Total nitrogen and electrolyte levels in colostrum and transition human milk

The objective of this research was to study the composition of human milk in terms of protein levels and levels of the electrolytes sodium, potassium, calcium, magnesium, phosphorus and chloride in colostrum 48-72 hours post-partum, and in the transition milk (96 +/- 9 hours, 120 +/- 9 hours and 144 +/- 9 hours post-partum) of mothers who had fullterm and pre-term deliveries. The mothers were kept in the hospital with the objective to control a few important lactation parameters such as exercising or resting conditions, sleep, nutrition and suckling stimulation. Only low socioeconomic level mothers took part in the study. The initial period of lactation was studied because this is the time when secretion suffers rapid changes, going from colostrum to transition milk, and then to mature milk. The results observed for the different times and for the two groups were compared both within and between groups. No significant differences were obtained for any of the comparisons, except for transitory oscillations in potassium, calcium, chloride and phosphorus levels observed within groups. In general, it can be said that there was no variation between colostrum and transition milk for the mothers who delivered at full term or pre-term. No differences were found either when the groups were compared at the different times post-partum. This means that, under the conditions used in this study, milk did not vary as its type naturally changed (from colostrum to transition milk) for the two groups and that the levels of the constituents studied also remained unchanged when studied as a function of full-term or pre-term delivery.(ABSTRACT TRUNCATED AT 250 WORDS)