A Randomised Trial to Optimise Gestational Weight Gain and Improve Maternal and Infant Health Outcomes through Antenatal Dietary, Lifestyle and Exercise Advice: The OPTIMISE Randomised Trial

Fetal Growth and Adiposity of Infants Born Large for Gestational Age in Three Harmonized Randomized Trials

OBJECTIVE

 Infants born large for gestational age (LGA) are at an increased risk of short- and longer-term adverse outcomes. Understanding fetal growth and adiposity and their trajectories may help inform interventions to prevent birth of LGA infants. We aimed to compare fetal growth and adiposity measures of infants born LGA with those born not LGA, to determine whether the discrepancy at birth was primarily due to larger size throughout gestation, or instead to different trajectories of fetal growth.

STUDY DESIGN

 This was a secondary analysis of secondary outcomes of fetal growth and adiposity from three harmonized randomized trials-the LIMIT, GRoW, and Optimise randomized trials. These trials recruited women in early pregnancy, and a singleton gestation, from three major public metropolitan Adelaide maternity hospitals. Maternal body mass index (BMI) ranged from 18.5 to ≥40.0 kg/m2. Data were obtained from enrolled women who underwent research ultrasounds at 28 and 36 weeks' gestation. Outcome measures were ultrasound measures of fetal biometry and adiposity.

RESULTS

 Infants born LGA had larger fetal biometry measures, and higher growth trajectories, from 20 weeks' gestation. Fetal adiposity measures were consistently larger among infants born LGA and these differences increased over time. We did not find evidence that the differences in biometry and adiposity measurements varied according to maternal BMI.

CONCLUSION

 Infants born LGA had larger fetal biometry measures at all time points from 20 weeks' gestation, compared with infants born not LGA suggesting any interventions to prevent LGA likely need to commence earlier in pregnancy or prior to conception.

KEY POINTS

· Infants born LGA had larger fetal biometry measures from 20 weeks' gestation.. · Infants born LGA had larger fetal adiposity measures.. · Interventions to prevent LGA need to start earlier in pregnancy or prior to conception..

Does Dietitian Involvement During Pregnancy Improve Birth Outcomes? A Systematic Review

Maternal diet during pregnancy can have a significant impact on maternal and offspring health. As nutrition counselling is an important component of prenatal care, registered dietitians (RDs) are uniquely trained professionals who can provide personalized nutrition counselling customized to an individual's sociocultural needs. The objective of this systematic review was to determine if RD involvement during pregnancy is associated with a lower prevalence of adverse birth outcomes in the United States and Canada. The review was conducted through a search of four databases: PubMed, CINAHL, Embase, and Web of Science. A total of 14 studies were identified. Women had a lower prevalence of low birth weight and preterm infants when RDs were involved during prenatal care. While RD involvement during pregnancy was not associated with macrosomia, more research is needed to assess its relationship with small for gestational age, large for gestational age, and infant mortality. Future research should also investigate the specific dietary advice provided by RDs and the extent and timing of their involvement throughout pregnancy to better understand the mechanisms surrounding nutrition counselling, in utero development, and health outcomes.

The interaction effect of pre-pregnancy body mass index and maternal age on the risk of pregnancy complications in twin pregnancies after assisted reproductive technology

OBJECTIVE

The widespread use of assisted reproductive technology (ART) has led to an increased twin pregnancy rate and increased risk of pregnancy complications. Pre-pregnancy body mass index (BMI) and maternal age are both risk factors for pregnancy complications. This study aimed to explore whether there is an interaction effect between pre-pregnancy BMI and maternal age on pregnancy complications in women with twin pregnancies after ART.

METHODS

Data of 445,750 women with twin pregnancies after ART were extracted from the National Vital Statistics System (NVSS) database in 2016-2021 in this retrospective cohort study. Univariate and multivariate logistic regression analyses were used to explore (1) the associations between pre-pregnancy BMI, maternal age, and total pregnancy complications; (2) interaction effect between pre-pregnancy BMI and maternal age on total pregnancy complications; and (3) this interaction effect in parity, race, gestational weight gain (GWG), and preterm birth subgroups. The evaluation indexes were odds ratios (ORs), relative excess risk of interaction (RERI), attributable proportions of interaction (AP), and synergy index (S) with 95% confidence intervals (CIs).

