It is well documented that obesity decreases natural fertility among men and women as well as pregnancy chances after conventional infertility and assisted reproductive technology (ART)–based treatments. Moreover, pregnancy complications are increased in women with overweight and obesity. General guidelines on the treatment of obesity recommend lifestyle intervention, including diet and exercise as the first-line treatment, coupled with or without medical treatments, such as weight loss medication or bariatric surgery, to reduce complications of obesity in adults. In the context of infertility in various countries and infertility clinics, there is a body mass index limit for public refund of infertility treatment of women with obesity. In this respect, it is important to investigate the evidence of effects of lifestyle intervention preceding infertility treatment on reproductive outcomes. The combined results of 15 randomized controlled trials (RCTs) of the effectiveness of preconception lifestyle intervention on reproductive outcomes documented in the latest systemic review and meta-analysis, together with the most recent RCT performed in 2022 are discussed. The current evidence suggests that greater weight loss and increase in clinical pregnancy, live birth, and natural conception rates after lifestyle intervention compared with no intervention were observed, but it seems no beneficial effect of lifestyle intervention preceding ART was observed on these parameters. With respect to potential harm of lifestyle intervention, there is no significant increased risk of early pregnancy loss, although the most recent RCT (not included in the systematic review and meta-analysis) showed a trend toward an increased risk. Complications during pregnancy, such as early pregnancy loss and maternal as well as fetal and neonatal complications, are underreported in most studies and need further analysis in an individual participant data meta-analysis. Limitations of the studies as well as future perspectives and challenges in this field of research will be highlighted.

有据可查的是，肥胖会降低男性和女性的自然生育能力以及传统不孕症和基于辅助生殖技术 (ART) 治疗后的怀孕机会。此外，超重和肥胖的妇女妊娠并发症增加。肥胖治疗的一般指南建议生活方式干预，包括将饮食和运动作为一线治疗，结合或不结合药物治疗，如减肥药物或减肥手术，以减少成人肥胖的并发症。在各国的不孕症和不孕症诊所的背景下，肥胖女性不孕不育治疗的公费退款都有体重指数限制。在这方面，重要的是调查不孕症治疗前生活方式干预对生殖结果影响的证据。讨论了最新系统评价和荟萃分析中记录的关于孕前生活方式干预对生殖结果有效性的 15 项随机对照试验 (RCT) 的综合结果，以及 2022 年进行的最新随机对照试验。目前的证据表明，与不干预相比，生活方式干预后体重减轻更多，临床妊娠率、活产率和自然受孕率增加，但似乎没有观察到在 ART 之前进行生活方式干预对这些参数有有益影响。关于生活方式干预的潜在危害，早孕流产的风险没有显着增加，尽管最近的随机对照试验（未包括在系统评价和荟萃分析中）显示出风险增加的趋势。怀孕期间的并发症，例如早孕流产和母体以及胎儿和新生儿并发症，在大多数研究中都被低估了，需要在个体参与者数据荟萃分析中进一步分析。将强调研究的局限性以及该研究领域的未来前景和挑战。