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MATERNAL AND ENVIRONMENTAL FACTORS AFFECTING TWIN BIRTHS IN CANADIAN CITIES
Article first published online: 23 AUG 2005
DOI: 10.1111/j.1471-0528.1978.tb14893.x
Issue
1471-0528/asset/cover.gif?v=1&s=b4e1d96c46e18c61210d584b63c13ee375cf562b "BJOG: An International Journal of Obstetrics & Gynaecology")
BJOG: An International Journal of Obstetrics & Gynaecology
Volume 85, Issue 5, pages 351–358, May 1978
Additional Information
How to Cite
Elwood, J. M. (1978), MATERNAL AND ENVIRONMENTAL FACTORS AFFECTING TWIN BIRTHS IN CANADIAN CITIES. BJOG: An International Journal of Obstetrics & Gynaecology, 85: 351–358. doi: 10.1111/j.1471-0528.1978.tb14893.x
Publication History
- Issue published online: 23 AUG 2005
- Article first published online: 23 AUG 2005
- Abstract
- References
- Cited By
Summary
Details of 4972 pairs of twins born to mothers resident in 14 large Canadian cities in the years 1952, 1957, 1962, and 1967 were compared to those of a random sample of 4969 single births. Both dizygotic and monozygotic twinning rates, derived by Weinberg's formula, showed increases with both maternal age and with the number of previous livebirths. Dizygotic twinning rates also showed a seasonal variation with an October maximum. Twinning rates were lower in Oriental women, but did not vary between other ethnic groups, or by city of residence, legitimacy, paternal age or maternal history of stillbirths.
The data were kindly supplied by Mr N. Tompkins and the staff of Statistics Canada, and computer programming was performed by Mr K. Johnson.