Frequency of Twinning in California1

Shipley, Paul W.; Wray, Jo Ann; Hechter, H. H.; Arellano, Max G.; Borhani, Nemat O.

doi:10.1093/oxfordjournals.aje.a120671

Cited by 40 publications

(9 citation statements)

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“…Among Whites there were 259 twin births in 25 991 pregnancies (1 : 100.3 births); among Negroes, 331 in 26 080 (1 : 78.8 births); and among the Other group, consisting mostly of Puerto Ricans, 25 in 4178 (1 : 167.1 births). The twin birth incidence was higher among Negroes than among Whites, and agrees with previous findings (Strandskov, 1945;Enders and Stern, 1948;Shipley et al, 1967; US Dept. of HEW, 1967).…”

supporting

confidence: 92%

A Survey of Twins in the Population of a Prospective Collaborative Study

Myrianthopoulos

1970

Acta genet. med. gemellol.

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This report is concerned with the twin births which occurred in the Collaborative Study of Cerebral Palsy, Mental Retardation and Other Neurological and Sensory Disorders of Infancy and Childhood. This is a collaborative endeavor of 14 institutions throughout the US and the National Institute of Neurological Diseases and Stroke, to observe and study factors which affect the parents before a child is born and to relate them to the outcome of pregnancy. To this end, we are following approximately 60 000 pregnant women from the first months of their pregnancy, through labor and delivery and up to the seventh year of the study child's life. The Study population is about 46% White, 46% Negro, 7% Puerto Rican, and the rest a variety of other ethnic groups. The prospective nature of the study makes possible the recording of observations with high accuracy and the avoidance of biases inherent in other types of investigations. These advantages should also be reflected in the collection and evaluation of twin data.

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supporting

confidence: 92%

A Survey of Twins in the Population of a Prospective Collaborative Study

Myrianthopoulos

1970

Acta genet. med. gemellol.

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“…The decline of twinning rates during this century, due to a fall of DZ rates, has been observed in many countries [2,7,9,10,13,16,17,20,23,28,31]. Significant racial differences in DZ, more than MZ rates were reported by some investigators [20,23,24,29,31]. An increase of twinning rates by maternal age and parity was also frequently found [1,3-5, 7-13,16,20-23,28-29].…”

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confidence: 96%

Epidemiological Characteristics of Twinning Rates in Taiwan

Chen

Lin

Chang

et al. 1987

Acta genet. med. gemellol.: twin res.

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Delivery records of public hospitals and birth certificates of household registration offices were examined to study the epidemiological characteristics of twinning rate from 1955 to 1984 in Taiwan. The MZ twinning rate was consistently higer than the DZ rate during the study period. The DZ rate declined steadily from 2.7 per 1000 in 1955 to 1.3 per 1000 in 1975, and then gradually increased to 3.6 per 1000 in 1984. The MZ rate peaked periodically in 1956, 1966 and 1976, and gradually increased from 3.3 per 1000 in 1978 to 5.9 per 1000 in 1986. Both MZ and DZ rates were higher in urban than in rural areas and they were also higher in northern Taiwan than elsewhere in the island. While both MZ and DZ rates increased with maternal age and parity, the maternal age difference and the parity difference were more striking in DZ than in MZ rates. The international comparison also showed a greater racial difference in maternal age-specific DZ than MZ twinning rates; and the older the maternal age, the greater the international discrepancy in DZ rates.

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“…THE incidence of multiple pregnancy is high in West Africa and the highest twinning rate on record (approximately 50 per lo00 maternities) is found among the Yorubas in Western Nigeria (Nylander, 1967 and, an incidence over four times that in the Caucasian populations of the U.S.A. and U.K. The Negro population in the U.S.A. also has a higher multiple pregnancy rate than the Caucasian population (Shipley et al, 1967). Differences in twinning are due to variation in dizygotic twinning rates as the incidence of monozygotic twinning is fairly constant in all populations (Bulmer, 1960;Nylander, 1969).…”

mentioning

confidence: 99%

Serum Levels of Gonadotrophins in Relation to Multiple Pregnancy in Nigeria

Nylander

1973

BJOG

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Summary Serum levels of follicle stimulating hormone (FSH) and luteinizing hormone (LH) were measured daily for 10 days from the 7th day of the menstrual cycle in 15 healthy Yoruba women, six of whom had singleton infants, seven of whom had had one set of twins, and two of whom had had two sets of twins. Mean FSH levels were higher at the peak and for four days before and after the peak in women who had had twins, compared to those who had had singletons, and higher still in the women who had had two sets of twins. Mean LH levels and the height of the LH peak were less clearly related to the twinning history.

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Frequency of Twinning in California1

Cited by 40 publications

References 0 publications

A Survey of Twins in the Population of a Prospective Collaborative Study

A Survey of Twins in the Population of a Prospective Collaborative Study

Epidemiological Characteristics of Twinning Rates in Taiwan

Serum Levels of Gonadotrophins in Relation to Multiple Pregnancy in Nigeria

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