RESUMO
OBJECTIVE: To quantify optimal minimum durations of exclusive breastfeeding associated with maintenance of any breastfeeding at 15 time points during the first year of life. STUDY DESIGN: Mothers (n = 1189) from the prospective Infant Feeding Practices Study II cohort who initiated exclusive breastfeeding with healthy term infants were included. In a 80:20 split-sample validation study, receiver operating characteristic curves estimated optimal minimum durations of exclusive breastfeeding needed to predict maintenance of any breastfeeding at 15 time points during the first year (n = 951). Logistic regression estimated the predictive performance of the identified thresholds adjusted for maternal age, race, education, parity, support system, and return-to-work status. Results were validated in the remaining 20% (n = 238). RESULTS: Optimal minimum durations ranged from 4.0-17.1 weeks of exclusive breastfeeding associated with maintenance of any breastfeeding at 15 time points. All estimated threshold durations were statistically significant after adjustment. CONCLUSIONS: Using a methodological approach unique to breastfeeding duration research, the authors report optimal durations of exclusive breastfeeding associated with duration of any breastfeeding at time points throughout the first year. Perinatal clinicians, pediatricians, lactation professionals, policymakers, researchers, and families might apply these findings to achieve desirable collective breastfeeding duration outcomes.