RESULTS

A total of 6,827 women had pregnancy complications. After adjusting for the covariates, compared with women had non-AMA and pre-pregnancy BMI <25 kg/m2, higher maternal age combined with higher pre-pregnancy BMI was associated with higher odds of total pregnancy complications [OR = 2.16, 95%CI: (1.98-2.36)]. The RERI (95% CI) was 0.22 (0.04-0.41), AP (95% CI) was 0.10 (0.02-0.19), and S (95% CI) was 1.24 (1.03-1.49). Subgroup analysis results indicated that the potential additive effect between pre-pregnancy BMI and maternal age on total pregnancy complications was also found in women with different race, multipara/unipara, GWG levels, or preterm births/non-preterm births (all p < 0.05).

CONCLUSION

Pre-pregnancy BMI and maternal age may have an additive effect on the odds of pregnancy-related complications in women with twin pregnancy after ART.

Handling misclassified stratification variables in the analysis of randomised trials with continuous outcomes

Many trials use stratified randomisation, where participants are randomised within strata defined by one or more baseline covariates. While it is important to adjust for stratification variables in the analysis, the appropriate method of adjustment is unclear when stratification variables are affected by misclassification and hence some participants are randomised in the incorrect stratum. We conducted a simulation study to compare methods of adjusting for stratification variables affected by misclassification in the analysis of continuous outcomes when all or only some stratification errors are discovered, and when the treatment effect or treatment-by-covariate interaction effect is of interest. The data were analysed using linear regression with no adjustment, adjustment for the strata used to perform the randomisation (randomisation strata), adjustment for the strata if all errors are corrected (true strata), and adjustment for the strata after some errors are discovered and corrected (updated strata). The unadjusted model performed poorly in all settings. Adjusting for the true strata was optimal, while the relative performance of adjusting for the randomisation strata or the updated strata varied depending on the setting. As the true strata are unlikely to be known with certainty in practice, we recommend using the updated strata for adjustment and performing subgroup analyses, provided the discovery of errors is unlikely to depend on treatment group, as expected in blinded trials. Greater transparency is needed in the reporting of stratification errors and how they were addressed in the analysis.

Mental Health during the Interpregnancy Period and the Association with Pre-Pregnancy Body Mass Index and Body Composition: Data from the INTER-ACT Randomized Controlled Trial

Mental health problems and obesity are two common complications during pregnancy and postpartum. The preconception period is considered an appropriate period for prevention. Therefore, insights into interpregnancy mental health and the impact on weight and body composition are of interest to developing effective weight management strategies. The primary aim of this study is to assess the difference in women's mental health during the interpregnancy period and the association with pre-pregnancy body mass index (BMI) and body composition. The secondary aim is to study whether this association is affected by socio-demographic factors, interpregnancy interval and sleep. The study is a secondary analysis of the INTER-ACT e-health-supported lifestyle trial. Women were eligible if they had a subsequent pregnancy and mental health measurements at 6 weeks after childbirth and at the start of the next pregnancy (n = 276). We used univariate analyses to assess differences in mental health and performed regression analysis to assess their association with pre-pregnancy BMI and body composition at the start of the next pregnancy. Our results show a statistically significant increase in anxiety and depressive symptoms between 6 weeks after childbirth and the start of the next pregnancy (sSTAI-6 ≥ 40: +13%, p =≤ 0.001; GMDS ≥ 13: +9%, p = 0.01). Of the women who were not anxious at 6 weeks after childbirth (sSTAI < 40), more than one-third (39%) developed anxiety at the start of the next pregnancy (p =≤ 0.001). Regression analysis showed that sense of coherence (SOC-13) at the start of the next pregnancy was independently associated with women's pre-pregnancy BMI and fat percentage. We believe that the development of preconception lifestyle interventions that focus on both weight reduction and support in understanding, managing and giving meaning to stressful events (sense of coherence) may be of added value in optimizing women's preconception health.

