Hostname: page-component-848d4c4894-wg55d Total loading time: 0 Render date: 2024-06-01T18:38:35.576Z Has data issue: false hasContentIssue false

Triplets and Higher Order Multiple Births in Japan

Published online by Cambridge University Press:  01 August 2014

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

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Multiple birth rates in entire Japan were analyzed using vital statistics for 1951 to 1988. The triplet rate was nearly constant from 1951 to 1974, where the rate per million births was 58, then increased with the year up to 1982 (104), and decreased up to 1984, and suddenly increased thereafter (109 in 1987). The average rate of quadruplets per million births from 1951 to 1968 was 0.93, then increased with the year up to 1975 (7.5), and decreased until 1984 and suddenly increased thereafter (10.6 in 1987). The rate of quintuplets was 0.77 per million births during the period from 1975 to 1987. The higher multiple birth rate since 1975 was attributed to the higher proportion of mothers treated with ovulation-inducing hormones in Japan. Since 1985, higher multiple birth rates might be partially attributed to in vitro fertilization. The stillbirth rates for male triplets gradually decreased from 1960 to 1978 and thereafter remained constant at a little higher level except in 1988, whereas the rates for females gradually decreased with the year. The overall stillbirth rates decreased to 1/4 for triplets and to 1/5 for quadruplets during the 37-year period from 1951. The overall stillbirth rate of quintuplets was 0.60 (51/85) during the period 1975-1987.

Type
Research Article
Copyright
Copyright © The International Society for Twin Studies 1990

References

REFERENCES

1.Allen, G (1960): A differential method for estimation of type frequencies in triplets and quadruplets. Am J Hum Genet 12:210224.Google Scholar
2.Allen, G (1988): Frequency of triplets and triplet zygosity types among U.S. births, 1964. Acta Genet Med Gemellol 37:299306.Google ScholarPubMed
3.Baba, K (1978): Quintuplet births in the world (in Japanese). Nihon Taishitsugaku Zashi 43:863869.Google Scholar
4.Brackenridge, CJ (1978): Aspects of the increasing triplet rate in Australia. J Biosoc Sci 10:183188.CrossRefGoogle ScholarPubMed
5.Buhner, MG (1970): The Biology of Twinning in Man. Oxford: Clarendon Press.Google Scholar
6.Imaizumi, Y (1987): The recent trends in multiple births and stillbirth rates in Japan. Acta Genet Med Gemellol 36:325334.Google ScholarPubMed
7.Imaizumi, Y (1989): Stillbirth rate and weight at birth of quintuplets in Japan. Acta Genet Med Gemellol 38:6569.Google ScholarPubMed
8.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 28:107124.Google Scholar
9.Imaizumi, Y, Asaka, A, Inouye, E (1980): Analysis of multiple birth rates in Japan. II. Secular trend and effect of birth order, maternal age, and gestational age in stillbirth rate of twins. Acta Genet Med Gemellol 29: 223231.Google Scholar
10.Imaizumi, Y, Inouye, E (1980): Analysis of multiple birth rates in Japan. III. Secular trend, maternal age effect, and geographical variation in triplet rates. Jpn J Hum Genet 25:7381.Google Scholar
11.Imaizumi, Y, Inouye, E (1980): Analysis of multiple birth rates in Japan. IV. Secular trend, effect of maternal age and gestational age in stillbirth rates of triplets. Jpn J Hum Genet 25:219227.Google Scholar
12.Imaizumi, Y, Inouye, E (1982): Analysis of multiple birth rates in Japan. VI. Quadruplets: Birth and stillbirth rates. Jpn J Hum Genet 27:227234.Google Scholar
13.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 1974–1988.Google Scholar
14.Japan, Ministry of Health and Welfare: Survey on Socio-Economic Aspects of Vital Events - Plural Births in 1975. Health and Welfare Statistics and Information Department, Ministry of Health and Welfare, Tokyo, 1977.Google Scholar
15.Mori, T (1987): Progress in reproductive and medical technology (in Japanese). Sanfujinkano Sekai 39:963966.Google Scholar
16.Sawazaki, C, Tsubata, H (1976): Statistics of multiple births in Japan (in Japanese). Sanka to Fujinka 43:863869.Google Scholar