Effects of antenatal diet and physical activity on maternal and fetal outcomes: individual patient data meta-analysis and health economic evaluation
Authors: Rogozińska Ewelina , Marlin Nadine , Jackson Louise , Rayanagoudar Girish , Ruifrok Anneloes E , Dodds Julie , Molyneaux Emma , van Poppel Mireille NM , Poston Lucilla , Vinter Christina A , McAuliffe Fionnuala , Dodd Jodie M , Owens Julie , Barakat Ruben , Perales Maria , Cecatti Jose G , Surita Fernanda , Yeo SeonAe , Bogaerts Annick , Devlieger Roland , Teede Helena , Harrison Cheryce , Haakstad Lene , Shen Garry X , Shub Alexis , Beltagy Nermeen El , Motahari Narges , Khoury Janette , Tonstad Serena , Luoto Riitta , Kinnunen Tarja I , Guelfi Kym , Facchinetti Fabio , Petrella Elisabetta , Phelan Suzanne , Scudeller Tânia T , Rauh Kathrin , Hauner Hans , Renault Kristina , de Groot Christianne JM , Sagedal Linda R , Vistad Ingvild , Stafne Signe Nilssen , Mørkved Siv , Salvesen Kjell Å , Jensen Dorte M , Vitolo Márcia , Astrup Arne , Geiker Nina RW , Kerry Sally , Barton Pelham , Roberts Tracy , Riley Richard D , Coomarasamy Arri , Mol Ben Willem , Khan Khalid S , Thangaratinam Shakila 
Published: August 2017

BackgroundDiet- and physical activity-based interventions in pregnancy have the potential to alter maternal and child outcomes.ObjectivesTo 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 sourcesMEDLINE, 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 methodsResearchers 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.ResultsDiet 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).LimitationsThe 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.ConclusionDiet 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 workThe differential effects of lifestyle interventions on individual pregnancy outcomes need evaluation.Study registrationThis study is registered as PROSPERO CRD42013003804.FundingThe National Institute for Health Research Health Technology Assessment programme.