Is Maternal Carbohydrate Intake Having an Impact on Newborn Birth Weight? A Systematic Review

Glucose is a vital fuel for fetal growth, and carbohydrates are the primary source of glucose in the diet. The effects of carbohydrate intake during pregnancy on neonatal birth weight have not been fully investigated or systematically reviewed. Therefore, this systematic review aimed to collate the available evidence to determine whether carbohydrate intake during pregnancy impacts newborn birth weight. A literature search was performed from inception to March 2022 in Embase, Medline, and PsycInfo. Articles published in English were independently screened for the title and abstracts, and then for full texts. Out of 17 studies included, a significant relationship between the intake of maternal carbohydrate or its subcomponents and neonatal birth weight was reported in six studies. Of them, one study reported that higher carbohydrate intake in early pregnancy was associated with lower birth weight. The two other studies reported a positive correlation between maternal carbohydrate intake and neonatal birth weight regarding first- and second-trimester intake. Maternal carbohydrate intake may have an impact on birth weight, as suggested by the included studies in this systematic review. However, the overall review indicates contradictory findings concerning the relationship between carbohydrate intake and neonatal birth weight. Studies assessing the type of carbohydrate and the amount consumed with improved methodological quality are recommended.

Evidence of lifestyle interventions in a pregnant population with chronic hypertension and/or pre-existing diabetes: A systematic review and narrative synthesis

BACKGROUND

Pregnant people with chronic hypertension, pre-existing diabetes or both are at high risk of developing cardiovascular disease. Lifestyle interventions play an important role in disease management in non-pregnant populations.

AIM

To review the existing evidence of randomised controlled trials (RCTs) that examine lifestyle interventions in pregnant people with chronic hypertension and/or pre-existing diabetes.

METHODS

A systematic review and narrative synthesis was conducted. Five electronic databases were searched from inception to April 2021 for RCTs evaluating antenatal lifestyle interventions in people with chronic hypertension and/or pre-existing diabetes with outcomes to include weight or blood pressure change.

RESULTS

Nine randomised controlled trials including 7438 pregnant women were eligible. Eight studies were mixed pregnant populations that included women with chronic hypertension and/or pre-existing diabetes. One study included only pregnant women with pre-existing diabetes. Intervention characteristics and procedures varied and targeted diet, physical activity and/or gestational weight. All studies reported weight and one study reported blood pressure change. Outcome data were frequently unavailable for the subset of women of interest, including subgroup data on important pregnancy and birth complications. Eligibility criteria were often ambiguous and baseline data on chronic hypertension was often omitted.

CONCLUSION

A lack of primary interventional trials examining the effect of lifestyle interventions on weight and blood pressure outcomes in pregnant populations with chronic hypertension and/or pre-existing diabetes was evident. Lifestyle modification has the potential to alter disease progression. Future trials should address the ambiguity and frequent exclusion of these important populations.

Physical exercise interventions for perinatal depression symptoms in women: A systematic review and meta-analysis

Background

The previous meta-analysis indicated that physical exercise could play a crucially therapeutic role in reducing perinatal depression symptoms in women. However, the efficacy varies across different exercise types, forms, intensities, and duration.

Aim

The purpose of this study was to review and evaluate the effects of different types, forms, intensities, and duration of exercise for improving perinatal depressive symptoms.

Design

A systematic review and meta-analysis.

Methods

Randomized controlled trials until December 2021 were searched from seven databases, including PubMed, EMBASE, Medline, CINAHL, Web of Science, Cochrane Library, and PsycINFO. The risk of bias in eligible trials was evaluated using the Cochrane Risk of Bias tool. When high heterogeneity was tested, we used random-effects models. A funnel plot was used to assess the publication bias. This review was performed under the PRISMA guidelines, Consensus on Exercise Reporting (CERT) checklist and Cochrane Handbook. The certainty of the body of evidence was assessed using the GRADE method.

Results

Of 1,573 records, 20 trials were identified in this study. The results of this review revealed that women with perinatal depression symptoms gained benefits from physical exercise [OR = 0.62, 95% CI (0.45, 0.86), P = 0.004; MD = -0.57, 95% CI (-0.83, -0.30), P < 0.0001]. Type of walking [SMD = -1.06, 95% CI (-1.92, -0.19), P < 0.00001], form of "Individual + group-based"exercise [SMD = -0.91, 95% CI (-0.80, -0.03), P = 0.04], intensity of ≥150 min per week [SMD = -0.84, 95% CI (-1.53, -0.15), P = 0.02], and ≥12 weeks duration [SMD = -0.53, 95% CI (-0.75, -0.31), P < 0.00001] seemed to generate more prominent improvement on perinatal depression symptoms.

Conclusion

Physical exercise showed a significant effect on reducing perinatal depressive symptoms. This meta-analysis provides an important update on exercise's efficacy in treating perinatal depression. Further higher quality and large-scale trials are needed to substantiate our findings.

