Methods and device for determining efficiency of lactation

A method for determining inadequate lactation in a female subject, the method comprising:

• determining an expression of a physicochemical parameter of a breast milk sample obtained from the subject at a time point after delivery, and
• determining whether the subject is inadequately lactating by comparing the expression of the physicochemical parameter of the breast milk sample with an expression of the physicochemical parameter of breast milk sample(s) obtained from adequately lactating subjects at the same time point after delivery or by comparing a change in expression of a physicochemical parameter of two or more breast milk samples obtained at two or more time points, with a change of an expression of the physicochemical parameter of breast milk sample(s) obtained from adequately lactating subjects, at the two or more time points;
• wherein inadequate lactation comprises or is associated with reduced lactation efficiency, delayed lactogenesis II (DLII), inadequate lactogenesis III or reduced milk production.