All issues > Volume 25(1); 1982

Original Article

J Korean Pediatr Soc. 1982;25(1):1-7. Published online January 31, 1982.

Changes in Na and K Concentrations in Human Milk: at different stage of lactation.

Byung Ryong Lee¹, Jae Sook Ma¹, Chull Sohn¹

¹Department of Pediatrics, Chonnam University Medical School, Korea.

Abstract

The concentrations of Sodium and Potassium were measured by flame photometer in the human for milk obtained at clostral(1st 5days postpartum), early transitional (2nd 5days postpartum), late transitional (11th to 29th day postpartum) and mature milk period (1to 15 months postportum) from 92 healthy nursing mothers who delivered at term. The results were summerized as follows: 1) The concentrations of Na and K at different stages of lactation showed the highest value in colostrum, tended to decrease therafter and maintained the lowest and nearly constant value in mature milk(.01 2) Average Na and K concentrations(Mean+/-S.D., mEq/L) at different stages of lactation were colostrum : 20.8+/-4.47, 15.9+/-3.17, early transitional milk : 15.3+/-4.73, 14.2+/-3.03, late transitional milk : 11.7+/-4.28, 12.8+/-3.40, and mature milk : 8.1+/-3.59, 11.2+/-2.88 respectively. 3) The content of Na and K among primi-and multiparae showed the highest value in colostrum, also tended to decrease therafter, and maintained the lowest value in mature milk. No statistical significance was found between the concentrations of Na and K at different stages of lactation between primi-and multiparae(p>.05). 4) Definite inverse relationship could be established between Na and K concentrations and days of lactation(Na:r=-0.6, p<.001, K:r=0.4, p<.001). 5) The Mean Na and K concentration in late transitional milk showed the most consistent percentage decrease that in colostrum.

Keywords :Sodium;Potassium;Human milk;Colostrum;Early and late transitional;Mature milk