To determine the effect of intention to breast-feed on short-term breast-feeding outcomes in women delivering term and preterm infants.

Data from the US Centers for Disease Control and Prevention's Pregnancy Risk Assessment Monitoring System (PRAMS) for three states, Ohio, Michigan and Arkansas, during 2000–2003 were analysed. SAS 9·1·3 and SUDAAN 10 statistical software packages were used for analyses.

Arkansas, Michigan and Ohio, USA.

Mothers of recently delivered infants, selected by birth certificate sampling.

Of 16 839 mothers included, 9·7 % delivered preterm. Some 52·2 % expressed definite intention to breast-feed, 16·8 % expressed tentative intention, 4·3 % were uncertain and 26·8 % had no intention to breast-feed. Overall 65·2 % initiated breast-feeding, 52·0 % breast-fed for ≥4 weeks and 30·8 % breast-fed for ≥10 weeks. Women with definite intention were more likely to initiate (OR = 24·3, 95 % CI 18·4, 32·1), to breast-feed for ≥4 weeks (OR = 7·12, 95 % CI 5·95, 8·51) and to breast-feed for ≥10 weeks (OR = 2·75, 95 % CI 2·20, 3·45) compared with women with tentative intention. Levels of intention did not differ between women delivering preterm and term. Women delivering at <34 weeks were more likely to initiate breast-feeding (OR = 2·24, 95 % CI 1·64, 3·06) and to breast-feed for ≥4 weeks (OR = 2·58, 95 % CI 1·96, 3·41), but less likely to breast-feed for ≥10 weeks (OR = 0·55, 95 % CI 0·44, 0·68), compared with those delivering at term. Women delivering between 34 and 36 weeks were less likely to breast-feed for ≥10 weeks than those delivering at term (OR = 0·63, 95 % CI 0·49, 0·81).

Prenatal intention to breast-feed is a powerful predictor of short-term breast-feeding outcomes in women delivering both at term and prematurely.