[Duration of breast feeding--which factors are significant?].

Duration of breast-feeding (BF) was studied in 249 randomly chosen healthy, term infants of Danish origin of which 81% participated. BF was initiated by 99.5% of the mothers. At three, six, and nine months, 71%, 52%, and 33%, respectively, were still BF. Only one infant (0.5%) was exclusively BF beyond the age of seven months. In a Cox multiple regression analysis of factors influencing duration of BF, we found a positive association with maternal education (p < 0.001), and age (p = 0.02), and a negative association with the amount of formula given at the maternity ward (p < 0.001). Six months after delivery 79% of the mothers with higher school education (> or = 12 years) were still BF, compared to 29% with a low school education (< or = 9 years). There is still a need for an increased effort to support mothers in BF to be focused on younger mothers with short school education. Formula supplements during the first days of life, given to 73% of the infants, were associated with shorter duration of BF and should be discouraged.