be performed at the time of combined first-trimester screening for aneuploidy using a similar method of regression analysis to combine multiple demographic and investigative factors. At present, research into the prediction of pre-eclampsia is more robust and is associated with the potential for therapeutic intervention that can reduce the prevalence of early-onset pre-eclampsia and improve maternal and neonatal outcomes.

Physical activity before and during pregnancy and risk of abnormal glucose tolerance among Hispanic women

AIM

Women diagnosed with abnormal glucose tolerance and gestational diabetes mellitus are at increased risk for subsequent type 2 diabetes, with higher risks in Hispanic women. Studies suggest that physical activity may be associated with a reduced risk of these disorders; however, studies in Hispanic women are sparse.

METHODS

We prospectively evaluated this association among 1241 Hispanic participants in Proyecto Buena Salud. The Pregnancy Physical Activity Questionnaire was used to assess pre, early, and mid pregnancy physical activity. Medical records were abstracted for pregnancy outcomes.

RESULTS

A total of 175 women (14.1%) were diagnosed with abnormal glucose tolerance and 57 women (4.6%) were diagnosed with gestational diabetes. Increasing age and body mass index were strongly and positively associated with risk of gestational diabetes. We did not observe statistically significant associations between total physical activity or meeting exercise guidelines and risk. However, after adjusting for age, BMI, gestational weight gain, and other important risk factors, women in the top quartile of moderate-intensity activity in early pregnancy had a decreased risk of abnormal glucose tolerance (odds ratio=0.48, 95% Confidence Interval 0.27-0.88, Ptrend=0.03) as compared to those in the lowest quartile. Similarly, women with the highest levels of occupational activity in early pregnancy had a decreased risk of abnormal glucose tolerance (odds ratio=0.48, 95% Confidence Interval 0.28-0.85, Ptrend=0.02) as compared to women who were unemployed.

CONCLUSION

In this Hispanic population, total physical activity and meeting exercise guidelines were not associated with risk. However, high levels of moderate-intensity and occupational activity were associated with risk reduction.

Preventing obesity: exercise and daily activities of low-income pregnant women

Low-income women are at risk for excessive gestational weight gain. Inactive lifestyle and lack of regular moderate exercise may contribute to the risk of weight gain. This study was conducted to (1) determine the rate and characteristics of low-income pregnant women who exercised regularly and met the American College of Obstetricians and Gynecologists recommendation and (2) describe how these women spent time for other physical activities compared with those who did not exercise regularly. Medicaid-recipient or uninsured pregnant women (n = 816) were asked to complete a physical activity questionnaire at rural and urban county health departments located in North Carolina. Twenty percent of low-income women met the American College of Obstetricians and Gynecologists recommendation for moderate exercise (≥10 METs-h/wk [metabolic equivalent task-hours per week]). The women who met the recommendation spent 3 hours 45 minutes per week walking as exercise, whereas those who did not meet the recommendation spent 1 hour per week (P < .0001). Women who exercised regularly spent longer hours at work (4.25 vs. 1.75 hours per day; P = .019) and on household tasks (5.25 vs. 4.0 hours per day; P = .002) than women who did not exercise regularly. Time spent on domestic and occupation activities does not seem to prohibit low-income women from engaging in moderate exercise on a regular basis.

Supervised exercise-based intervention to prevent excessive gestational weight gain: a randomized controlled trial

OBJECTIVE

To study the effect on maternal weight gain of a supervised light- to moderate-intensity exercise-based intervention performed from the ninth week of pregnancy.

PARTICIPANTS AND METHODS

A total of 962 healthy pregnant women were randomly assigned to a standard care or exercise intervention group conducted between September 1, 2007, and January 31, 2011. The intervention included light- to moderate-intensity aerobic and resistance exercises performed 3 days a week (50-55 minutes per session). Excessive gestational weight gain was calculated on the basis of the 2009 Institute of Medicine (IOM) recommendations. Gestational body weight gain was calculated on the basis of the weight measured at the first prenatal visit (fifth to sixth weeks of gestation) and weight measured at the last visit to the clinic before delivery. Women were categorized into normal weight or overweight or obese.

RESULTS

Women in the intervention group gained less weight (adjusted mean difference, 1.039 kg; 95% CI, 0.534-1.545 kg; P<.001) and were less likely to gain weight above the IOM recommendations (odds ratio, 0.625; 95% CI, 0.461-0.847) compared with those in the standard care group. The main treatment effects according to body mass index category were that normal weight women in the intervention group gained less weight (adjusted mean difference, 1.393 kg; 95% CI, 0.813-1.972 kg; P<.001) and were less likely to gain weight above the IOM recommendations (odds ratio, 0.508; 95% CI, 0.334-0.774) than normal weight women who received standard care. No significant treatment effect was observed in overweight or obese women.

