Can Dietary Patterns Impact Fertility Outcomes? A Systematic Review and Meta-Analysis

Abstract

There are conflicting results on the effect of diet on fertility. This study aimed to assess the effect of different dietary patterns on fertility outcomes in populations who conceive spontaneously and those requiring assisted reproductive technology (ART). A systematic search and meta-analysis were performed for studies investigating dietary patterns or whole diets in reproductive aged women requiring ART or conceived naturally. Outcomes were live births, pregnancy rates and infertility rates. In amount of 15,396 studies were screened with 11 eligible studies. Ten different diet patterns were grouped broadly into categories: Mediterranean, Healthy or Unhealthy. For the Mediterranean diet, on excluding high risk-of-bias studies (n = 3), higher adherence was associated with improved live birth/pregnancy rates in ART [OR 1.91 (95% CI 1.14-3.19, I² 43%)] (n = 2). Adherence to various Healthy diets was associated with improved ART outcomes (ProFertility diet and Dutch Dietary Guidelines) and natural conception outcomes (Fertility diet). However, due to the variability in Healthy diets' components, results were not pooled. Studies demonstrated preliminary evidence for the role of dietary patterns or whole diets in improving pregnancy and live birth rates. However, due to heterogeneity across the literature it is currently unclear which diet patterns are associated with improvements in fertility and ART outcomes.

Keywords: Mediterranean diet; diet; diet pattern; fertility; infertility; live birth; pregnancy; systematic review; whole diet.

Figure 1

PRISMA diagram for the literature search process.

Figure 2

Forest plot of studies comparing groups of high and low adherence to Mediterranean diets and ART outcomes. Random effects model meta-analysis of crude OR, Vujkovic et al. highest to lowest tertile [14], Karayiannis et al. highest to lowest tertile [40], Ricci et al. [43], Gaskins et al. [21], highest to lowest quartile, Sun et al. higher to lower half [42]. OR, odds ratio. CI, confidence interval.

Figure 3

Forest plot of studies comparing groups of high and low adherence to various Healthy diets and ART outcomes. Random effects meta-analysis of crude OR, Vujkovic et al. [14] and Twigt et al. [35] highest to lowest tertile, Sugawa et al. [41] and Gaskins et al. [21] highest to lowest quartile. OR, odds ratio. CI, confidence interval.

Figure 4

Funnel plot of both natural conception and ART for the dietary comparison on primary outcomes. Studies by Vujkovic et al. (2010) [14], Gaskins et al. (2019) [21] use published results of Mediterranean diet. Studies by Sugawa et al. (2018) [41] uses Vegetables and Seafood diet, Gaskins et al. (2014) [44] and Chavarro et al. (2007) [15] use Fertility diet. All other studies, Twigt et al. (2012) [35], Karayiannis et al. (2018) [40], Sun et al. (2019) [42], Ricci et al. (2019) [43], Toledo et al. (2011) [46] and Hartman et al. (2021) [45] assessed single diet patterns, which are included in the funnel plot. Studies by Gaskins et al. (2014) [44], Toledo et al. (2011) [46], Chavarro et al. (2007) [15], Hartman et al. (2021) [45] published effects of infertility rates/pregnancy loss in natural conception, reciprocals of published results are presented here in funnel plot.