Impact of lactoferrin supplementation on fetal growth and birth weight: A comprehensive review

Background and Objective: Fetal growth and birth weight are key indicators of intrauterine wellbeing and may be influenced by biological, nutritional, and inflammatory factors. Lactoferrin is a multifunctional iron-binding glycoprotein with antimicrobial, anti-inflammatory, antioxidant, and immunomodulatory properties. This narrative review aimed to summarize and critically discuss clinical and preclinical evidence on lactoferrin supplementation during pregnancy in relation to fetal growth, birth weight, and developmental outcomes. Methods: A structured narrative review was conducted through searches of PubMed, Embase, Scopus, ProQuest Dissertations & Theses Global, and Google Scholar for studies published during the five years preceding the search date, up to 1 August 2025. Free-text keywords and controlled vocabulary terms related to lactoferrin, pregnancy, fetal growth, birth weight, and development were used. Reference lists and grey literature sources were also screened. Conclusions: Preclinical studies suggest that maternal lactoferrin supplementation may modulate neurodevelopmental pathways, reduce oxidative stress, and support brain integrity, without consistently increasing fetal or neonatal birth weight. Clinical studies, mainly involving women with iron deficiency, iron-deficiency anemia, hereditary thrombophilia, or infectious conditions, report improvements in maternal hematological parameters and reductions in inflammatory markers. Neonatal outcomes generally indicate adequate birth weight and gestational age, although a direct and consistent effect on fetal growth remains unproven. Lactoferrin may therefore act as a context-dependent modulator of fetal development rather than as a universal growth-promoting intervention. Further studies are needed to define optimal dosing, timing, target populations, and its potential role in clinical practice and maternal–fetal health policy.