William Butz

The Contraceptive Role of Breastfeeding

We review (1) neuro-hormonal mechanisms by which breastfeeding postpones the return of ovulation and menstruation after birth, and (2) various statistical procedures used to analyse this effect in human populations. This review reveals that the biology and the statistical procedures are incompatible. We propose a statistical approach, compatible with present knowledge of physiology, that differentiates between ovulation-inhibiting mechanisms at birth and the weakening of these inhibitions thereafter, so that it is possible to investigate the effects on these mechanisms due to breastfeeding and to other determinants such as mothers age. An empirical test with typical recall data indicates that full breastfeeding postpones ovulation longer than does supplemented breastfeeding, and that both have stronger contraceptive effects than has previously been thought.

Measurement of Health and Nutrition Effects of Large-Scale Nutrition Intervention Projects

Increasingly the nutritional impact of complex intervention packages is being sought. Typically these complex interventions include intentional changes in the economic, social and political environment as well as in medical and nutritional factors. We are concerned in this paper with the critical issues of the choice of indicators necessary to evaluate these complex interventions with multiple treatments.

The Effects of Nutrition and Health on Fertility: Hypotheses, Evidence, and Interventions.

The relationship between nutrition socioeconomic development and fertility is logically examined a model describing the interaction between the variables is presented and policy implications flowing from this model are discussed. From a biological standpoint improvements in health and nutrition would be expected to have a positive affect on reproductive capacity; however improved standards of living are negatively related to fertility. Therefore behavioral factors and not biological factors must account for the observed negative relationship. The behavior of poor people is rational and oriented toward maintaining an equilibrium between resource allocation and production. They retain this balance by adhering to principles developed over time and found to be effective under existing environmental conditions. For example the allocation of food resources is based on the time-tested principle that those family members most involved in production should receive the largest share of the food supply in times of scarity. Given the conditions under which these individuals live this allocation decision makes sense. Similarly the number of children in a family is considered to be more important than the quality of life for these children. Having many children even if these children suffer from malnutrition and lack an education contributes more toward the productive capacity of the family than having 1 or 2 healthy educated children under existing economic conditions. To expect parents living in these situations to allocate resources for the improvement of the nutritional status of infants is to expect them to act irrationally. Changing the environment in which these individuals live is the only way to induce them to change. If new conditions create a need for healthy educated children parents will alter the way they allocate resources. For example if new jobs requiring intellectual skills and improved agricultural technology requiring capital investment are made available the existing allocation system will be thrown out of balance; parents will respond by reallocating resources so as to take advantage of the new opportunities and reestablish the balance between resources and production by applying new principles more in tune with the environmental changes. This model based on the assumption that the peasant farmer is rational has policy implications which differ radically from the policy implications flowing from the backward peasant model.

ECONOMIC ASPECTS OF BREAST-FEEDING

For thousands of years, the popularity of breast-feeding among women of different cultures has fluctuated widely (1, 2, 3, 4). The longest known trend in this history has occurred in Western Europe and North America during the last century, when increasing proportions of women have failed to nurse their infants at all. The mean length of both full and partial breast-feeding of those who nursed has also steadily declined during this period (5, 6, 7, 8, 9, 10). More recently, a pervasive decline in breast-feeding activity is also underway in urban areas of many less developed countries, with similar tendencies suggested in some rural areas as well (11, 12, 13, 14).