Experimental study showed that adding fortifier and extra-hydrolysed proteins to preterm infant mothers' milk increased osmolality. - Rosas, R; Sanz, MP; Fernández‐Calle, P; Alcaide, MJ; Montes, MT; Pastrana, N; Segovia, C; Omeñaca, F; Sáenz de Pipaón, M (Acta Paediatrica, 2016)