Objective To perform a systematic review of the relationship between prenatal exercise and fetal or newborn death.
Design Systematic review with random-effects meta-analysis and meta-regression.
Data sources Online databases were searched up to 6 January 2017.
Study eligibility criteria Studies of all designs were included (except case studies) if they were published in English, Spanish or French and contained information on the population (pregnant women without contraindication to exercise), intervention (subjective or objective measures of frequency, intensity, duration, volume or type of exercise, alone [“exercise-only”] or in combination with other intervention components [eg, dietary; “exercise + co-intervention”]), comparator (no exercise or different frequency, intensity, duration, volume and type of exercise) and outcome (miscarriage or perinatal mortality).
Results Forty-six studies (n=2 66 778) were included. There was ‘very low’ quality evidence suggesting no increased odds of miscarriage (23 studies, n=7125 women; OR 0.88, 95% CI 0.63 to 1.21, I2=0%) or perinatal mortality (13 studies, n=6837 women, OR 0.86, 95% CI 0.49 to 1.52, I2=0%) in pregnant women who exercised compared with those who did not. Stratification by subgroups did not affect odds of miscarriage or perinatal mortality. The meta-regressions identified no associations between volume, intensity or frequency of exercise and fetal or newborn death. As the majority of included studies examined the impact of moderate intensity exercise to a maximum duration of 60 min, we cannot comment on the effect of longer periods of exercise.
Summary/conclusions Although the evidence in this field is of ‘very low’ quality, it suggests that prenatal exercise is not associated with increased odds of miscarriage or perinatal mortality. In plain terms, this suggests that generally speaking exercise is ‘safe’ with respect to miscarriage and perinatal mortality.
- perinatal mortality
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Contributors MHD, MFM, KBA, GAD and S-MR contributed to the conception of the study. MHD, MFM, VJP, AJG, CEG, NB, LGS, KBA, GAD, RB and S-MR contributed to the design of the study and development of the search strategy. LGS conducted the systematic search. AK, RS, VLM, LR, FS, MJ, TN and A-AM completed the acquisition of data. MHD, NB and MN performed the data analysis. MHD and AK were the principal writers of the manuscript. All authors assisted with the interpretation; contributed to the drafting and revision of the final article and approved the final submitted version of the manuscript.
Funding This project was funded by a Canadian Institute of Health Research Knowledge Synthesis Grant. MHD is funded by an Advancing Women’s Heart Health Initiative New Investigator Award supported by Health Canada and the Heart and Stroke Foundation of Canada. RS is funded by a Canadian Institutes for Health Research Doctoral Research Award. AAM is funded by a Fonds de Recherche en Santé du Québec Doctoral Research Award.
Competing interests None declared.
Patient consent Not required.
Provenance and peer review Not commissioned; externally peer reviewed.