Duration of breast feeding and risk of developmental delay in Taiwanese children: a nationwide birth cohort study.

The purpose of this study was to examine the relationship between duration of breast feeding and four developmental domains: gross motor, fine motor, language, and personal/social skills. This study included 14,621 infants from birth to 18 months of age. In the Taiwan Birth Cohort Study, four developmental screening items adapted from the Denver Development Screening Test were most appropriate for children aged 15 to 18 months. The proportion of young children who had mastered specific milestones increased consistently with longer duration of breast feeding. The adjusted odds ratios of the risk of developmental delay for the longest duration of breast feeding vs. never breast-fed were 0.69 [95% confidence interval (CI) 0.57, 0.83] for gross motor, 0.64 [95% CI 0.53, 0.77] for fine motor, 0.74 [95% CI 0.60, 0.91] for language, and 0.76 [95% CI 0.64, 0.90] for personal/social skills. Regardless of when the mothers returned to work, duration of breast feeding was found to have an inverse association with developmental delay in young children. The protection against developmental delays remained significant for those children who were breast-fed for more than 6 months. Children who were breast-fed for longer than 6 months had a lower risk of developmental delay than those who were never breast-fed. These data support the hypothesis that duration of breast feeding is positively related to young children's neurodevelopment.