Systematic review registration

[https://www.crd.york.ac.uk/prospero/], identifier [CRD42022296230].

Exercise During Pregnancy

BACKGROUND

Pregnancy is a good time to motivate women to implement health-promoting behaviors in their everyday lives. There is no official German-language guideline for the counseling of pregnant women by professionals involved in their care. The goal of this review is, therefore, to discuss the links between exercise and gestational diabetes mellitus (GDM), low birth weight, and prematurity.

METHODS

This review is based on pertinent articles retrieved by a systematic search of PubMed and the Web of Science. The articles included in the evaluation were reports of randomized controlled trials (RCTs) and meta-analyses of RCTs of exercise interventions in pregnant women that were published from 1 January 2011 to 15 November 2021.

RESULTS

A structured exercise program during pregnancy can lower the risk of gestational diabetes by as much as 49%. A 25% risk reduction for GDM was achieved with 140 minutes of exercise per week. The mean birth weight was not affected but the rate of excessively heavy newborns was lowered by 32-59% in the normal-weight subgroup. This effect was not seen in the overweight subgroup, possibly because of poorer compliance. Exercise did not elevate the risk of preterm delivery.

CONCLUSION

Regular exercise during pregnancy lessens gestationally induced weight gain and lowers the risk of excessive weight gain, as well as the risk of GDM, without elevating the risk of preterm delivery.

Effectiveness of a nurse practitioner-led cardiovascular prevention clinic at reduction of metabolic syndrome following maternal complications of pregnancy: a preliminary analysis

AIM

Maternal complications of pregnancy, including hypertensive disorders of pregnancy, gestational diabetes mellitus, intrauterine growth restriction, preterm labour, and placental abruption, are associated with increased risk of future cardiometabolic disease. Lifestyle interventions that focus on preventative strategies for this young, high-risk population of women may assist in cardiometabolic disease risk reduction. The aim of this preliminary registry analysis was to observe the change in maternal metabolic syndrome status after receiving a nurse practitioner-led lifestyle intervention delivered soon after a complicated pregnancy.

METHOD

This preliminary analysis included 64 eligible women who had attended both baseline (approximately 6 months postpartum) and review (approximately eighteen months postpartum) appointments at the postpartum lifestyle clinic after an index pregnancy complicated by at least one maternal complication of pregnancy. Metabolic syndrome status at both appointments was assessed.

RESULTS

At the baseline appointment, 22 (34.4%) women met the criteria for metabolic syndrome. This number reduced at the review appointment to 19 (29.7%). This difference was not statistically significant. There were some modest improvements in the individual cardiometabolic risk factors, as well as marked improvements in the women who had recovered from metabolic syndrome over twelve months.

CONCLUSION

There was a high percentage of metabolic syndrome present early in the postpartum period. The results of this preliminary analysis highlight the importance of continuing preventative care and ongoing research for this group of high-risk women.

Physical activity during pregnancy: a systematic review for the assessment of current evidence with future recommendations

Background

Physical activity is essential to maternal and infant health. Healthcare professionals should inform pregnant women about benefits of physical activity to prevent possible health issues. Those recommendations should elaborate on relevant contemporary evidence. The aim of this study was to review evidence-based recommendations for physical activity during pregnancy.

Methods

A systematic search, analysis and synthesis of conducted randomised controlled trials (RCTs) was conducted from October 2021 to June 2022 in following databases: PubMed, CINAHL, ScienceDirect and Web of Science. Literature was searched using inclusion and exclusion criteria and following PRISMA recommendations.

Results

Benefits for pregnant-women health and well-being were reported while performing aerobic exercise, lumbar stabilization and stretching exercise, water exercise, nerve and tendon-slip exercise, resistance training and strength training. For all exercise modalities it is recommended to perform moderate intensity activities during the whole time of pregnancy.

Conclusions

This systematic literature review supplements current knowledge on physical activity of pregnant women. Exercise interventions are listed and suggested in an integrative model with physical-fitness components to contextualize and promote physical activity among pregnant women.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13102-022-00524-z.

Maternal overweight and obesity during pregnancy: strategies to improve outcomes for women, babies, and children

INTRODUCTION

Women with overweight and obesity, and their children, are at increased risk of adverse pregnancy, birth, and longer term health outcomes, believed to be compounded by excessive gestational weight gain (GWG). Research to date has focused on interventions to reduce excessive GWG through changes to maternal diet and/or lifestyle.

