MATERNAL AND ENVIRONMENTAL FACTORS AFFECTING TWIN BIRTHS IN CANADIAN CITIES
- 1 May 1978
- journal article
- Published by Wiley in BJOG: An International Journal of Obstetrics and Gynaecology
- Vol. 85 (5) , 351-358
- https://doi.org/10.1111/j.1471-0528.1978.tb14893.x
Abstract
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.Keywords
This publication has 10 references indexed in Scilit:
- TWINNING RATES AMONG WOMEN AT THE END OF THEIR REPRODUCTIVE SPAN AND THEIR RELATION TO AGE AT MENOPAUSEAmerican Journal of Epidemiology, 1975
- Secular changes in dizygotic twinning ratesJournal of Biosocial Science, 1972
- Seasonal Variation in Twin BirthsNature, 1972
- Excess of Like Sexed Pairs of Dizygotic TwinsNature, 1971
- The Inheritance of DZ Twinning A study of 18737 maternities in Ibadan, Western NigeriaActa geneticae medicae et gemellologiae, 1970
- Chi-Square Tests with One Degree of Freedom; Extensions of the Mantel- Haenszel ProcedureJournal of the American Statistical Association, 1963
- TWINNING IN YORUBA WOMENBJOG: An International Journal of Obstetrics and Gynaecology, 1960
- Changes in twin frequenciesActa geneticae medicae et gemellologiae, 1954
- Season and Rate of ConceptionNature, 1938
- Beiträge zur Physiologie und Pathologie der Mehrlingsgeburten beim MenschenPflügers Archiv - European Journal of Physiology, 1901