Maternal nutrition and developmental programming during the first 1000 days

The first 1000 days—spanning from conception to approximately a child’s second birthday (approximately 24 months)—represent a critical period of developmental plasticity during which maternal, foetal and early postnatal nutrition profoundly influence growth, neurodevelopment, immune maturation and lifelong metabolic health. This narrative review synthesises mechanistic, epidemiological and interventional evidence linking maternal nutrition before conception, during pregnancy, and throughout lactation, infancy, and toddlerhood with offspring growth and neurodevelopment outcomes. The review also addresses long-term, intergenerational, and transgenerational consequences of early-life malnutrition, including cardiometabolic disease risk and cognitive outcomes later in life. A narrative synthesis of human studies, systematic reviews, and meta-analyses published up to 2025 was conducted using PubMed, Scopus, and Cochrane databases. Priority was given to systematic reviews, meta-analyses, and randomised controlled trials. Maternal undernutrition, micronutrient deficiencies, and excess adiposity substantially contribute to adverse birth and early childhood outcomes worldwide. Mechanistic pathways include epigenetic modification, placental nutrient transport, endocrine and inflammatory signalling, and postnatal nutritional exposures. Evidence from randomised trials supports the effectiveness of multiple micronutrient supplementation (MMS), calcium, docosahexaenoic acid (DHA), vitamin D, balanced energy–protein (BEP) interventions, and small-quantity lipid-based nutrient supplements (SQ-LNS) in improving birth outcomes and early neurodevelopment, particularly in nutritionally vulnerable populations. Optimising nutrition across the first 1000 days is essential for maximising developmental potential and interrupting intergenerational and transgenerational cycles of malnutrition and non-communicable disease.