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Headline
Diet and activity interventions in pregnancy reduce gestational weight gain, with no significant benefit for a composite of maternal and fetal outcomes, irrespective of maternal characteristics, and are not cost-effective
Abstract
Background:
Diet- and physical activity-based interventions in pregnancy have the potential to alter maternal and child outcomes.
Objectives:
To assess whether or not the effects of diet and lifestyle interventions vary in subgroups of women, based on maternal body mass index (BMI), age, parity, Caucasian ethnicity and underlying medical condition(s), by undertaking an individual patient data (IPD) meta-analysis. We also evaluated the association of gestational weight gain (GWG) with adverse pregnancy outcomes and assessed the cost-effectiveness of the interventions.
Data sources:
MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Database of Abstracts of Reviews of Effects and Health Technology Assessment database were searched from October 2013 to March 2015 (to update a previous search).
Review methods:
Researchers from the International Weight Management in Pregnancy Collaborative Network shared the primary data. For each intervention type and outcome, we performed a two-step IPD random-effects meta-analysis, for all women (except underweight) combined and for each subgroup of interest, to obtain summary estimates of effects and 95% confidence intervals (CIs), and synthesised the differences in effects between subgroups. In the first stage, we fitted a linear regression adjusted for baseline (for continuous outcomes) or a logistic regression model (for binary outcomes) in each study separately; estimates were combined across studies using random-effects meta-analysis models. We quantified the relationship between weight gain and complications, and undertook a decision-analytic model-based economic evaluation to assess the cost-effectiveness of the interventions.
Results:
Diet and lifestyle interventions reduced GWG by an average of 0.70 kg (95% CI –0.92 to –0.48 kg; 33 studies, 9320 women). The effects on composite maternal outcome [summary odds ratio (OR) 0.90, 95% CI 0.79 to 1.03; 24 studies, 8852 women] and composite fetal/neonatal outcome (summary OR 0.94, 95% CI 0.83 to 1.08; 18 studies, 7981 women) were not significant. The effect did not vary with baseline BMI, age, ethnicity, parity or underlying medical conditions for GWG, and composite maternal and fetal outcomes. Lifestyle interventions reduce Caesarean sections (OR 0.91, 95% CI 0.83 to 0.99), but not other individual maternal outcomes such as gestational diabetes mellitus (OR 0.89, 95% CI 0.72 to 1.10), pre-eclampsia or pregnancy-induced hypertension (OR 0.95, 95% CI 0.78 to 1.16) and preterm birth (OR 0.94, 95% CI 0.78 to 1.13). There was no significant effect on fetal outcomes. The interventions were not cost-effective. GWG, including adherence to the Institute of Medicine-recommended targets, was not associated with a reduction in complications. Predictors of GWG were maternal age (summary estimate –0.10 kg, 95% CI –0.14 to –0.06 kg) and multiparity (summary estimate –0.73 kg, 95% CI –1.24 to –0.23 kg).
Limitations:
The findings were limited by the lack of standardisation in the components of intervention, residual heterogeneity in effects across studies for most analyses and the unavailability of IPD in some studies.
Conclusion:
Diet and lifestyle interventions in pregnancy are clinically effective in reducing GWG irrespective of risk factors, with no effects on composite maternal and fetal outcomes.
Future work:
The differential effects of lifestyle interventions on individual pregnancy outcomes need evaluation.
Study registration:
This study is registered as PROSPERO CRD42013003804.
Funding:
The National Institute for Health Research Health Technology Assessment programme.
Contents
- Plain English summary
- Scientific summary
- Chapter 1. Background
- Chapter 2. Objectives
- Chapter 3. Methods
- Chapter 4. Characteristics and quality of studies included in the individual participant data meta-analysis
- Study selection and individual participant data acquisition
- Characteristics of the studies included in the individual participant data analysis
- Characteristics of the individual participants in the individual participant data meta-analysis
- Risk of bias within eligible studies
- Quality assessment of studies that contributed data to individual participant data meta-analysis
- Chapter 5. Effect of diet- and physical activity-based interventions in pregnancy on maternal and fetal outcomes
- Chapter 6. Association of maternal weight and weight gain in pregnancy and pregnancy complications
- Chapter 7. Predictors of gestational weight gain
- Chapter 8. Economic evaluation and decision-analytic modelling
- Chapter 9. Discussion
- Acknowledgements
- References
- Appendix 1. Outcomes prioritised in Delphi survey
- Appendix 2. Search strategies
- Appendix 3. International Weight Management in Pregnancy individual participant data meta-analysis project variables
- Appendix 4. Variables recoding
- Appendix 5. Details of trials with unavailable individual participant data
- Appendix 6. Clinical characteristics of the randomised controlled trials
- Appendix 7. Risk-of-bias assessment
- Appendix 8. Sensitivity analysis for the main outcomes
- Appendix 9. Results of aggregate meta-analyses
- Appendix 10. Search strategies for systematic reviews undertaken to inform economic modelling
- Appendix 11. Probabilistic sensitivity analysis additional results
- List of abbreviations
About the Series
Article history
The research reported in this issue of the journal was funded by the HTA programme as project number 12/01/50. The contractual start date was in February 2013. The draft report began editorial review in November 2015 and was accepted for publication in August 2016. The authors have been wholly responsible for all data collection, analysis and interpretation, and for writing up their work. The HTA editors and publisher have tried to ensure the accuracy of the authors’ report and would like to thank the reviewers for their constructive comments on the draft document. However, they do not accept liability for damages or losses arising from material published in this report.
Declared competing interests of authors
Hans Hauner reports grants from the German Ministry of Education and Research, the Bavarian Ministry of Agriculture and Nutrition, the Bavarian Ministry of Health, the Helmholtz Center Munich, the Else Kröner-Fresenius Foundation, AOK Bavaria (health insurance fund), Amway and the German Research Foundation outside the submitted work. Ben Willem Mol reports other grants from ObsEva during the conduct of the study.
Last reviewed: November 2015; Accepted: August 2016.
- NLM CatalogRelated NLM Catalog Entries
- Effects of antenatal diet and physical activity on maternal and fetal outcomes: ...Effects of antenatal diet and physical activity on maternal and fetal outcomes: individual patient data meta-analysis and health economic evaluation
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