this study was conducted in pregnant women who are still lactating to study the effects of a new pregnancy on some milk constituents. It was found that for women pregnant at 6 months or more , the breast milk constituents undergo important changes with increase in milk protein and sodium & decreas in breast fat which is reflected on endandgering the kidneys of the lactating infant as well as depriving him from important energy source that is milk fat. So recommend weaning of a lactating infant at 6 months duration of a new pregnancy