Patricia L. Johnson

Lactation and birth spacing in highland New Guinea.

The effects of infant suckling patterns on the post-partum resumption of ovulation and on birth spacing are investigated among the Gainj of highland New Guinea. Based on hormonal evidence the median duration of lactational anovulation is 20.4 months accounting for about 75% of the median interval between live birth and next successful conception (i.e. resulting in live birth). Throughout lactation suckling episodes are short and frequent the interval changing slowly over time from 24 minutes in newborns to 80 minutes in 3-year olds. Maternal serum prolactin concentrations decline in parallel with the changes in suckling patterns approaching the level observed in non-nursing women by about 24 months postpartum. A path analysis indicates that the interval between suckling episodes is the principal determinant of maternal prolactin concentration with time since parturition affecting prolactin secretion only in so far as it affects suckling frequency. The extremely prolonged contraceptive effect of breastfeeding in this population thus appears to be due to 1) a slow decline in suckling frequency with time since parturition; and 2) absence of a decline over time in hypothalamic-pituitary responsiveness to the suckling stimulus. (authors modified)

Demographic and endocrinological aspects of low natural fertility in highland New Guinea

The Gainj of highland Papua New Guinea do not use contraception but have a total fertility rate of only 4.3 live births/woman, 1 of the lowest ever recorded in a natural fertility setting. Reproductive and marital histories were obtained from 305 females and 206 males aged 10+. Each subject was asked about: number of live born offspring ever produced; number of stillbirths ever produced; number and names of offspring currently being nursed; number of current and past spouses; and the cause of dissolution of all past marriages. Blood samples were drawn from 172 volunteer female subjects aged 10-60 years and ovarian function was classified by concentration of progesterone. From an analysis of these cross-sectional demographic and endocrinological data, the causes of low reproductive output have been identified in women of this population as: late menarche and marriage, a long interval between marriage and 1st birth, a high probability of widowhood at later reproductive ages, low effective fecundability and prolonged lactational amenorrhea. These are combined with near-universal marriage, and a low prevalence of primary sterility similar to that found in other populations. Of all the factors limiting fertility, by far the most important are those involved in birth spacing, especially lactational amenorrhea. The effects of widowhood on Gainj fertility are negligible. Factors acting to lower fertility fall into 2 categories: those that determine the age of onset of reproduction and those that act to space births. Given the observed pattern of birth spacing, however, the delay in commencement of reproduction represents on average no more than 1 or 2 live births averted/woman. In contrast, were age at 1st reproduction held constant while reducing birth intervals to a mean of 2.0-2.5 years, total fertility would increase to about 7 or 8. Future research on natural fertility should focus on specific behavioral and physiological mechanisms governing the reproductive process.

Female fecundity in highland Papua New Guinea

Demographers often assume that interpopulation variation in birth spacing is attributable primarily to behavioral differences (e.g., in breastfeeding, coital frequency, or contraceptive practice), and that the contribution of physiological factors is negligible. This assumption may be correct, but it should be tested, especially in light of recent evidence that there may be more variation in ovarian function among human populations than was previously believed. In this paper, we apply a stochastic model of the determinants of fecundability (the monthly probability of conception) to endocrinological data collected among the Gainj, a tribal population in highland Papua New Guinea. Based on previous research, the Gainj are known to have age patterns of ovarian function that differ markedly from the Western norms. When account is taken of the late menarche, early menopause, and long ovarian cycles that appear to characterize Gainj women, mean apparent fecundability across the female reproductive span is reduced by about 27 per cent (from 0.316 to 0.235), and the mean waiting time to next apparent conception is increased by just over one month. Thus, despite the fact that Gainj women differ from Western women with respect to reproductive physiology by as much as or more than any other known population, the demographic impact of these differences appears to be slight.

Women and development: a highland New Guinea example

This paper presents an analysis of household variables and their relationship to success in cash cropping among the Gainj of Madang Province, Papua New Guinea. Censuses and household surveys from 1978, the year in which cash cropping began, and 1983 provide data that show different patterns of change in household structure for more and less commercially successful households. The results illustrate the importance of womens labor in economic development and the dynamic nature of the relationship between household structure and economic development.