CONCLUSION

Supervised exercise of light to moderate intensity can be used to prevent excessive gestational weight gain, especially in normal weight women.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01790347.

Physical activity during pregnancy and the risk of gestational diabetes mellitus: a systematic review and meta-analysis of randomised controlled trials

OBJECTIVES

We performed a systematic review and meta-analysis to assess the effects of physical activity in preventing gestational diabetes mellitus (GDM).

SEARCH STRATEGY

We searched the literature in six electronic databases and bibliographies of relevant articles.

SELECTION CRITERIA

We included randomised controlled trials on pregnant women who did not have GDM and other complications previously and had increased physical activity as the only intervention. The risk of developing GDM was documented separately for the intervention and control groups.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data and assessed quality independently. Data from the included trials were combined using a fixed-effects model. The effect size was expressed as relative risk (RR) and 95% CI.

MAIN RESULTS

Of the 1110 studies identified, six randomised controlled trials met the inclusion criteria. In three trials, the incidence of GDM was lower in the intervention group than in the control group, whereas two trials showed a higher incidence of GDM in the intervention group and the remaining trial found no GDM in either the intervention or control group. The meta-analysis resulted in a relative risk (RR) of GDM of 0.91 (95% CI 0.57 to 1.44), suggesting no significant difference in the risk of developing GDM between the intervention and the control groups. No indication of publication bias was found.

CONCLUSIONS

Evidence was insufficient to suggest that physical activity during pregnancy might be effective to lower the risk of developing GDM.

Different types of dietary advice for women with gestational diabetes mellitus

BACKGROUND

Gestational diabetes mellitus (GDM) affects a significant number of women each year and is associated with a wide range of adverse outcomes for women and their babies. Dietary counselling is the main strategy in managing GDM, but it remains unclear which dietary therapy is best.

OBJECTIVES

To assess the effects of different types of dietary advice for women with GDM on pregnancy outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (17 May 2012) and the WOMBAT Perinatal Trials Registry (17 April 2012).

SELECTION CRITERIA

Randomised controlled trials (RCTs) and cluster-RCTs assessing the effects of different types of dietary advice for women with GDM on pregnancy outcomes.We intended to compare two or more forms of the same type of dietary advice against each other, i.e. standard dietary advice compared with individualised dietary advice, individual dietary education sessions compared with group dietary education sessions. We intended to compare different intensities of dietary intervention with each other, i.e. single dietary counselling session compared with multiple dietary counselling sessions.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility, extracted data and assessed risk of bias of included studies. Data were checked for accuracy.

MAIN RESULTS

We included nine trials; 429 women (436 babies) provided outcome data. All nine included trials had small sample sizes with variation in levels of risk of bias. A total of 11 different types of dietary advice were assessed under six different comparisons, including:low-moderate glycaemic index (GI) food versus high-moderate GI food, low-GI diet versus high-fibre moderate-GI diet, energy-restricted diet versus no energy restriction diet, low-carbohydrate diet (≤ 45% daily total energy intake from carbohydrate) versus high-carbohydrate diet (≥ 50% daily total energy intake from carbohydrate), high-monounsaturated fat diet (at least 20% total energy from monounsaturated fat) versus high-carbohydrate diet (at least 50% total energy from carbohydrate), standard-fibre diet (American Diabetes Association (ADA) diet) (20 grams fibre/day) versus fibre-enriched diet (80 grams fibre/day).In the low-moderate GI food versus moderate-high GI food comparison, no significant differences were seen for macrosomia or large-for-gestational age (LGA), (two trials, 89 babies) (risk ratio (RR) 0.45, 95% confidence interval (CI) 0.10 to 2.08), (RR 0.95, 95% CI 0.27 to 3.36), respectively; or caesarean section (RR 0.66, 95% CI 0.29 to 1.47, one trial, 63 women).In the low-GI diet versus high-fibre moderate-GI diet comparison, no significant differences were seen for macrosomia or LGA (one trial, 92 babies) (RR 0.32, 95% CI 0.03 to 2.96), (RR 2.87, 95% CI 0.61 to 13.50), respectively; or caesarean section (RR 1.80, 95% CI 0.66 to 4.94, one trial, 88 women).In the energy-restricted versus unrestricted diet comparison, no significant differences were seen for macrosomia (RR 1.56, 95% CI 0.61 to 3.94, one trial, 122 babies); LGA (RR 1.17, 95% CI 0.65 to 2.12, one trial, 123 babies); or caesarean section (RR 1.18, 95% CI 0.74 to 1.89, one trial, 121 women).In the low- versus high-carbohydrate diet comparison, none of the 30 babies in a single trial were macrosomic; and no significant differences in caesarean section rates were seen (RR 1.40, 95% CI 0.57 to 3.43, one trial, 30 women).In the high-monounsaturated fat versus high-carbohydrate diet comparison, neither macrosomia or LGA (one trial 27 babies) (RR 0.65, 95% CI 0.91 to 2.18), (RR 0.54 95% CI 0.21 to 1.37), respectively showed significant differences. Women having a high-monounsaturated fat diet had a significantly higher body mass index (BMI) at birth (mean difference (MD) 3.90 kg/m², 95% CI 2.41 to 5.39, one trial, 27 women) and at six to nine months postpartum (MD 4.10 kg/m², 95% CI 2.34 to 5.86, one trial, 27 women) when compared with those having a high-carbohydrate diet. However, these findings were based on a single, small RCT with baseline imbalance in maternal BMI.Perinatal mortality was reported in only trial which recorded no fetal deaths in either the energy- restricted or unrestricted diet group.A single trial comparing ADA diet (20 grams gram fibre/day) with fibre-enriched fibre enriched diet (80 grams gram fibre/day) did not report any of our prespecified primary outcomes.Very limited data were reported on the prespecified outcomes for each of the six comparisons. Only one trial reported on early postnatal outcomes. No trial reported long-term health outcomes for women and their babies. No data were reported on health service cost or women's quality of life.

