Abstract: Objective · To obtain the latest data on phospholipid composition of human milk in Shanghai and compare the differences in phospholipid composition at different lactation stages.  Methods · Healthy postpartum women who delivered full-term infants in the Obstetrical Department of Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine between April and July, 2016 were enrolled. The colostrum, transitional milk, and mature milk were collected at Day 3, 10, and 45 after delivering babies, respectively. Human milk fat was extracted with Folch’s method and phospholipids were separated with solid phase extraction (SPE). The phosphatidylethanolamine, phosphatidylcholine, and sphingomyelin were quantitatively analyzed with HPLC/VWD. The differences in phospholipid composition at different lactation stages were compared with univariate analysis of variance and GamesHomell test.  Results · One hundred women who provided at least one breast milk sample were enrolled. A total of 70 colostrum samples, 96 transitional milk samples, and 82 mature milk samples were collected. The total phospholipid content of mature milk [(281.93±118.54) μg/g] was significantly lower than that of colostrum [(381.99±205.90) μg/g]. At all lactation stages, the relative content of phosphatidylcholine was the highest (53.74%-59.36%), followed by sphingomyelin (28.12%-32.74%). The relative content of phosphatidylethanolamine was constant (P=0.617), the relative content of phosphatidylcholine gradually decreased (P=0.000), and that of sphingomyelin gradually increased (P=0.000) during the lactation.  Conclusion · Sphingomyelin and phosphatidylcholine are major components of human milk phospholipids. The amount of phospholipids varies during the lactation. The total amount of phospholipids is lower in mature milk than in colostrum and transitional milk. The relative content of phosphatidylethanolamine is consistent at all lactation stages, the relative content of phosphatidylcholine gradually decreases, and that of sphingomyelin gradually increases.

Key words: human milk, lactation, phosphatidylethanolamine, phosphatidylcholine, sphingomyelin