Background and AimEvidence-based knowledge of how to guide the mothers of preterm infants in breastfeeding establishment is contradictive or sparse. The aim was to investigate the associations between pre-specified clinical practices for facilitating breastfeeding, and exclusive breastfeeding at discharge as well as adequate duration thereof.MethodsA prospective survey based on questionnaires was conducted with a Danish national cohort, comprised of 1,221 mothers and their 1,488 preterm infants with a gestational age of 24–36 weeks. Adjusted for covariates, the pre-specified clinical practices were analysed by multiple logistic regression analyses.ResultsAt discharge 68% of the preterm infants were exclusively breastfed and 17% partially. Test-weighing the infant, and minimizing the use of a pacifier, showed a protective effect to exclusive breastfeeding at discharge (OR 0.6 (95% CI 0.4–0.8) and 0.4 (95% CI 0.3–0.6), respectively). The use of nipple shields (OR 2.3 (95% CI 1.6–3.2)) and the initiation of breast milk expression later than 48 hours postpartum (OR 4.9 (95% CI 1.9–12.6)) were associated with failure of exclusive breastfeeding at discharge. The clinical practices associated with an inadequate breastfeeding duration were the initiation of breast milk expression at 12–24 hours (OR 1.6 (95% CI 1.0–2.4)) and 24–48 hours (OR 1.8 (95% CI 1.0–3.1)) vs. before six hours postpartum, and the use of nipple shields (OR 1.4 (95% CI 1.1–1.9)).ConclusionEarly initiation of breast milk pumping before 12 hours postpartum may increase breastfeeding rates, and it seems that the use of nipple shields should be restricted. The use of test-weighing and minimizing the use of a pacifier may promote the establishment of exclusive breastfeeding, but more research is needed regarding adequate support to the mother when test-weighing is ceased, as more of these mothers ceased exclusive breastfeeding at an early stage after discharge.