AUTHORS' CONCLUSIONS

Data for most comparisons were only available from single studies and they are too small for reliable conclusions about which types of dietary advice are the most suitable for women with GDM. Based on the current available evidence, we did not find any significant benefits of the diets investigated.Further larger trials with sufficient power to assess the effects of different diets for women with GDM on maternal and infant health outcomes are needed. Outcomes such as longer-term health outcomes for women and their babies, women's quality of life and health service cost should be included.

Physical activity of pregnant Hispanic women

BACKGROUND

A growing body of evidence suggests that physical activity during pregnancy can reduce risk of pregnancy complications. However, factors influencing activity in pregnant Hispanic women, who have high rates of sedentary activity as compared to non-Hispanic whites, are not well characterized.

PURPOSE

To assess patterns and correlates of physical activity among 1355 participants in Proyecto Buena Salud, a prospective cohort of pregnant Hispanic women in Massachusetts from 2006 to 2011.

METHODS

Analyses were conducted in 2012. Pre-, early-, mid-, and late-pregnancy physical activity were assessed using the Pregnancy Physical Activity Questionnaire. Women reported the frequency and duration of household/caregiving, occupational, sports/exercise, and transportation activities and were classified according to compliance with American College of Obstetricians and Gynecologists guidelines for physical activity.

RESULTS

Household/caregiving activity was the primary mode of pregnancy activity ranging from 56% to 60% of total activity while sports/exercise contributed the least (<10%). Compared to nulliparous women, women with two or more children were 85% less likely to become inactive at any time during pregnancy (OR=0.15, 95% CI=0.04, 0.56, p-trend <0.01). Women with one or more children increased their total physical activity on average 9.73±2.04 MET-hours/week and 12.04±2.39 MET-hours/week, respectively, with the onset of pregnancy (p<0.01). Those with the highest levels of total physical activity prior to pregnancy were 87% less likely to become inactive with the onset of pregnancy than those who were inactive prior to pregnancy (OR=0.13, 95% CI= 0.05, 0.29).

CONCLUSIONS

Findings can inform culturally appropriate interventions designed to reduce pregnancy complications through the promotion of physical activity during pregnancy.

Exercise for pregnant women for preventing gestational diabetes mellitus

BACKGROUND

Gestational diabetes mellitus (GDM) affects a significant number of women each year. GDM is associated with a wide range of adverse outcomes for women and their babies. Recent observational studies have found physical activity during normal pregnancy decreases insulin resistance and therefore might help to decrease the risk of developing GDM.

OBJECTIVES

To assess the effects of physical exercise for pregnant women for preventing glucose intolerance or GDM.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (2 April 2012), ClinicalTrials.gov (2 April 2012) and the WOMBAT Perinatal Trials Registry (2 April 2012).

SELECTION CRITERIA

Randomised and cluster-randomised trials assessing the effects of exercise for preventing pregnancy glucose intolerance or GDM.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility, extracted data and assessed the risk of bias of included studies.

