Narrative review: The role of maternal nutrition in recurrent miscarriage: From molecular pathways to clinical care gaps.

Recurrent miscarriage (RM), defined as three or more consecutive pregnancy losses before 24 weeks' gestation, represents a profound clinical and psychological challenge, affecting approximately 1-2% of couples. Despite standard investigation, up to 50% of cases remain unexplained, shifting focus towards modifiable environmental factors. Maternal nutrition, particularly micronutrient status, is a critical yet underexplored component influencing the biological pathways essential for early pregnancy success. This narrative review synthesises evidence on the role of nutrition in RM, focusing on molecular placental biology, clinical evidence of micronutrient deficiencies, and lived experiences of patients. We outline how key micronutrients, including folate, vitamin B12, vitamin D, and iron, act as upstream regulators of fundamental processes such as trophoblast invasion and differentiation, immune tolerance, and epigenetic regulation via microRNAs. Current evidence, though limited and often observational, consistently shows a high prevalence of suboptimal micronutrient status in women with RM compared with the general obstetric population. However, a significant translation gap exists. UK clinical care for RM does not routinely incorporate detailed nutritional assessment or personalised dietary guidance, despite strong biological plausibility and evidence of patient preference for such support. This review argues for a paradigm shift, advocating the integration of comprehensive nutritional profiling and the triangulation of dietary intake, serum biomarkers, and pregnancy outcomes into specialised care pathways for women with RM. Future research should employ robust mixed-methods designs to establish causality and develop effective, patient-centred nutritional interventions aimed at mitigating this pregnancy complication.