BACKGROUND Preconception diet is a proposed modifiable risk factor for infertility. However, there is no official guidance for women in the preconception period as to which dietary approaches may improve fertility. OBJECTIVE AND RATIONALE A comprehensive synthesis of the relevant evidence is key to determine the potentially effective dietary patterns and components as well as evidence gaps, and to provide information for nutritional recommendations for couples planning a pregnancy. SEARCH METHODS In this systematic scoping review, four electronic databases (Medline and EMBASE via Ovid processing, CAB Direct, and CINAHL via EBSCO) were searched for observational studies (prospective and retrospective cohort, cross-sectional, and case–control studies) from inception to 27 September 2021. Eligible studies included women of reproductive age during the preconception period, and evaluated exposures related to preconception diet and outcomes related to fertility. Results were synthesized using a descriptive approach. OUTCOMES A total of 36 studies were eligible for inclusion (31 prospective, 3 cross-sectional, and 2 case–control studies) and were published between 2007 and 2022. Of the assessed dietary exposures, increased adherence to the Mediterranean diet displayed the strongest and most consistent association with improved clinical pregnancy rates. Reducing trans fatty acids (TFAs), saturated fatty acids, and discretionary food intake (fast food and sugar-sweetened beverages) were associated with improvements in live birth, clinical pregnancy rates, and related ART outcomes. The dietary components of seafood, dairy, and soy demonstrated inconsistent findings across the few included studies. WIDER IMPLICATIONS Due to heterogeneity and the limited available literature on most exposures, there is insufficient evidence to support any specific dietary approach for improving fertility. However, following some of the dietary approaches outlined in this review (anti-inflammatory diets, reducing TFA, and discretionary food intake) are consistent with broad healthy eating guidelines, have little to no associated risk, and offer a plausible set of possible benefits. This warrants further exploration in randomized controlled trials.

中文翻译：

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评估孕前饮食对女性生育能力的影响：观察性研究的系统范围审查

背景技术孕前饮食是一种可改变的不孕危险因素。然而，关于哪些饮食方法可以提高生育能力，目前还没有针对孕前期女性的官方指导。目标和理由 全面综合相关证据对于确定潜在有效的饮食模式和成分以及证据差距以及为计划怀孕的夫妇提供营养建议信息至关重要。搜索方法 在本系统范围界定综述中，从一开始就对四个电子数据库（通过 Ovid 处理的 Medline 和 EMBASE、CAB Direct 和通过 EBSCO 的 CINAHL）进行了观察性研究（前瞻性和回顾性队列、横断面和病例对照研究）的搜索至 2021 年 9 月 27 日。符合条件的研究包括孕前阶段的育龄妇女，并评估了与孕前饮食相关的暴露以及与生育力相关的结果。使用描述性方法综合结果。结果 共有 36 项研究符合纳入条件（31 项前瞻性研究、3 项横断面研究和 2 项病例对照研究），并于 2007 年至 2022 年期间发表。在评估的饮食暴露中，增加对地中海饮食的坚持显示出最强和最有效的结果。与改善临床妊娠率最一致的关联。减少反式脂肪酸 (TFA)、饱和脂肪酸和可自由支配的食物摄入量（快餐和含糖饮料）与活产率、临床妊娠率和相关 ART 结局的改善相关。海鲜、乳制品和大豆的膳食成分在少数纳入的研究中显示出不一致的结果。更广泛的影响 由于大多数暴露的异质性和现有文献有限，没有足够的证据支持任何特定的饮食方法来提高生育能力。然而，遵循本综述中概述的一些饮食方法（抗炎饮食、减少反式脂肪酸和酌情摄入食物）符合广泛的健康饮食指南，几乎没有相关风险，并且提供了一系列看似合理的可能益处。这值得在随机对照试验中进一步探索。