Hostname: page-component-78c5997874-lj6df Total loading time: 0 Render date: 2024-11-17T17:54:47.144Z Has data issue: false hasContentIssue false
  • English
  • Français

Secular changes in dizygotic twinning rates

Published online by Cambridge University Press:  31 July 2008

William H. James
William H. James
Affiliation:
Gallon Laboratory, University College London
Get access Rights & Permissions [Opens in a new window]

Extract

In Australia, Belgium, Denmark, England and Wales, Holland, Italy, New Zealand, Norway, Scotland, Sweden and Switzerland there was a substantial decline in dizygotic twinning rates during the 1960s. In Portugal, Spain and Japan there was a lesser decline and in the US there was little change. In many of the countries for which evidence is available, it seems that these declines all started at about the same time in the late 1950s. It has been suggested that the recent decline in Scotland occurred mainly in middle class women; in contrast it is suggested here that the earlier decline in the US during the years 1933–58 was more characteristic of lower class women. For England and Wales and for Scotland, the recent decline (unlike that in the US 1933–58) occurred about equally in young and older women, so that the causes of the declines in the US in 1933–58 and in other countries at present may be different. In the absence of hard evidence, it is speculated that the current declines may be due to hormonal or pesticidal substances widely used in agriculture.

Monozygotic twinning rates have shown no similar trend so that pregnancy wastage does not seem to be implicated.

Type
Research Article
Information
Journal of Biosocial Science , Volume 4 , Issue 4 , October 1972 , pp. 427 - 434
Copyright
Copyright © 1972, Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Allen, G. & Schachter, J. (1970) Do conception delays explain some changes in twinning rates? Acta Genet. med. Gemell. 19, 30.CrossRefGoogle ScholarPubMed
Allen, G. & Schachter, J. (1971) Ease of conception in mothers of twins. Social Biol. 18, 18.CrossRefGoogle ScholarPubMed
Bureau of the Census in the US Department of Commerce. The US Book of Facts, Statistics and Information for 1969. Essandess, New York.Google Scholar
Czeizel, A. & Acsadi, G. (1971) Demographic characteristics of multiple births in Hungary. Acta Genet. med. Gemell. 20, 301.CrossRefGoogle Scholar
Grabill, W.H., Kiser, C.V. & Whelpton, P.K. (1958) The Fertility of American Women. Census Monograph Series. Wiley, New York.Google Scholar
Heuser, R.L. (1967) Multiple Births, US 1964. National Center for Health Statistics, P.H.S. Publication No. 1000, Series 24, No. 14. Washington, D.C.Google Scholar
Jeanneret, O. & MacMahon, B. (1962) Secular changes in rates of multiple births in the U.S. Am. J. hum. Genet. 14, 410.Google Scholar
Kiser, C.V. (1970) Changing patterns of fertility in the US. Social Biol. 17, 302.CrossRefGoogle Scholar
MacGillivray, I. (1970) The changing incidence of twinning in Scotland 1939–68. Acta Genet. med. Gemell. 19, 26.CrossRefGoogle Scholar
Parkes, A.S. (1969) Multiple births in man. J. Reprod. Fert. Suppl. 6, 105.Google Scholar
Registrar General of England & Wales. Statistical Review for 1966, Commentary. HM Stationery Office, London.Google Scholar
Westoff, C.F. (1954) Differential fertility in the US 1900–52. Am. Sociol. Rev. 19, 549.CrossRefGoogle Scholar
Wyshak, G. & White, C. (1969) Fertility of twins and parents of twins. Hum. Biol. 41, 66.Google ScholarPubMed