Natural childbirth is a normal physiological approach of human reproduction, while in China, the cesarean section rate has exceeded the upper limit recommended by the WHO by more than two times. As a nonpharmaceutical intervention facilitating natural childbirth, physical exercise should be valued by relevant departments.

To perform a meta-analysis of studies regarding effects of physical exercise interventions on promoting natural childbirth probability, and to attempt to recommend a better exercise scheme.

Randomized controlled trials (RCTs) about the effect of intrapregancy physical exercise versus routine care (health duration or irregular physical exercise) improving the probability of natural childbirth published between 1990 and 2021 were searched in databases of CNKI, SinoMed, CQVIP, PubMed, EMBase, Web of Science, and Cochrane Library. Meanwhile, the references of systematic reviews on relevant RCTs were also searched and reviewed. Data extraction and methodological quality assessment were conducted for the included studies. RevMan 5.2 was used for meta-analysis. GRADE was used to rate the quality of evidence concerning an outcome.

A total of 30 studies with 3 910 subjects were included. Meta-analysis found that physical exercise interventions were superior to routine care in improving the natural childbirth rate〔RR=1.34, 95%CI (1.28, 1.40) , P<0.000 01〕. Subgroup analyses revealed that natural childbirth rate was improved the most by physical exercise intervention started later than 24 weeks of gestation, followed by that started at 13-24 weeks of gestation, and 12 or less than 12 weeks of gestation. With respect to the type of physical exercise, the natural childbirth rate was improved the most by pelvic floor muscle training, general sports lessons, gymnastics, aerobic exercise, birthing ball movement, and yoga. As for the frequency of physical exercise, the natural childbirth rate was improved the most by at least 12 times per week, followed by 3-5 times per week, 6-8 times per week, and 9-11 times per week. In terms of the intensity of physical exercise, the natural childbirth rate was improved the most by moderate intensity of physical exercise. With regard to the duration of physical exercise, the natural childbirth rate was improved the most by physical exercise lasting for 30-<50 minutes per time, followed by less than 30 minutes per time, and at least 50 minutes per time. In respect to the number of weeks of conducting physical exercise, the natural childbirth rate was improved the most by physical exercise lasting for 8 or less than 8 consecutive weeks, followed by l7-24 weeks, 9-16 weeks, and 25-34 weeks. Funnel plot assessing publication bias of the studies was basically symmetrical in shape, indicating that the publication bias was generally weak. The overall quality of evidence concerning improvements in natural childbirth rate by physical exercise interventions in the studies was rated moderate.

The results show that proper physical exercise during pregnancy favorably affects the probability of natural childbirth. The natural childbirth probability could be positively influenced by some types of moderate-intensity physical exercise interventions, such as pelvic floor muscle training, general sports lessons, gymnastics, aerobic exercise, birthing ball movement, and yoga, if they are performed at least 12 times per week (30-<50 minutes each time) within 8 consecutive weeks after 24 weeks of gestation.

自然分娩是人类繁衍的正常生理过程，中国剖宫产率超出了世界卫生组织（WHO）提出的警戒线2倍多，而体育锻炼作为一种非药物性的健康干预方式，应引起相关部门的重视。

运用Meta分析方法检验妊娠期体育锻炼对自然分娩影响的干预效果，并提出最优的锻炼方案。

检索中国知网（CNKI）、中国生物医学文献服务系统（CBM）、维普网中文数据库和PubMed、EMBase、Web of Science、Cochrane Library英文数据库中有关妊娠期体育锻炼干预影响自然分娩结果的随机对照试验（其中干预组以体育锻炼干预为唯一干预方式，对照组进行常规护理知识教育或不进行有规律的体育锻炼），同时追踪相关系统评价所引用的参考文献，检索时间为1990—2021年。提取纳入文献资料，并对纳入文献进行方法学质量评价，采用RevMan 5.2软件进行Meta分析，运用GRADE工具对结局指标进行质量评价。

共纳入30篇文献。Meta分析结果显示，干预组自然分娩发生率高于对照组〔RR=1.34，95%CI（1.28，1.40），P<0.000 01〕。亚组分析结果显示，锻炼开始节点对自然分娩的干预效果从高到低依次为：>24周、13~24周、≤12周；锻炼内容对自然分娩的干预效果从高到低依次为：盆底肌训练、运动课、体操、有氧运动、分娩球、瑜伽；锻炼频率对自然分娩的干预效果从高到低依次为：≥12次/周、3~5次/周、6~8次/周、9~11次/周；中等强度的锻炼较低强度的锻炼对自然分娩具有更大的影响；锻炼时长对自然分娩的干预效果从高到低依次为：30~<50 min/次、<30 min/次、≥50 min/次；锻炼周期对自然分娩的干预效果从高到低依次为：≤8周、17~24周、9~16周、25~34周。绘制体育锻炼干预对孕妇自然分娩影响的漏斗图，结果显示，漏斗图左右两侧基本对称，发表偏倚较小。运用GRADE工具对结局指标进行质量评价，结果显示，妊娠期体育锻炼影响自然分娩的评级为中等级。

孕妇在妊娠期进行一定的体育锻炼对自然分娩结果具有良好的干预效果，且从妊娠期>24周开始锻炼、≥12次/周、30~<50 min/次、持续进行≤8周的中等强度的盆底肌训练、运动课、体操、有氧运动、分娩球以及瑜伽均对孕妇自然分娩的选择具有积极的影响。