Abstract
BACKGROUND: Guidelines recommending regular physical activity in pregnancy for improving pregnancy outcomes are informed by published meta-analyses. Inclusion of randomised trials of poor methodological quality may bias effect estimates. OBJECTIVES: To assess the validity of these recommendations by focusing on trial quality. SEARCH STRATEGY: Systematic search of PubMed, PubMed Central, Ovid Medline, Embase, Cochrane Central Register of Controlled Trials, and CINAHL from inception to 14 December 2023. SELECTION CRITERIA: Randomised trials evaluating an antenatal physical activity intervention alone, compared with no such intervention. DATA COLLECTION AND ANALYSIS: Trial quality was assessed using the Cochrane Risk of Bias tool. Independent of this, studies were grouped based on degree of deviation from the intention to treat principle. Sequential meta-analysis was performed in which greater degrees of potential bias were allowed. Between intervention group comparisons used, relative risks or mean differences with 95% confidence intervals for dichotomous outcomes and continuous outcomes, respectively. MAIN RESULTS: Overall, the quality of trial reporting was low. Only 5 trials (12.5%) were performed and analysed in keeping with the intention to treat principle. When considering only those trials performed rigorously, there was no evidence that antenatal physical activity improves pregnancy outcomes or limits gestational weight gain (WMD -0.60 kg; 95% CI -2.17, 0.98 WMD -0.60 kg; 95% CI -2.17, 0.98). CONCLUSIONS: When considering only trials at no/negligible risk of bias, antenatal physical activity interventions were not associated with improved pregnancy outcomes. Most trials were not methodologically rigorous. Incorporation of such meta-analyses into pregnancy care guidelines may result in inaccurate recommendations.