Continuity of breastfeeding is infrequent and indeterminate. Evidence is lacking regarding factors associated with breastfeeding at different postpartum time points. This prospective study investigated the change in, and correlates of, breastfeeding practices after delivery at a hospital and at 1, 3, and 6 months postpartum among first-time mothers. We followed a cohort of 300 primiparous mothers of Taiwan who gave birth at two hospitals during 2010-2011. Logistic and Cox regression analyses were performed to determine factors that were correlated with breastfeeding practices. In the study sample, the rate of exclusive breastfeeding during the hospital stay was 66%; it declined to 37.5% at 1 month and 30.2% at 3 months postpartum. Only 17.1% of women reported continuing breastfeeding at 6 months. Early initiation of breastfeeding, rooming-in practice, and self-efficacy were significantly related to exclusive breastfeeding during the hospital stay. After discharge, health literacy, knowledge, intention, and self-efficacy were positively and significantly associated with breastfeeding exclusivity. Later initiation (hazard ratio=1.53; 95% confidence interval, 1.05, 1.97), shorter intention (hazard ratio=1.42; 95% confidence interval, 1.13, 1.68), and self-efficacy (hazard ratio=0.98; 95% confidence interval, 0.96, 0.99) were important predictors of breastfeeding cessation within 6 months of delivery. Continuous breastfeeding practice for 6 months is challenging and difficult for new mothers. Results showed that factors related to breastfeeding varied over time after delivery. Interventions seeking to sustain breastfeeding should consider new mothers' needs and barriers at different times.