Preconception nutritional supplementation and behavioral interventions and their association with maternal and...

BackgroundPreconception health influences pregnancy outcomes, with poor nutrition and health-related behaviors linked to anemia, preeclampsia, and fetal growth restriction. Despite increasing attention to these adverse outcomes, evidence on preconception nutritional and behavioral interventions remains limited, fragmented, and inconsistently synthesized.ObjectivesTo synthesize evidence on the role of preconception nutritional supplementation and behavioral interventions in supporting maternal and neonatal health outcomes.MethodsWe conducted a systematic review and meta-analysis following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines with the protocol registered in PROSPERO (#CRD42024592645). Studies published from the inception to October 1, 2024, were identified through six databases. A total of 24 studies met the eligibility criteria, which included randomized, non-randomized, and controlled before-after studies involving women aged 18-45 planning pregnancy or interconception period. Preconception interventions included nutritional supplementation (e.g., folic acid, calcium, multiple micronutrients) and behavioral/lifestyle strategies (e.g., counseling, diet, physical activity). Findings were analyzed separately by intervention type and outcome. Two reviewers independently screened studies and extracted data. Meta-analyses were conducted using RevMan software. Risk of bias was assessed using Cochrane RoB 2 and ROBINS-I, and certainty of evidence was rated using Grading of Recommendations, Assessment, Development, and Evaluation (GRADE).ResultsThe included studies suggested that lifestyle interventions reduced the risk of gestational diabetes mellitus (GDM) with Risk Ratio (RR): 0.76; 95% Confidence Interval (CI): 0.60-0.95), lowered gestational weight gain (GWG) with Mean Deviation (MD): -3.88 kg; 95% CI: -10.53 to -4.75), and improved GWG adequacy (RR: 1.62; 95% CI: 1.17-2.25). Nutritional supplementation were associated with reduced GDM risk (RR: 0.55; 95% CI: 0.43-0.71), increased birth weight by 72.26 g (95% CI: 47.40-97.12; I² = 96%), reduced preeclampsia risk with calcium (RR: 0.71; 95% CI: 0.54-0.92), and lowered neurodevelopmental disorder risk with folic acid/multivitamin use (RR: 0.14; 95% CI: 0.11-0.18). No pooled or synergistic association across intervention categories was estimated.ConclusionOutcome-specific evidence suggests that preconception nutritional and behavioral interventions are associated with improvements in selected maternal and neonatal outcomes. However, heterogeneity and limitations of underlying studies constrain causal inference, underscoring the need for rigorous longitudinal and integrated intervention research.