Introduction: Breast-feeding practices (BFPs) can be assessed by interviewing the mother about current feeding practices and with a 24-hour recall. It is crucial to establish the accuracy of these methods, which are commonly used by public health decision makers to design health policies aimed at increasing exclusive breast-feeding rates. Objective: We aimed to validate 2 self-report BFP instruments using the dose-to-mother deuterium oxide turnover technique (DMDOT) as the reference method. Methods: Breast-feeding practices were assessed by interviewing the mother about current feeding practices and with a 24-hour recall in 36 Guatemalan mother-infant pairs. The validity of these instruments was assessed using DMDOT as the reference method. Results: Both self-report instruments overestimated exclusively breast-fed (EBF) infants. Infants classified as EBF were 50% by the reported current feeding practice, 61% by the 24-hour recall, and only 36% using DMDOT. Sensitivity to detect EBF infants from the mother's self-report was 92% (95% CI: 62%-99%) while from the 24-hour recall was 100% (95% CI: 72%-100%, P < .01). However, specificity for both instruments was low, at 74% (95% CI: 51%-89%) for reported current feeding practice and at 61% (95% CI: 39%-79%) for the 24-hour recall (P < .01). Conclusion: Both reported current feeding practice and the 24-hour recall instruments overestimated exclusive breast-feeding. Nevertheless, the use of reported current feeding practice provided more accurate data to assess BFPs in a public health setting. Furthermore, population-based surveys should consider the overestimation of exclusive breast-feeding caused when using these BFP instruments.
