Colorful Concerns: Exploring Perceived Reasons for and Maternal–Infant Reactions to Human Milk Color Changes Through a Cross-Sectional Study

Background: Human milk color variation has been described in case reports, but no large-scale studies have characterized this phenomenon. Abrupt changes in milk color can be unsettling for parents and healthcare providers, potentially leading to unnecessary breastfeeding disruption. Research Aim: The objectives of this study were to characterize self-reported human milk color variations, explore maternal perceptions of their causes, and examine factors associated with maternal breastfeeding routine changes following color variation. Methods: An exploratory cross-sectional online survey collecting self-reported observations of milk color changes was distributed via the InfantRisk Center from March 2022 to January 2023. Descriptive analyses characterized color variations and maternal responses ( n = 430). Multivariable logistic regression identified factors associated with breastfeeding routine change ( n = 277). Results: Green was the most commonly reported color ( n = 174), followed by blue, yellow, and red. Most color changes lasted 1–3 days. Perceived causes included infection ( n = 256), food ( n = 274), vaccination ( n = 43), medication/supplement ( n = 60), and blood or trauma ( n = 52). Most mothers were not concerned ( n = 245), and no mother stopped breastfeeding entirely. Red milk was the strongest predictor of behavior change (adjusted odds ratio [aOR] = 19.5; 95% confidence interval [CI] 4.9–77.2), followed by fear of harming the infant (aOR = 2.9, 95% CI 1.7–5.1) and maternal age (aOR = 1.2, 95% CI 1.03–1.30). Education was protective. Prior breastfeeding experience, infant health, infant age, and healthcare provider recommendation were not associated with breastfeeding behavior change. Conclusion: Human milk color variation is more common and varied than previously documented. Anticipatory guidance normalizing color variation may reduce unnecessary fear across all parity groups.