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The ecology of birth seasonality among agriculturalists in central Africa

  • Robert C. Bailey (a1), Mark R. Jenike (a1), Peter T. Ellison (a2), Gillian R. Bentley (a3), Alisa M. Harrigan (a2) (a4) and Nadine R. Peacock (a1)...

The Lese are subsistence farmers living in the Ituri Forest of north-east Zaïre. They exhibit significant birth seasonality, with lowest frequencies of conception when food production is least, nutritional status is low and ovarian function, as measured by salivary steroid hormone levels, is reduced. Efe pygmy foragers, who live in the same geographical area but are less dependent on cultivated foods and have a more flexible life style, do not exhibit frequent fluctuations in nutritional status nor significant birth seasonality. These findings support a model of birth seasonality relating climatic variables to variation in fertility through a causal chain linking rainfall to food production to energy balance to ovarian function to fertility. The model, which emphasises an ecological approach to the study of human reproduction, should have broad applicability since seasonality of food production and energy balance is widespread geographically and across a wide variety of economies and cultures.

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O. Ayeni (1986) Seasonal variation in births in rural southwestern Nigeria. Int. J. Epidemiol. 15, 91.

R. C. Bailey & I. Devore (1989) Research on the Efe and Lese populations of the Ituri Forest, Zaïre. Am. J. phys. Anthropol. 78, 459.

I. Z. Beitins , J. W. McArthur , B. A. Turnbull , G. S. Skrinar & B. A. Bullen (1991) Exercise induces two types of hormone luteal dysfunction: confirmation by urinary free progesterone. J. clin. Endocr. Metab. 72, 1350.

B. A. Bullen , G. S. Skrinar , I. Z. Beitins , G. Vonmering , B. A. Turnbull & J. W. McArthur (1985) Induction of menstrual disorders by strenuous exercise in untrained women. New Engl. J. Med. 312, 1349.

L. C. Chen , S. Ahmed , M. Gesche & W. H. Mosley (1974) A prospective study of birth interval dynamics in rural Bangladesh. Popul. Stud. 28, 277.

S. J. Clark & R. W. Thompson (1987) Seasonal distribution of live births in a rural community in the southern United States. Hum. Ecol. 15, 289.

R. G. Condon & R. Scaglion (1982) The ecology of human birth seasonality. Hum. Ecol. 10, 495.

U. M. Cowgill (1966) Season of birth in man. Contemporary situation with special reference to Europe and the southerh hemisphere. Ecology, 47, 614.

K. Davis & J. Blake (1956) Social structure and fertility: an analytic framework. Econ. Dev. cult. Change, 4, 211.

P. T. Ellison (1990) Ovarian function and reproductive ecology: new hypotheses. Am. Anthrop. 92, 933.

P. T. Ellison (1991) Reproductive ecology and human fertility. In: Applications of Biological Anthropology to Human Affairs. Edited by G. W. Lasker & C. G. N. Mascie-Taylor . Cambridge University Press, Cambridge.

P. T. Ellison , N. R. Peacock & C. Lager (1989) Ecology and ovarian function among Lese women in the Ituri Forest, Zaïre. Am. J. phys. Anthropol. 78, 519.

O. Frank (1983) Infertility in sub-Saharan Africa: estimates and implications. Popul. Dev. Rev. 9, 137.

J. A. Hart & T. B. Hart (1986) Ecological basis of hunter-gatherer subsistence in African rainforest: the Mbuti case of Zaïre. Hum. Ecol. 14, 29.

L. Henry (1961) Some data on natural fertility. Eugen. Q. 8, 81.

S. A. Hill (1888) The life statistics of an Indian province. Nature, Lond. 38, 245.

A. M. Hurtado & K. R. Hill (1990) Seasonality in a foraging society: variation in diet, work effort, fertility, and sexual division of labor among the Hiwi of Venezuela. J. anthropol. Res. 46, 293.

W. H. James (1971) Social class and season of birth. J. biosoc. Sci. 3, 309.

W. H. James (1990) Seasonal variation in human births. J. biosoc. Sci. 22, 113.

C. Lager & P. T. Ellison (1990) Effect of moderate weight loss on ovarian function assessed by salivary progesterone measurements. Am. J. hum. Biol. 2, 303.

P. W. Leslie & P. H. Fry (1989) Extreme seasonality of births among nomadic Turkana pastoralists. Am. J. phys. Anthropol. 79, 103.

R. J. Levine , B. L. Bordson , R. M. Mathew , M. H. Brown , J. M. Stanley & T. B. Starr (1988) Deterioration of semen quality during summer in New Orleans. Fert. Steril. 49, 900.

C. D. Mathers & R. S. Harris (1983) Seasonal distribution of births in Australia. Int. J. Epidemiol. 12, 326.

R. L. McDonald (1966) Lunar and seasonal variations in obstetric factors. J. Genet. Psychol. 108, 81.

T. Miura (1987) The influence of seasonal atmospheric factors on human reproduction. Experientia, 43, 48.

S. W. Mosher (1979) Birth seasonality among peasant cultivators: the interrelationship of workload, diet, and fertility. Hum. Ecol. 7, 151.

E. Nurge (1970) Birth rate and work load. Am. Anthrop. 72, 1434.

B. Pasamanick , S. Dinitz & H. Knobloch (1959) Geographic and seasonal variations in birth rates. Publ. Hlth Rep. 74, 285.

B. Pasternak (1978) Seasons of birth and marriage in two Chinese localities. Hum. Ecol. 6, 299.

R. W. Thompson & M. C. Robbins (1973) Seasonal variation in conception in rural Uganda and Mexico. Am. Anthrop. 75, 676.

J. R. Udry & N. M. Morris (1967) Seasonality of coitus and seasonality of birth. Demography, 4, 673.

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Journal of Biosocial Science
  • ISSN: 0021-9320
  • EISSN: 1469-7599
  • URL: /core/journals/journal-of-biosocial-science
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