1993 Fiscal Year Final Research Report Summary
Direct measurement of Recent Hutterite Fertility
| Project/Area Number |
04670316
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Hygiene
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| Research Institution | Teikyo University School of Medicine |
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Principal Investigator |
NONAKA Koichi Teikyo Univ.School of Medicine, Department of hygiene, Lecturer, 医学部, 講師 (80142446)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Hutterites / Fertile population / Natural fertility / Twinning / Seasonal variation / Birth interval / Maternal age / Popoulation database |
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| Research Abstract |
The main purpose of this study was to confirm an estimated recent decline in the fertility of the Hutterites, using a firsthand source of data. The church book that has been kept by a preacher of the Dariusleut sect of the Hutterites enabled us to construct a computerized database on their vital events such as births, marriages, baptisms and deaths. Data in the database has been returned to the Hutterites for their benefit. The recent decline in Hutterite fertility was verified in the present study : the age-specific fertility rate reduced by 36% on average from the 1951-1955 to 1981-1985. The reduction was most evident at higher maternal age, especially at 30 years of age and older. Probability of having a live birth at a given age, however, still peaked at around the age of 20 years, which suggests that the fecundity of recent Hutterite women has not been changed despite the apparent fertility decline. A separate cohort analysis on the database revealed that the reduced number of children born to a recent woman was not fully explained by a factor of the observed delay in the age at marriage. The database also provided us with the information of the twinning rate. The rate fluctuated by year period as well as by season : May-July was a season of a low twinning rate, but only in the period before 1965. Environmental factors are supposed to have been involved in the etiology of twinning, probably through the incidence of dizygotic twins. Twin births were accompanied with a prolonged preceding birth interval, especially at the ages of 30-34 years, which suggested the occurrence of twinning at a relatively younger maternal age may indicate a lower, not higher, fecundity of women. Several biological aspects of human reproduction under a contraception-free condition have been and will be clarified from this database.
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Research Products
(6 results)