Infant Mortality and Intra-Household Competition in the Northern Islands of Orkney, Scotland, 1855-2001

This study applies principles from the theory of household life cycles to the study of early childhood mortality in the population of the Northern Orkney Islands, Scotland. The primary hypothesis is that unfavorable household economic conditions resulting from changes in household demographic composition increase the risk of death for children under the age of 5 years because of limited resources and intra-household competition. We apply Cox proportional hazards models to nearly 5,000 linked birth and death records from the Northern Orkney Islands, Scotland, from the period 1855 to 2001. The dependent variable is the childs risk of death before age 5. Findings suggest that children in households with unfavorable age compositions face higher risk of death. This elevated risk of death continues once heterogeneity among children, islands, and households is controlled. Results also show differential risk of death for male children, children of higher birth orders, and twin births. The analyses present evidence for intra-household competition in this historic setting. The most convincing evidence of competition is found in the effects of household consumer/producer ratios and twinning on child mortality risks.

Changing household composition, labor patterns, and fertility in a highland New Guinea population

The European demographic transition of the nineteenth century is often proposed as a model for demographic change in twentieth century developing nations, and economic development is seen as leading to an inevitable reduction in total fertility in these nations. This paper examines data from the Gainj of Papua New Guinea, a natural fertility population with very low reproductive output, and suggests that the effects of development on fertility change are much more complex than a simple demographic transition model would suggest. Looking at two variables known to contribute significantly to low total fertility among the Gainj, late age at first birth for women and long interbirth intervals, the paper suggests that households, in their recruitment and allocation of labor, may exert a mediating influence in the relationship between economic development and fertility.

Empirical Approaches to Household Organization

This issue of Human Ecologyis devoted to studies of household organization, originally presented at an invited session of the American Anthropological Association annual meetings in New Orleans in 1990. These papers share an empirical orientation and an interest in demographic processes and economic change, particularly in rural and non-Western societies, including !Kung foragers and Herero agro-pastoralists of Botswana, Ariaal and Rendille pastoralists of Kenya, Gainj horticulturalists of highland New Guinea, and a Euro-Caribbean populaiton of St. Barthélemy, West Indies. These papers demonstrate both the vitality of household studies and the utility of empirical approaches in understanding household formation, continuity, and adaptation to social, economic, and political change.

Every Good Marriage Begins with Tears

This film by Simon Chambers captures much of the social and cultural conflict and confusion entailed in being both Bangladeshi and British, as it chronicles the difficulties of arranged marriages for two sisters. Born and reared in London, Shahanara and her younger sister Hushnara are the daughters of traditional parents who are attempting to assure their proper marriages to Bangladeshi husbands. Indeed Shahanara has already gone though a wedding in Bangladesh six months before appearing in the film, which begins on the day of her husband’s arrival in London. On the same flight is her sister, who is for the first time to meet Rashed, the London-based husband her parents have chosen for her after consultation with his parents during a trip to Bangladesh. Shahanara talks about the reasons she married Mamun and her understanding of why he married her. Having been evicted and abandoned by her father five years earlier because of her refusal to conform to Bangladeshi social standards for young women, she sees her marriage as a way back into the family, and especially as a way to re-establish a relationship with her mother. She is suspicious of Mamun’s claim that he loves her, and assumes that he has married her because she has a British passport which will allow him legal entry into the United Kingdom. She is willing to give the marriage a chance, but makes it clear that if it doesn’t work she will end it. Although Hushnara’s vacillation about her impending marriage and her eventual wedding ceremony occupymuch of the film, the focus is clearly on Shahanara, whose intelligence, humor, openness, profanity and volubility make her an extremely attractive protagonist to non-Bangladeshi viewers. Although questioning her new husband’s commitment to her rather than to her passport, she agrees to ‘‘give it a try,‘‘ and expresses compassion for Mamun because he has left his family behind in Bangladesh. During their first few hours together she displays a somewhat teasing affection despite his reprimanding her about her profanity. Two months later she has left her husband and is living with an older married Visual Anthropology, 25: 228–230, 2012 Copyright # Taylor & Francis Group, LLC ISSN: 0894-9468 print=1545-5920 online DOI: 10.1080/08949468.2012.629595