title: Study protocol: differential effects of diet and physical activity based interventions in pregnancy on maternal and fetal outcomes--individual patient data (IPD) meta-analysis and health economic evaluation.
abstract: BACKGROUND
  Pregnant women who gain excess weight are at risk of complications during pregnancy and in the long term. Interventions based on diet and physical activity minimise gestational weight gain with varied effect on clinical outcomes. The effect of interventions on varied groups of women based on body mass index, age, ethnicity, socioeconomic status, parity, and underlying medical conditions is not clear. Our individual patient data (IPD) meta-analysis of randomised trials will assess the differential effect of diet- and physical activity-based interventions on maternal weight gain and pregnancy outcomes in clinically relevant subgroups of women.
  
  
  METHODS
  Randomised trials on diet and physical activity in pregnancy will be identified by searching the following databases: MEDLINE, EMBASE, BIOSIS, LILACS, Pascal, Science Citation Index, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Database of Abstracts of Reviews of Effects, and Health Technology Assessment Database. Primary researchers of the identified trials are invited to join the International Weight Management in Pregnancy Collaborative Network and share their individual patient data. We will reanalyse each study separately and confirm the findings with the original authors. Then, for each intervention type and outcome, we will perform as appropriate either a one-step or a two-step IPD meta-analysis to obtain summary estimates of effects and 95% confidence intervals, for all women combined and for each subgroup of interest. The primary outcomes are gestational weight gain and composite adverse maternal and fetal outcomes. The difference in effects between subgroups will be estimated and between-study heterogeneity suitably quantified and explored. The potential for publication bias and availability bias in the IPD obtained will be investigated. We will conduct a model-based economic evaluation to assess the cost effectiveness of the interventions to manage weight gain in pregnancy and undertake a value of information analysis to inform future research.
  
  
  BACKGROUND
  PROSPERO 2013: CRD42013003804.
authors.forename: Anneloes E
authors.initials: AE
authors.lastname: Ruifrok
authors.forename: Ewelina
authors.initials: E
authors.lastname: Rogozinska
authors.forename: Mireille N M
authors.initials: MN
authors.lastname: van Poppel
authors.forename: Girish
authors.initials: G
authors.lastname: Rayanagoudar
authors.forename: Sally
authors.initials: S
authors.lastname: Kerry
authors.forename: Christianne J M
authors.initials: CJ
authors.lastname: de Groot
authors.forename: SeonAe
authors.initials: S
authors.lastname: Yeo
authors.forename: Emma
authors.initials: E
authors.lastname: Molyneaux
authors.forename: Fionnuala M
authors.initials: FM
authors.lastname: McAuliffe
authors.forename: Lucilla
authors.initials: L
authors.lastname: Poston
authors.forename: Tracy
authors.initials: T
authors.lastname: Roberts
authors.affiliation: School of Health and Population Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK. r.d.riley@bham.ac.uk.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Riley
authors.forename: Arri
authors.initials: A
authors.lastname: Coomarasamy
authors.forename: Khalid
authors.initials: K
authors.lastname: Khan
authors.forename: Ben Willem
authors.initials: BW
authors.lastname: Mol
authors.forename: Shakila
authors.initials: S
authors.lastname: Thangaratinam
mesh_terms: D004038:Diet, Reducing; D004470:Economics, Medical; D005260:Female; D006801:Humans; D009043:Motor Activity; D011247:Pregnancy; D011256:Pregnancy Outcome; D000078202:Systematic Reviews as Topic; D015430:Weight Gain / Q000502:physiology*; D015201:Meta-Analysis as Topic