AREAS COVERED

Current clinical recommendations for GWG vary according to a woman's early pregnancy body mass index, based on assumptions that associations between GWG and adverse pregnancy outcomes are causal in nature, and modifiable. While there are small differences in GWG following pregnancy interventions, there is little evidence for clinically relevant effects on pregnancy, birth, and longer term childhood outcomes. This review considers interventional studies targeting women with overweight or obesity to reduce GWG in an effort to improve maternal and infant health, and the current evidence for interventions prior to conception.

EXPERT OPINION

GWG is not modifiable via diet and lifestyle change, and continued efforts to find the 'right' intervention for women with overweight and obesity during pregnancy are unjustified. Researchers should focus on gathering evidence for interventions prior to pregnancy to optimize maternal health and weight to improve pregnancy, birth, and longer term health outcomes associated with obesity.

Be Healthy in Pregnancy (BHIP): A Randomized Controlled Trial of Nutrition and Exercise Intervention from Early Pregnancy to Achieve Recommended Gestational Weight Gain

A randomized two-arm prospective superiority trial tested the efficacy of a novel structured and monitored nutrition (bi-weekly counselling for individualized energy and high dairy protein diet) and exercise program (walking goal of 10,000 steps/day) (intervention) compared to usual care (control) in pregnant women to achieve gestational weight gain (GWG) within current recommendations. Women recruited in communities in southern Ontario, Canada were randomized at 12–17 weeks gestation with stratification by site and pre-pregnancy BMI to intervention (n = 119) or control (n = 122). The primary outcome was the proportion of women who achieved GWG within the Institute of Medicine recommendations. Although the intervention compared to control group was more likely to achieve GWG within recommendations (OR = 1.51; 95% CI (0.81, 2.80)) and total GWG was lower by 1.45 kg (95% CI: (−11.9, 8.88)) neither reached statistical significance. The intervention group achieved significantly higher protein intake at 26–28 week (mean difference (MD); 15.0 g/day; 95% CI (8.1, 21.9)) and 36–38 week gestation (MD = 15.2 g/day; 95% CI (9.4, 21.1)) and higher healthy diet scores (22.5 ± 6.9 vs. 18.7 ± 8.5, p < 0.005) but step counts were similar averaging 6335 steps/day. Pregnancy and infant birth outcomes were similar between groups. While the structured and monitored nutrition with counselling improved diet quality and protein intake and may have benefited GWG, the exercise goal of 10,000 steps/day was unachievable. The results can inform future recommendations for diet and physical activity in pregnancy.

Gestational weight gain, appetite regulating hormones, and metformin treatment in polycystic ovary syndrome: A longitudinal, placebo-controlled study

OBJECTIVE

To explore mechanisms that modulate gestational weight gain (GWG) in women with polycystic ovary syndrome (PCOS) and healthy controls.

DESIGN

Sub-sample of randomised controlled trials (PCOS) combined with a prospective cohort (controls).

SETTING

Eleven Norwegian, Swedish, and Icelandic hospitals.

POPULATION

Pregnant women with PCOS treated with metformin (PCOS-M, n = 36) or placebo (PCOS-P, n = 37), and healthy pregnant women (HC, n = 15).

METHODS

Serum levels of the appetite regulating hormones leptin, ghrelin, allopregnanolone, and soluble leptin receptor (sOB-R) were determined in the first and third trimesters.

MAIN OUTCOME MEASURES

Excessive GWG (eGWG) relative to body mass index according to Institute of Medicine (IOM) guideline. Serum leptin/sOB-R ratio, or free-leptin-index (FLI), as biomarker of leptin sensitivity. Serum ghrelin and allopregnanolone levels.

RESULTS

The overall prevalence of eGWG was 44% (38/86). Women with eGWG had higher first and third trimester FLI (P < 0.001), and lower third trimester allopregnanolone levels (P = 0.003) versus women with non-eGWG. The prevalence of eGWG was lower in PCOS-M versus PCOS-P (28% versus 62%, odds ratio = 0.4, 95% CI 0.2-0.8, P = 0.005). FLI decreased during pregnancy in PCOS-M (P = 0.01), but remained unaltered in PCOS-P and HC. Ghrelin and allopregnanolone levels were comparable in PCOS-M, PCOS-P and HC throughout pregnancy.

