Types of participants
Participants of interest are pregnant or post-partum adult females (18 years and over), from all pre-pregnancy BMI categories. Women will be included if they have co-morbidities of gestational diabetes or diabetes; all other medical conditions will be excluded.
Types of interventions
Studies will be included if the weight management interventions include a dietary component and have an objective of determining the relationship with antenatal and/or postpartum weight change. The interventions must have been conducted across the antenatal or postpartum period, with intervention initiation at any point up to six weeks after delivery. Interventions will be compared with usual care, wait-list controls or alternative intervention component or intensity.
Types of outcomes
This review will consider studies that include body weight as the primary outcome, measured either during pregnancy and/or postpartum. Weight change outcomes reported as weight (kg or lb), Body Mass Index, waist or hip circumference and/or percentage body fat will be included. Adverse outcomes will be documented if reported.
Types of studies
This review will include only the quantitative study design of randomized controlled trials (RCTs) - level II evidence from National Health and Medical Research Council, and level 1 from The Joanna Briggs Institute.26
The search strategy is designed to find published studies in the English language from 1980 to present (September, 2014). The search did not aim to find earlier studies as the authors wanted to focus on literature published since the marked increase in obesity in the 1980s.27 A three-step search strategy will be utilized in this review. The initial limited search of MEDLINE and CINAHL will be undertaken, followed by analysis of the text words contained in the title and abstract, and of the index terms used to describe articles. A second search using all identified keywords and index terms will then be undertaken across all included databases. The databases to be searched include MEDLINE, EMBASE, CINAHL, Cochrane database, Scopus and PsycINFO. The third stage will involve hand searching reference lists of all identified reports and articles will be searched for additional studies. Only studies with published results in the literature will be considered.
Key words will include pregnan* or pregnancy or postpartum period or antenatal or postpartum or perinatal or postpartum or gestation AND obesity or body weight or overweight or weight status or weight or weight retention or body mass index or weight gain or weight loss or weight change or weight management or obes* AND diet* or nutrition* or eat*.
All studies identified during the database search will be retrieved and examined to ensure relevance and that they meet the inclusion criteria using the title, abstract and full description by two independent reviewers. If the two independent reviewers disagree on whether a study should be included, a third independent reviewer will be consulted until a consensus has been reached.
- Studies not published in the English language
- Studies in animals
Assessment of methodological quality
Quantitative papers selected for retrieval will be assessed by two independent reviewers for methodological quality before inclusion in the review, using standardized critical appraisal instruments from the Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument (JBI-MAStARI, Appendix I). Any disagreements that arise between the reviewers will be resolved through discussion, or with a third reviewer.
Data extraction from the studies included in the review will be conducted using the standardized data extraction tool from JBI-MAStARI (Appendix II). Data collected will include relevant information on study characteristics (e.g. intervention design, participants) and results from diet and/ or nutrition assessment and weight change:
- Study characteristics: detailed description of the dietary components of the intervention (e.g. dietary prescription method, self-monitoring strategies, individual or group counselling, weight gain recommendations), length of intervention, length of follow-up, data collection points, setting, participants (n, age, gender, retention), description of components in addition to diet intervention (e.g. inclusion of exercise goals or counselling, use of goal setting, breastfeeding support).
- Results: outcomes of significance to the review question; dietary assessment, pregnancy and post-natal weight change and whether objectively measured at each time point.
Data will be synthesized from experimental study designs as follows:
Experimental (e.g. RCT): Quantitative papers will, where possible, be pooled in statistical meta-analysis using JBI-MAStARI. Sub-group analysis will be performed where appropriate. All results will be subject to double data entry. Effect sizes expressed as odds ratio (for categorical data) and weighted mean differences (for continuous data) and their 95% confidence intervals will be calculated for analysis modify text as appropriate. Heterogeneity will be assessed statistically using the standard Chi-square. Where statistical pooling is not possible the findings will be presented in narrative form including tables and figures to aid in data presentation where appropriate.
Conflicts of interest
None to be declared.
This systematic literature review will form part of the theses work for PhD candidate Lisa Spencer from the University of Newcastle, Australia.
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Appendix I: Appraisal instruments
MAStARI appraisal instrument
Appendix II: Data extraction instruments
MAStARI data extraction instrument