MAIN RESULTS

We included five trials with a total of 1115 women and their babies (922 women and their babies contributed outcome data). Four of the five included trials had small sample sizes with one large trial that recruited 855 women and babies. All five included trials had a moderate risk of bias. When comparing women receiving additional exercise interventions with those having routine antenatal care, there was no significant difference in GDM incidence (three trials, 826 women, risk ratio (RR) 1.10, 95% confidence interval (CI) 0.66 to 1.84), caesarean section (two trials, 934 women, RR 1.33, 95% CI 0.97 to 1.84) or operative vaginal birth (two trials, 934 women, RR 0.83, 95% CI 0.58 to 1.17). No trial reported the infant primary outcomes prespecified in the review.None of the five included trials found significant differences in insulin sensitivity. Evidence from one single large trial suggested no significant difference in the incidence of developing pregnancy hyperglycaemia not meeting GDM diagnostic criteria, pre-eclampsia or admission to neonatal ward between the two study groups. Babies born to women receiving exercise interventions had a non-significant trend to a lower ponderal index (mean difference (MD) -0.08 gram x 100 m(3), 95% CI -0.18 to 0.02, one trial, 84 infants). No significant differences were seen between the two study groups for the outcomes of birthweight (two trials, 167 infants, MD -102.87 grams, 95% CI -235.34 to 29.60), macrosomia (two trials, 934 infants, RR 0.91, 95% CI 0.68 to 1.22), or small-for-gestational age (one trial, 84 infants, RR 1.05, 95% CI 0.25 to 4.40) or gestational age at birth (two trials, 167 infants, MD -0.04 weeks, 95% CI -0.37 to 0.29) or Apgar score less than seven at five minutes (two trials, 919 infants, RR 1.00, 95% CI 0.27 to 3.65). None of the trials reported long-term outcomes for women and their babies. No information was available on health services costs.

AUTHORS' CONCLUSIONS

There is limited randomised controlled trial evidence available on the effect of exercise during pregnancy for preventing pregnancy glucose intolerance or GDM. Results from three randomised trials with moderate risk of bias suggested no significant difference in GDM incidence between women receiving an additional exercise intervention and routine care.Based on the limited data currently available, conclusive evidence is not available to guide practice. Larger, well-designed randomised trials, with standardised behavioural interventions are needed to assess the effects of exercise on preventing GDM and other adverse pregnancy outcomes including large-for-gestational age and perinatal mortality. Longer-term health outcomes for both women and their babies and health service costs should be included. Several such trials are in progress. We identified another seven trials which are ongoing and we will consider these for inclusion in the next update of this review.

Physical activity during pregnancy and risk of hyperglycemia

OBJECTIVE

To determine the association between moderate and vigorous physical activities (MVPA) during midpregnancy and the risk of hyperglycemia.

METHODS

Data were from 1437 pregnant women. Frequency, duration, and intensity of MVPA during the previous 7 days were collected via questionnaire at 17-22 weeks' gestation. Modes of MVPA included work, recreation, transportation, caregiving, and indoor and outdoor household activities. Hyperglycemia was defined as a glucose concentration ≥130 mg/dL on a 1-hour, 50-g glucose challenge test or gestational diabetes mellitus (GDM) assessed at ~27 weeks' gestation. Multivariable Poisson regression estimated risks of hyperglycemia associated with total and mode-specific MVPA.

RESULTS

There were 269 women (18.7%) with hyperglycemia. Any metabolic equivalent (MET) hours/week of recreational MVPA was associated with a 27% lower risk of hyperglycemia (adjusted relative risk, [aRR] 0.73, 95% confidence interval [95%CI] 0.54-0.99). Multiplicative interaction terms were significant for prepregnancy body mass index (BMI) and recreational MVPA (p=0.01). Among women with prepregnancy BMI <25 kg/m(2), recreational MVPA was associated with a 48% lower risk of hyperglycemia (aRR 0.52, 95%CI 0.33-0.83) compared to women who reported none. There was no association of hyperglycemia and recreational MVPA among women with prepregnancy BMI <25 kg/m(2).

CONCLUSIONS

Recreational MVPA during pregnancy is associated with a lower risk of hyperglycemia, specifically among women with prepregnancy BMI <25 kg/m(2). Further research is warranted to determine recommended amounts and intensities of physical activity and to discern whether there are differences in the effects of physical activity between specific modes of physical activity or among subgroups of women in relation to hyperglycemia.

A prospective cohort study of modifiable risk factors for gestational diabetes among Hispanic women: design and baseline characteristics

OBJECTIVES

Women diagnosed with gestational diabetes mellitus (GDM) are at high risk for future diabetes, with rates of GDM consistently higher in Hispanic than non-Hispanic white women. Currently recognized risk factors for GDM are absent in up to half of affected women, and studies addressing modifiable risk factors for GDM in Hispanic women are sparse.