CONCLUSION

Excessive GWG is associated with enhanced leptin resistance, and attenuated physiological increase in serum allopregnanolone levels during pregnancy. Metformin reduces the risk for eGWG and improves leptin sensitivity in pregnant women with PCOS.

Effects of the First 1000 Days Program, a systems-change intervention, on obesity risk factors during pregnancy

BACKGROUND

First 1000 Days is a systems-oriented program starting in early pregnancy lasting through the first 24 months of infancy focused on preventing obesity and related risk factors among low income, mother-infant pairs. The program was developed in partnership with stakeholders to create an infrastructure for system-wide change. It includes screening for adverse health behaviors and socio-contextual factors, patient navigation and educational materials to support behavior change and social needs, and individualized health coaching for women at highest risk of obesity and has been shown to reduce excess gestational weight gain for women who were overweight at the start of their pregnancy. The purpose of this study was to examine changes from the first to third trimester for women participating in the First 1000 Days Program.

METHODS

We collected information through self-administered questionnaires during the first and third trimester of gestation and from electronic health records relating to obesity risk factors. Measures collected included behavior (i.e., diet, physical activity and screen time) and psychosocial (i.e., anxiety) outcomes, as well as enrollment in Women, Infant, and Children (WIC) program. We examined the extent to which participation in the program was associated with changes in behaviors and psychosocial outcomes among women during pregnancy.

RESULTS

Women completed surveys at their initial and third trimester prenatal visits (n = 264). Mean age (SD) was 30.2 (5.51) years and 75% had an annual household income of <$50,000. Mean pre-pregnancy body mass index (BMI) was 27.7 kg/m2 and 64% started pregnancy with a BMI ≥ 25 kg/m2. In multivariable adjusted models, we observed decreases in intake of sugary-drinks (- 0.95 servings/day; 95% CI: - 1.86, - 0.03) and in screen time (- 0.21 h/day; 95% CI: - 0.40, - 0.01), and an increase in physical activity (0.88 days/week; 95% CI: 0.52, 1.23) from the first to third trimester. We also observed a decrease in pregnancy-related anxiety score (- 1.06 units; 95% CI: - 1.32, - 0.79) and higher odds of enrollment in Women, Infant, and Children (WIC) program (OR: 2.58; 95% CI: 1.96, 3.41).

CONCLUSIONS

Our findings suggest that a systems-oriented prenatal intervention may be associated with improvements in behaviors and psychosocial outcomes during pregnancy among low-income mothers.

TRIAL REGISTRATION

ClinicalTrials.gov ( NCT03191591 ; Retrospectively registered on June 19, 2017).

The role of midwives and obstetrical nurses in the promotion of healthy lifestyle during pregnancy

Women with maternal obesity, an unhealthy lifestyle before and during pregnancy and excess gestational weight gain have an increased risk of adverse pregnancy and birth outcomes that can also increase the risk of long-term poor health for them and their children. Pregnant women have frequent medical appointments and are highly receptive to health advice. Healthcare professionals who interact with women during pregnancy are in a privileged position to support women to make lasting healthy lifestyle changes that can improve gestational weight gain and pregnancy outcomes and halt the intergenerational nature of obesity. Midwives and obstetrical nurses are key healthcare professionals responsible for providing antenatal care in most countries. Therefore, it is crucial for them to build and enhance their ability to promote healthy lifestyles in pregnant women. Undergraduate midwifery curricula usually lack sufficient lifestyle content to provide emerging midwives and obstetrical nurses with the knowledge, skills, and confidence to effectively assess and support healthy lifestyle behaviours in pregnant women. Consequently, registered midwives and obstetrical nurses may not recognise their role in healthy lifestyle promotion specific to healthy eating and physical activity in practice. In addition, practising midwives and obstetrical nurses do not consistently have access to healthy lifestyle promotion training in the workplace. Therefore, many midwives and obstetrical nurses may not have the confidence and/or skills to support pregnant women to improve their lifestyles. This narrative review summarises the role of midwives and obstetrical nurses in the promotion of healthy lifestyles relating to healthy eating and physical activity and optimising weight in pregnancy, the barriers that they face to deliver optimal care and an overview of what we know works when supporting midwives and obstetrical nurses in their role to support women in achieving a healthy lifestyle.

