The Chiang Mai lactation project: study design and implementation

The Chiang Mai lactation project is a longitudinal field study of human lactation carried out among northern Thai women living in the Sanpatong area of Chiang Mai Province. Its aim was to measure the volume and composition of breast milk transferred from mothers to their infants in the first year postpartum, and to relate it to predictors of milk production, and to the growth of the child. Breast milk and supplementary food intake, and nursing patterns, were recorded over two consecutive 24-hour periods six times during the first year. Samples of breast milk and of supplementary foods were analysed for energy and protein. Supplementary foods were also analysed for bacterial contamination. The growth of the child was measured, and health assessed using a combination of health diaries and examination by a physician. Recruitment to the study was excellent. After recruitment, two subjects left the study area, but otherwise only two dropped out, so complete sets of data covering these variables are available for 58 of the 62 recruited subjects.