Measuring short-term rates of milk synthesis in breast-feeding mothers.

A Moire contouring method was used to measure changes in the volume of the breast between infant feeds. A tungsten-halogen light source obliquely illuminated the breast through a moving Moire grid to produce contour shadows on the breast. Photographs of the Moire topographs were analysed to obtain three-dimensional co-ordinates of transverse sections through the breast. The cross-sectional areas were calculated using the trapezoidal rule and volumes were calculated by multiplying these areas by their vertical separation. The precision of the method was found to be dependent on the subject repositioning accurately. With careful control over subject posture and position the relative standard deviation was 1.8%, but without careful repositioning the relative standard deviation was 10%. The Moire topography method was accurate; the mean difference between changes in the volume of the breast after breast feeding as measured by the Moire topography method and test weighing was 0.34 +/- 7.26 ml (n = 21). For two women, the rate of increase in the volume of the right breast was found to range from 13 to 40 ml/h.