The existence of very low rates of fertility among non-contracepting human populations has intrigued researchers in demography and reproductive ecology. Long inter-birth intervals, driven primarily by the lactational amenorrhoea associated with breast-feeding, have been shown to be important determinants of low natural fertility in several populations. Other reports have suggested that sterility brought about by sexually transmitted diseases (STDs) might also explain low fertility in some populations, especially in Africa. This report presents an analysis of 1981 Indian census data that documents low natural fertility in Ladakh, a high-altitude region of the Himalaya in north India. In Ladakh, there is evidence for low rates of marriage among women that may be attributable to the practice of polyandry, but also high rates of primary and secondary sterility within marriage, resulting in low completed parities for post-reproductive age married women. Age-specific fertility rates derived from the number of current births are also unexpectedly low. Hypotheses to explain very low fertility in Ladakh are considered from among the likely proximate determinants and evaluated using two supplementary sources of information derived from fieldwork in Ladakh in the early 1990s. The most likely explanations for low marital fertility include sterility from STDs, high rates of fetal loss, and possibly nutritional contraints on ovarian hormone status.
PIP: This study offers an explanation of low fertility among a natural fertility population in Ladakhi region, Jammu-Kashmir state, India. Ladakhi is an isolated, mountainous Himalayan high altitude region with an arid climate, low oxygen levels, and variation in temperature. Data were obtained from the 1981 Census of India, two surveys, and samples among multi- and primiparous women in 1990 and postpartum women during 1990-94. Hypotheses are examined with proximate determinant models of Bongaarts (1978) and Wood (1994). There is a long tradition of polyandry that limits women's access to marriage. In 1981, two surveys indicate that the average number of children ever born was 4.2-4.5 in Zangskar. Census findings indicate that the total marital fertility rate in the preceding year was 4.15 births/woman. Fertility was higher in Kargil district among older ever-married women and among urban Kargil women. Average marriage age was 19.6 years. Prolonged or intensive breast-feeding was not observed during fieldwork. Birth intervals averaged 2.95 years. Neonatal mortality rates averaged about 15%; infant mortality rates averaged about 19%. In 1990, records indicate that 23.5% of women had experienced at least 1 abortion or stillbirth. Rates of nulliparity among married women were high at 10%. Low fertility may be due to ecological factors that have direct effects on reproduction or are mediated through behavior, such as sexual activity or sexually transmitted diseases (STDs), especially in Leh district. The most likely reason is compromised ovarian function due to marginal nutrition or STDs.