The Dietary Inflammatory Index as a predictor of pregnancy outcomes: Systematic review and meta-analysis

Unhealthy diets have been linked to low-grade chronic inflammation, a condition known to play a role in the pathophysiology of non-communicable diseases as well as pregnancy complications. The Dietary Inflammatory Index (DII) is a tool for evaluating the inflammatory potential of various diets. The goal of this systematic review and meta-analysis is to assess the current state of evidence on the use of DII as a predictor of pregnancy outcomes in pregnant women. This study was developed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PROSPERO, number CRD42021288966). DII was evaluated as a predictor of obstetric complications in observational studies. The search was conducted in PubMed/Medline, Embase, and Web of Science. Data from eligible studies were extracted independently by two reviewers. The Newcastle-Ottawa Scale was used to assess the methodological quality of the studies. A total of eight studies were eligible for the review. In a meta-analysis of continuous and categorical variables, DII was a predictor of any obstetric complications [mean difference: 0.39, 95 %CI 0.02-0.75, (p = 0.04); and odds ratio: 1.24, 95 %CI 1.11-1.40, (p = 0.0002)]. High DII was associated with pregnancy complications, particularly preeclampsia/hypertensive disorder of pregnancy and preterm birth. The DII is a tool that can assist in the food and therapeutic planning of pregnant women with obstetric risks. Well-designed clinical trials are necessary, especially studies that focus on recurrent pregnancy losses and implantation failures.