Effects of Maternal Exercise During Pregnancy on Perinatal Growth and Childhood Obesity Outcomes: A Meta-analysis and Meta-regression

BACKGROUND

Perinatal growth abnormalities program susceptibility to childhood obesity, which is further exaggerated by maternal overweight and obesity (MO) during pregnancy. Exercise is highly accessible, but reports about the benefits of maternal exercise on fetal growth and childhood obesity outcomes are inconsistent, reducing the incentives for pregnant women to participate in exercise to improve children's perinatal growth.

OBJECTIVE

This systematic review and meta-analysis aims to establish evidence-based efficacy of exercise in mothers with normal weight (MNW) and MO during pregnancy in reducing the risks of perinatal growth abnormalities and childhood obesity. In addition, the impacts of exercise volume are also assessed.

METHODS

The PubMed, ScienceDirect, Web of Science, and Cochrane Library databases were searched from inception to February 15, 2020. We included randomized controlled trials with exercise-only intervention or exercise with other confounders in pregnant MNW (body mass index, BMI 18.5-24.9 kg/m²) and MO (BMI ≥ 25 kg/m²), which were further subgrouped in the meta-analysis. Primary outcomes included birth weight, preterm birth, small for gestational age (SGA), large for gestational age (LGA), infant and childhood weight, and childhood obesity. A linear meta-regression analysis was also used to explore the effects of exercise volume on outcomes.

RESULTS

99 studies were included in the meta-analysis (n = 596,876), and individual study quality ranged from fair to good according to the Newcastle-Ottawa scale assessment. Exercise only interventions in MNW reduced preterm birth by 15% (26 studies, n = 76,132; odds ratio [OR] 0.85; 95% CI 0.72, 1.01; I² = 83.3%), SGA by 17% (33 studies, n = 92,351; OR 0.83; 95% CI 0.71, 0.98; I² = 74.5%) and LGA by 17% (29 studies, n = 84,310; OR 0.83; 95% CI 0.74, 0.95; I² = 60.4%). Exercise only interventions in MO reduced preterm birth by 33% (2 studies, n = 3,050; OR 0.67; 95% CI 0.70, 0.96; I² = 0%), SGA by 27% (8 studies, n = 3,909; OR 0.73; 95% CI 0.50, 1.05; I² = 40.4%) and LGA by 55% (9 studies, n = 81,581; OR 0.45; 95% CI 0.18, 1.11; I² = 98.3%). Exercise only interventions in MNW reduced childhood obesity by 53% (3 studies, n = 6,920; OR 0.47; 95% CI 0.36, 0.63; I² = 77.0%). However, no significant effect was observed in outcomes from exercise confounders in either MNW or MO. In the meta-regression, the volume of exercise-only intervention in MNW was negatively associated with birth weight, greatly driven by volumes more than 810 metabolic equivalents (MET)-min per week. Other outcomes were not associated with exercise volume.

CONCLUSIONS

This systematic review and meta-analysis suggests that exercise during pregnancy in both MNW and MO safely and effectively reduce the risks of preterm birth, SGA, and LGA. Furthermore, MNW exercise also reduces the risk of childhood obesity. Overall, regardless of prepregnancy BMI, maternal exercise during pregnancy provides an excellent opportunity to mitigate the high prevalence of adverse birth outcomes and childhood obesity.

Lifestyle, Maternal Nutrition and Healthy Pregnancy

Healthy lifestyle habits spanning from preconception to postpartum are considered as a major safeguard for achieving successful pregnancies and for the prevention of gestational diseases. Among preconception priorities established by the World Health Organization (WHO) are healthy diet and nutrition, weight management, physical activity, planned pregnancy and physical, mental and psychosocial health. Most studies covering the topic of healthy pregnancies focus on maternal diet because obesity increases the risks for adverse perinatal outcomes, including gestational diabetes mellitus, large for gestational age newborns, or preeclampsia. Thus, foods rich in vegetables, essential and polyunsaturated fats and fibre-rich carbohydrates should be promoted especially in overweight, obese or diabetic women. An adequate intake of micronutrients (e.g. iron, calcium, folate, vitamin D and carotenoids) is also crucial to support pregnancy and breastfeeding. Moderate physical activity throughout pregnancy improves muscle tone and function, besides decreasing the risk of preeclampsia, gestational diabesity (i.e. diabetes associated with obesity) and postpartum overweight. Intervention studies claim that an average of 30 min of exercise/day contributes to long-term benefits for maternal overall health and wellbeing. Other factors such as microbiome modulation, behavioural strategies (e.g. smoking cessation, anxiety/stress reduction and sleep quality), maternal genetics and age, social class and education might also influence the maternal quality of life. These factors contribute to ensure a healthy pregnancy, or at least to reduce the risk of adverse maternal and foetal outcomes during pregnancy and later in life.

