Demographic variables in fetal and child mortality: Hmong in Thailand.

Conventional theories would not predict the 60% decline of infant mortality which has occurred among the Hmong population of Thailand, from 123/1000 in the mid-1960s to 48 in the mid-1980s. The Hmong population in northern Thailand has sustained high fertility and low use of modern health services. Most Hmong live in relatively remote rural villages and earn their living by self-employed farming. They have low levels of education, especially for women. They live in multi-generational patrilineal-patrilocal extended family households. Women's status is low. These characteristics contrast strongly with the majority ethnic Thai population, among whom a comparable mortality decline has been accompanied by widespread use of family planning, rapidly declining fertility, widespread use of modern health facilities, rapidly increasing levels of education for both sexes, rapid economic development, and a predominance of nuclear-based family households. Distributions of Hmong pregnancies by birth order and maternal age have remained relatively constant while fetal and young child death rates have declined for each level of parity and all maternal ages in recent cohorts. As predicted by conventional theories, infant mortality rates are highest among higher order births and for births to mothers of the highest ages, however there is relatively little effect on risk of infant mortality of first order pregnancies, or births to very young (10-14 year old) women. Fetal and infant mortality have declined steadily in recent cohorts at each parity level and all maternal ages. Modern medical care and decline in a surplus of female deaths associated with low status of women might explain the declines in fetal and child deaths regardless of parity or maternal age. Use of modern medical care for delivery is recent and accounts for less than 10% of all recent Hmong births, but survival rates are not consistently or significantly higher for children born with a modern birth attendant. Sex-specific mortality rates calculated from reproductive histories show no surplus of female deaths in the past, but females have benefitted more from recent mortality declines than males. Ethnographic evidence suggests that Hmong have customs which act to protect the health of mother and child ('chicken soup theory'), and that they are predisposed to accept innovations (including use of modern medicine) which they see as beneficial. This may allow them to respond especially quickly to small opportunities for improving their children's survival, as compared with other ethnic groups.