METHODS

Proyecto Buena Salud is an ongoing prospective cohort study of Hispanic women in Massachusetts designed to assess physical activity, psychosocial stress, and GDM risk. Bilingual interviewers recruit prenatal care patients early in pregnancy and assess activity, trait anxiety, perceived stress, and depressive symptoms using validated questionnaires.

RESULTS

Baseline characteristics of the first 632 participants are presented. Women were predominantly young (69% <24 years), were unmarried (87%), and had low levels of education (48% had less than high school). Women with high acculturation were less likely to live with a partner (OR: 0.6, 95% CI 0.4-0.8) than women with low acculturation. Few participants met physical activity guidelines during pregnancy (5.2%). Levels of perceived stress (mean 26.9 +/- 7.1), trait anxiety (mean 41.6 +/- 10.4), and depressive symptoms (33.2%) were high.

CONCLUSIONS

Proyecto Buena Salud represents a high-risk population of pregnant Hispanic women who are predominantly inactive, with higher levels of perceived stress, trait anxiety, and depressive symptoms compared to predominantly non-Hispanic white cohorts studied earlier. Therefore, Proyecto Buena Salud provides a unique opportunity to prospectively evaluate modifiable risk factors for GDM. Findings will inform prenatal behavioral intervention programs designed to address modifiable GDM risk factors.

Gestational Diabetes

Gestational diabetes mellitus (GDM) is one of the most common complications of pregnancy and is strongly related to subsequent risk of type 2 diabetes. The epidemics of obesity and diabetes and the increasing incidence of GDM in recent years highlight the importance of preventing GDM among women at high risk to avoid the associated short- and long-term adverse health outcomes for both mothers and their offspring. Indeed, women may be more likely to adopt healthy lifestyle habits during pregnancy and maintain these habits into the postpartum period. Although there is substantial evidence that targeting at-risk groups for type 2 diabetes prevention is effective if lifestyle changes are made, relatively little attention has been paid to the prevention of GDM. Therefore, the objective of this article is to review the scientific evidence regarding the association between modifiable risk factors and GDM; discuss how lifestyle interventions, including weight management through diet and exercise could be successful in reducing the risk for GDM; and provide recommendations for future lifestyle intervention programs with a focus on translation and dissemination of research findings.

Interventions for pregnant women with hyperglycaemia not meeting gestational diabetes and type 2 diabetes diagnostic criteria

BACKGROUND

Pregnancy hyperglycaemia without meeting gestational diabetes mellitus (GDM) diagnostic criteria affects a significant proportion of pregnant women each year. It is associated with a range of adverse pregnancy outcomes. Although intensive management for women with GDM has been proven beneficial for women and their babies, there is little known about the effects of treating women with hyperglycaemia who do not meet diagnostic criteria for GDM and type 2 diabetes (T2DM).

OBJECTIVES

To assess the effects of different types of management strategies for pregnant women with hyperglycaemia not meeting diagnostic criteria for GDM and T2DM (referred as borderline GDM in this review).

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 September 2011).

SELECTION CRITERIA

Randomised and cluster-randomised trials comparing alternative management strategies for women with borderline GDM.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility, extracted data and assessed risk of bias of included studies. Data were checked for accuracy.

MAIN RESULTS

We included four trials involving 543 women and their babies (but only data from 521 women and their babies is included in our analyses). Three of the four included studies had moderate to high risk of bias and one study was at low to moderate risk of bias. Babies born to women receiving management for borderline GDM (generally dietary counselling and metabolic monitoring) were less likely to be macrosomic (birthweight greater than 4000 g) (three trials, 438 infants, risk ratio (RR) 0.38, 95% confidence interval (CI) 0.19 to 0.74) or large-for-gestational (LGA) age (three trials, 438 infants, RR 0.37, 95% CI 0.20 to 0.66) when compared with those born to women in the routine care group. There were no significant differences in rates of caesarean section (three trials, 509 women, RR 0.93, 95% CI 0.68 to 1.27) and operative vaginal birth (one trial, 83 women, RR 1.37, 95% CI 0.20 to 9.27) between the two groups.

AUTHORS' CONCLUSIONS

This review found interventions including providing dietary advice and blood glucose level monitoring for women with pregnancy hyperglycaemia not meeting GDM and T2DM diagnostic criteria helped reduce the number of macrosomic and LGA babies without increasing caesarean section and operative vaginal birth rates. It is important to notice that the results of this review were based on four small randomised trials with moderate to high risk of bias without follow-up outcomes for both women and their babies.