Problems with assessing the effect of maternal nutrition and lactation performance are presented in relation to a conceptual mathematical ziggurat. Difficulties, variations and flows are to be found in stages of this sequence of "logic" [e.g., assessment of maternal nutrition, volume and composition of breast milk, nutritional satisfactions of the nursling). It is concluded that the various steps in this process of reasoning are subject to much more variation and adaptation than appreciated. Much so-called "faltering" in the second trimester is physiologically normal ("pseudo-faltering").
Recent developments in breastfeeding are reviewed in relation to species-specific adaptive suckling and the level of maturity of the newborn. Scientific advantages and advances are noted concerning biochemistry, protective substances, emotional differences, child spacing and economics. The significance of unimpaired maternal reflexes and the need for information is stressed with regard to successful lactation and as common causes of inadequacy. The components needed in varying degrees, in breastfeeding programmes are mentioned briefly.