| Project/Area Number |
60480183
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Hygiene
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| Research Institution | Teikyo University School of Medicine |
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Principal Investigator |
MIURA Teiji Teikyo University School of Medicine, 医学部, 教授 (90082073)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1986: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1985: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | Twins; Season / Season of Birth / Maternal Factor / Ultrasonic Tomography / Threatened Abortion / 切迫流産 / 卵性 / 疫学 |
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| Research Abstract |
(1) The clinical records of 73,339 maternities (1924-1980) in one hospital in Tokyo and questionnaires to 1,434 mothers of twins were investigated. The twinning rate was higher, in general, in summer or fall but this seasonal variation changed every 2-4 years period during 1971-1984. Years when twinning rate was higher in the summer-fall season and those when a peak of the rate was not observed appeared alternately. The seasonality of birth was different between the mothers of like- and unlike-sexed twins. The mothers of unlike-sexed twins were born more frequently in March-April.
(2) Among 1049 case records (1981-1982) of another hospital in Tokyo, 59 cases complicated with threatened abortion before 10 gestational week were examined. The pregnancies which terminated in February-May were more frequently complicated with threatened abortion before 10 gestational week and the twins were born more frequently in February-July. The mothers born in May-August were complicated with threatened abortion more frequently and the mothers born in August-October delivered twins more frequently.
(3) We observed 57 cases with echo-free-space (EFS) by the ultrasonographic examination of 215 pregnant women in the early gestational stage in three hospitals (1985-1987). Among the 57 cases with EFS images, seven cases had the images similar to the gestatinal sac and one of them was suspected of having ultrasound evidence for so-called a "vanishing twin." Among women without EFS images, three sets of viable twins were involved. Both cases with EFS images and cases with viable twins were frequently found in fall-winter and both cases were born more frequently in winter-spring.
(4) The existence of some epidemic twin proneness factors and its relation to some abortion proneness factors was discussed.
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