Ikonen R, et al. - A cross-sectional study was carried out to depict preterm infants' mothers' expressing practices and exclusive utilization of mother's breast milk in neonatal intensive care settings, and also to investigate whether mothers' and infants' attributes are predictors of the mother's inadequate expressing practices and non-exclusive utilization of mothers' breast milk. Expression practices and utilization of own mother's milk, were suboptimal. High gestational age was related to both late expression initiation and non-exclusive breast milk use. The mothers maintained expression regardless of their well-being.