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Twinning Rates in Japan, 1951-1990

Published online by Cambridge University Press:  01 August 2014

Y. Imaizumi
Y. Imaizumi*
Affiliation:
Institute of Population Problems, Ministry of Health and Welfare, Tokyo, Japan
*
Ministry of Health and Welfare, Kasumigaseki, Chiyoda-ku, Tokyo, Japan

Abstract

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Twinning rates in all of Japan for 1951-1968 and 1974-1990 were analyzed using data from vital statistics of Japan. The twinning rate per 1,000 births was 6.43 in 1951 and remained nearly constant until 1968, then decreased to 5.79 in 1974 and gradually increased to 7.00 in 1990. The MZ twinning rate increased slightly up to 1966, but decreased thereafter, whereas the DZ rate declined over the entire period. As for maternal age, the DZ rate increased up to the age group 35-39 and decreased thereafter. The same tendency is seen in the MZ rate, but the maternal age effect is less marked than in DZ twins. The same tendency is also seen in the overall rate for 1975-1985. As for geographical variations, the MZ and DZ rates were computed in each prefecture for 1955-1959 and in 1974. The DZ rate increased from a low level in the southwest of Japan to a high level in the northeast for both periods, whereas the MZ rate was rather constant in 1974 throughout Japan. As for seasonal variation, the highest rates per 1,000 births for MZ(4.56) and DZ(2.20) twins were seen in April, with the lowest rate in September (3.69) for MZ twins and in July (1.71) for DZ twins.

Keywords

Twinning ratesMaternal ageBirth orderInduced ovulation
Type
Research Article
Information
Acta geneticae medicae et gemellologiae: twin research , Volume 41 , Issue 2-3 , July 1992 , pp. 165 - 175
Copyright
Copyright © The International Society for Twin Studies 1992

References

REFERENCES

1. Bulmer, MG (1960): The twinning rate in Europe and Africa. Ann Hum Genet 24:121–125.Google Scholar
2. Chen, CJ, Lin, TM, Chang, YJ (1987): Epidemiological characteristics of twinning rates in Taiwan. Acta Genet Med Gemellol 36:335–342.Google Scholar
3. Elwood, JM (1978): Maternal and environmental factors affecting twin births in Canadian cities. Br J Obst Gynaecol 85:351–358.Google Scholar
4. Imaizumi, Y, Inouye, E (1979): Analysis of multiple birth rates in Japan. I. Secular trend, maternal age effect, and geographical variation in twinning rates. Acta Genet Med Gemellol 28:107–124.Google Scholar
5. Imaizumi, Y, Inouye, E (1980): Analysis of multiple birth rates in Japan. V. Seasonal and social class variations in twin births. Jpn J Hum Genet 25:299–307.Google Scholar
6. Imaizumi, Y (1992): The rising number of multiple pregnancies in Japan and other nations. In Fertility, Sterility and Contraception, UK: Parthenon Publishing.Google Scholar
7. Inouye, E (1957): Frequency of multiple births in three cities of Japan. Am J Hum Genet 9:317–320.Google Scholar
8. Inouye, E, Imaizumi, Y (1981): Analysis of twinning rates in Japan. Twin Research 3: Twin Biology and Multiple Pregnancy. New York: Alan R. Liss, pp 21–33.Google Scholar
9. Japan, Ministry of Health and Welfare: Vital Statistics. Health and Welfare Statistics and Information Department, Ministry of Health and Welfare, Tokyo. Annual. 1951-1968 and 1974-1990.Google Scholar
10. Kamimura, K (1976): Epidemiology of twin births from a climatic point of view. Br J Prev Social Med 30:175–176.Google ScholarPubMed
11. Kang, YS, Cho, WK (1960): On the twin births of the Korean population. J Nat Acad Sciences 2:90–101.Google Scholar
12. Kim, HJ, Kim, WS, Lee, CH, Rha, DJ, Lee, JK, Kim, SP (1988): Statistical analysis of twin pregnancy for 10 years (1975-1984). Korean J Obstet Gynecol 31:1544–1551.Google Scholar
13. Komai, T, Fukuoka, G (1936): Frequency of multiple births among the Japanese and related peoples. Am J Phys Anthropol 21:433–447.Google Scholar
14. Milham, S Jr (1964): Pituitary gonadotropin and dizygotic twinning. Lancet 2:556.Google Scholar
15. Morton, NE, Chung, CS, Mi, MP (1967): Genetics of Inter-Racial Crosses in Hawaii. Monographs in Human Genetics 3. Basel: Karger.Google Scholar
16. Nylander, PPS (1973): Serum levels of gonadotrophins in relation to multiple pregnancy in Nigeria. J Obstet Gynaecol 80:651–653.Google ScholarPubMed
17. Shipley, PW, Wray, JR, Hechter, HH, Arellano, MG, Borhani, NO (1967): Frequency of twinning in California: Its relationship to maternal age, parity and race. Am J Epidemiol 85: 147–156.Google Scholar
18. Soma, H, Takayama, M, Kiyokawa, T, Akaeda, T, Tokoro, K (1975): Serum gonadotropin levels in Japanese women. Obstet Gynecol 46:311–312.Google Scholar