Prenatal exercise is not associated with fetal mortality: a systematic review and meta-analysis

Abstract

ObjectiveTo perform a systematic review of the relationship between prenatal exercise and fetal or newborn death.DesignSystematic review with random-effects meta-analysis and meta-regression.Data sourcesOnline databases were searched up to 6 January 2017.Study eligibility criteriaStudies 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).ResultsForty-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/conclusionsAlthough 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.

Why can’t I exercise during pregnancy? Time to revisit medical ‘absolute’ and ‘relative’ contraindications: systematic review of evidence of harm and a call to action

“…Fear of miscarriage can be a barrier to prenatal exercise in early pregnancy 121 ; however, a recent meta-analysis demonstrated no increased odds of miscarriage or perinatal mortality in otherwise healthy pregnant women who exercised compared with those who did not. 18 It should be noted that this included spontaneous miscarriage data, and not specifically, recurrent pregnancy loss. Regardless, it remains unclear as to how exercise would negatively influence factors that lead to recurrent pregnancy loss.…”

“…17 Critically, these benefits occur without increasing the risk of having a small baby, preterm birth or a miscarriage. 18 Despite these known benefits of physical activity on maternal and fetal health, there remains a subset of women who are advised against exercise due to a variety of preexisting or pregnancy-specific conditions, known as contraindications.…”

Reproductive history, maternal anxiety and past physical activity practice predict physical activity levels throughout pregnancy

“…> 4000 g, 39% decreased odds) (Davenport et al, 2018b). The safety of prenatal PA has been confirmed as no increased odds of preterm birth, altered fetal growth (Davenport et al, 2018b), miscarriage (Davenport et al, 2019a) or cesarean section (Davenport et al, 2019b) have been reported. According to the 2019 Canadian Guideline for Physical Activity throughout Pregnancy, pregnant women without contraindications to PA should accumulate at least 150 min per week of moderate-intensity physical activity (MPA) (Mottola et al, 2018).…”

Atividade física para gestantes e mulheres no pós-parto: Guia de Atividade Física para a População Brasileira

“…As evidências disponíveis mostram que a prática de atividade física durante a gestação é segura e não apresenta riscos para o desenvolvimento fetal e saúde da criança (Quadro 3). Evidências de qualidade baixa apontam que a prática de atividade física durante a gestação não aumenta o risco de abortos, anomalias congênitas, mortalidade prematura 18 , ruptura da bolsa amniótica antes do início do trabalho de parto, cesariana, indução do trabalho de parto, tempo de parto, laceração do períneo, fadiga, lesão, trauma musculoesquelético e danos maternos, mesmo quando praticada no primeiro trimestre 19 . Também há evidências de qualidade baixa Quadro 2 -Resumo de evidências do efeito da atividade física sobre a saúde da mulher.…”