Multiple births in Australia, 1944–63

Pollard, Gayle

doi:10.1017/s0021932000007355

Cited by 29 publications

(16 citation statements)

References 22 publications

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“…Birth order for each twin birth correlates well with the Australian study (Pollard, 1969), with multiple birth occurrence decreasing after the first year of marriage (first birth), which possibly indicates that twin births occur more often when the first child is born to a women over 30. Figure 5 shows the number of infants and twins born in the study villages over the period 1870-1940.…”

Section: Mother's Age and Birth Ordersupporting

confidence: 60%

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Comparison of Twinning Rates for Villages in Makarska Region, Croatia

Sunde

Borić

Urlić³

et al. 2013

J. Biosoc. Sci.

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A detailed database on the genealogy of the Makarska region in Croatia has been created. The twinning rate for three villages in the region (Podgora, Tučepi and Brela) were analysed over the period 1870 to 1940 and factors such as mother's age and birth order are discussed. Of the three villages, Podgora was identified as having the highest twinning rate and consequently records for Podgora were examined further to include almost 400 years of historical data (from 1621 to 1950).

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Section: Mother's Age and Birth Ordersupporting

confidence: 60%

“…Using statistics on Australian births during the period 1944-63, Pollard (1969) concluded that the proportion of multiple births increases with increasing mother's age until 37, and decreases thereafter, and that the proportion of multiple births decreases after the first year of marriage.…”

Section: Factors Affecting Twin Birthsmentioning

confidence: 99%

Comparison of Twinning Rates for Villages in Makarska Region, Croatia

Sunde

Borić

Urlić³

et al. 2013

J. Biosoc. Sci.

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“…We do not know the causes of these changes in DZ twinning rates, nor do we know much in general about the determinants of DZ twinning, except that age and ethnicity play a role (Nylander, 1983). DZ twinning has been viewed as a marker of both reproductive failures and high fecundity (Bulmer, 1959;Eriksson & Fellman, 1967;Nylander, 1975;Pollard, 1969) and the decline in DZ twinning has been interpreted as a sign of declining fecundity. Monozygotic (MZ) twinning rates tend to remain constant over time.…”

mentioning

confidence: 99%

Coffee and Smoking as Risk Factors of Twin Pregnancies: The Danish National Birth Cohort

Morales-Suárez-Varela

Bech

Christensen

et al. 2007

Twin Res Hum Genet

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Twinning rates have changed substantially over time for reasons that are only partly known. In this study we studied smoking, coffee and alcohol intake, and their possible interaction with obesity as potential determinants of twinning rates using data from the Danish National Birth Cohort between 1996 and 2002. We identified 82,985 pregnancies: 81,954 singleton and 1031 twins. For the twins we had data to classify 121 as monozygotic, 189 dizygotic (same sex), 313 dizygotic (opposite sex) but, 408 were of the same sex but with unknown zygosity. All mothers were interviewed about their prepregnancy weight and height, coffee and alcohol intake, smoking habits, and potential confounding factors at early stages of pregnancy. We identified smoking (> 10 cigarettes/day) as a possible determinant of twinning, particularly for dizygotic twinning rates (same sex) and furthermore corroborated that obesity and the mother's age are strong correlates of twinning. Others have found coffee intake to increase twinning rates but that is not seen in these data.

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“…Among the sorts of evidence he considered were the prompt postmarital conceptions [4,9] and prompt postwar conceptions [3,8] of DZ twins. He found that within the reproductive histories of women bearing DZ twins, the conception delays leading to first-born DZ twin pairs were less than those leading to first-born singletons.…”

mentioning

confidence: 99%

Dizygotic Twinning, Birth Order, Female Psychology, and Coital Rates

James¹

1982

Acta genet. med. gemellol.: twin res.

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It is well established that the dizygotic (DZ) twinning rate increases with maternal age until about age 38 and thereafter declines, and that within each maternal age category, it increases (apparently indefinitely) with parity [5]. Interpretation of this increase with parity is not immediately clear. One may formulate two hypotheses, one or both of which may be true.Hypothesis 1: Twin-prone women are more fertile than other women and therefore they form a progressively increasing proportion of the mothers at each birth rank and/or Hypothesis 2: Each birth somehow adds an increment to a woman's probability of bearing a DZ twin pair at her next pregnancy.Allen [1] tested the latter hypothesis in the following way. For a group of sibships all of the same size, and all of which contained a pair of DZ twins, he considered only those pregnancies occurring in a given limited age range, e.g., 25-29. The test consisted in observing whether the twin maternities were then related to birth order within this age range. He found that they were. Accordingly, he drew the inference that the second hypothesis was true.This led him [2] to question the evidence which had seemed to support hypothesis 1. Among the sorts of evidence he considered were the prompt postmarital conceptions [4,9] and prompt postwar conceptions [3,8] of DZ twins. He found that within the reproductive histories of women bearing DZ twins, the conception delays leading to first-born DZ twin pairs were less than those leading to first-born singletons. Though he admits that the difference was not significant, he writes: "It probably means that prompt conception is not a constant characteristic of parents of twins; their chance of early conception need not be any greater than that of other couples." It seems to me that (even if the difference were significant) the argument is misleading. The contrast that would be interesting is between the conception delays preceding first-born singletons in DZ twin sibships and the first conception delays in other sibships. If there were no difference between them, then Allen's suggestion would be vindicated.In support of his case, Allen writes [2]: "It seems as if the marriage event itself promotes twinning; and so does return of husbands from war, or an illicit love affair." 0001-5660/82/3101-02-0119S01.00

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Multiple births in Australia, 1944–63

Cited by 29 publications

References 22 publications

Comparison of Twinning Rates for Villages in Makarska Region, Croatia

Comparison of Twinning Rates for Villages in Makarska Region, Croatia

Coffee and Smoking as Risk Factors of Twin Pregnancies: The Danish National Birth Cohort

Dizygotic Twinning, Birth Order, Female Psychology, and Coital Rates

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