A NOVEL METHOD FOR ESTIMATING NIGHT-TIME BREAST MILK INTAKE

Abstract

Indirect test weighing (TTW), for estimating overnight (o'nt) breast milk intake, is based on separate weighings of mother and infant before and after night-time sleep. Weight changes due to the exchange of milk are reciprocal, so that if all other sources of weight change (eg urine loss, suppl. fluid intake) are either controlled or measured, the difference between the mother's o'nt weight loss and her infant's o'nt weight gain gives a measurement of their combined Evaporative Water Loss (EWL). The proportion of the combined EWL due to the infant is then partitioned out as a function of the relative Metabolic Body Size (body weight to the power of 0.73) of mother and infant, and added to the infant's actual o'nt weight gain to provide the estimate of o'nt breast milk intake. Validation studies, conducted in Thailand, in which ITW was compared with direct test weighing, are reported for 13 infants over 3 nights at 5 days of age, and for 19 infants over 2 nights at 6 weeks and over. The regression equations for estimated milk intake against measured milk intake at the two ages are:The results show that this method can predict thé overnight milk intake of an individual infants to within 30g on 95% of occasions, making it suitable for use in both temperate urban and tropical rural locations, where, when a mother and infant sleep together at night, direct test weighing would often be impracticable.