Dietary inflammatory index during pregnancy: associations with maternal metabolic disorders and adverse birth outcomes—a systematic review

Maternal nutrition plays a significant role in both maternal and offspring health. The Dietary Inflammation Index (DII) was developed as a comprehensive tool to evaluate the inflammatory potential of dietary patterns. This systematic review aimed to synthesize existing evidence regarding the association between the Dietary Inflammatory Index (DII) during pregnancy and maternal metabolic disorders as well as adverse birth outcomes. Relevant observational studies published up to December 2025 were systematically searched in PubMed, Embase, and Web of Science. Two reviewers independently performed study selection and data extraction. Disagreements were adjudicated by a third senior reviewer. Of 346 records screened, 8 studies were finally included. Risk of bias was assessed using the Newcastle–Ottawa Scale (NOS). Due to clinical heterogeneity across studies, a narrative synthesis was conducted to evaluate the association between Dietary Inflammatory Index (DII) scores and pregnancy-related outcomes. Higher DII scores were significantly associated with increased risks of gestational diabetes mellitus (aOR = 1.43, 95% CI: 1.05–1.95), hypertensive disorders of pregnancy (aOR = 1.26, 95% CI: 1.03–1.54), preeclampsia (aOR = 2.18, 95% CI: 1.52–3.13), and hyperemesis gravidarum (aOR = 1.65, 95% CI: 1.04–2.62). Regarding offspring outcomes, higher DII was linked to increased childhood obesity(OR = 1.09, 95%CI: 1.00–1.19) and neurodevelopmental delay risk (aOR = 1.23, 95% CI: 1.10–1.39), while no significant association was found with offspring asthma/wheeze (aOR = 1.15, 95% CI: 0.99–1.33). This systematic review provides a comprehensive synthesis of current literature, specifically focusing on the quantitative relationship between DII and both maternal metabolic disorders and a wide spectrum of offspring birth outcomes. Higher DII scores increased risks of gestational diabetes, preeclampsia, and hyperemesis gravidarum. While associated with increased childhood adiposity and neurodevelopmental risk, DII showed no clear effect on birth weight or offspring asthma. These findings suggest that adopting anti-inflammatory dietary patterns during preconception and pregnancy may mitigate pregnancy-related complications. Future large-scale prospective studies employing standardized DII thresholds are required to confirm these associations and inform clinical dietary guidelines.