Counseling and Behavioral Interventions for Healthy Weight and Weight Gain in Pregnancy: Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

Counseling and active behavioral interventions to limit excess gestational weight gain (GWG) during pregnancy may improve health outcomes for women and infants. The 2009 National Academy of Medicine (NAM; formerly the Institute of Medicine) recommendations for healthy GWG vary according to prepregnancy weight category.

OBJECTIVE

To review and synthesize the evidence on benefits and harms of behavioral interventions to promote healthy weight gain during pregnancy to inform the US Preventive Services Task Force recommendation.

DATA SOURCES

Ovid MEDLINE and the Cochrane Library to March 2020, with surveillance through February 2021.

STUDY SELECTION

Randomized clinical trials and nonrandomized controlled intervention studies focused on diet, exercise, and/or behavioral counseling interventions on GWG.

DATA EXTRACTION AND SYNTHESIS

Independent data abstraction and study quality rating with dual review.

MAIN OUTCOMES AND MEASURES

Gestational weight-related outcomes; maternal and infant morbidity and mortality; harms.

RESULTS

Sixty-eight studies (N = 25 789) were included. Sixty-seven studies evaluated interventions during pregnancy, and 1 evaluated an intervention prior to pregnancy. GWG interventions were associated with reductions in risk of gestational diabetes (43 trials, n = 19 752; relative risk [RR], 0.87 [95% CI, 0.79 to 0.95]; absolute risk difference [ARD], -1.6%) and emergency cesarean delivery (14 trials, n = 7520; RR, 0.85 [95% CI, 0.74 to 0.96]; ARD, -2.4%). There was no significant association between GWG interventions and risk of gestational hypertension, cesarean delivery, or preeclampsia. GWG interventions were associated with decreased risk of macrosomia (25 trials, n = 13 990; RR, 0.77 [95% CI, 0.65 to 0.92]; ARD, -1.9%) and large for gestational age (26 trials, n = 13 000; RR, 0.89 [95% CI, 0.80 to 0.99]; ARD, -1.3%) but were not associated with preterm birth. Intervention participants experienced reduced weight gain across all prepregnancy weight categories (55 trials, n = 20 090; pooled mean difference, -1.02 kg [95% CI, -1.30 to -0.75]) and demonstrated lower likelihood of GWG in excess of NAM recommendations (39 trials, n = 14 271; RR, 0.83 [95% CI, 0.77 to 0.89]; ARD, -7.6%). GWG interventions were associated with reduced postpartum weight retention at 12 months (10 trials, n = 3957; mean difference, -0.63 kg [95% CI, -1.44 to -0.01]). Data on harms were limited.

CONCLUSIONS AND RELEVANCE

Counseling and active behavioral interventions to limit GWG were associated with decreased risk of gestational diabetes, emergency cesarean delivery, macrosomia, and large for gestational age. GWG interventions were also associated with modest reductions in mean GWG and decreased likelihood of exceeding NAM recommendations for GWG.

Gestational Weight Gain-Re-Examining the Current Paradigm

Our aim was to investigate the underlying assumptions of the current gestational weight gain (GWG) paradigm, specifically that—(1) GWG is modifiable through diet and physical activity; (2) optimal GWG and risk of excess GWG, vary by pre-pregnancy body mass index (BMI) category and (3) the association between GWG and adverse pregnancy outcomes is causal. Using data from three large, harmonized randomized controlled trials (RCTs) of interventions to limit GWG and improve pregnancy outcomes and with appropriate regression models, we investigated the link between diet and physical activity and GWG; the relationships between pre-pregnancy BMI, GWG and birth weight z-score; and the evidence for a causal relationship between GWG and pregnancy outcomes. We found little evidence that diet and physical activity in pregnancy affected GWG and that the observed relationships between GWG and adverse pregnancy outcomes are causal in nature. Further, while there is evidence that optimal GWG may be lower for women with higher BMI, target ranges defined by BMI categories do not accurately reflect risk of adverse outcomes. Our findings cast doubt upon current advice regarding GWG, particularly for overweight and obese women and suggest that a change in focus is warranted.