Maternal Age and Parity as Predictors of Human Twinning

Bønnelykke, Birgitte

doi:10.1017/s0001566000005237

Cited by 18 publications

(15 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similar to previous studies, we found that DZ twinning was strongly associated with older maternal age and mother's ethnicity 20–23 . Rates of twinning have been observed to be low in Hispanic populations; 19 however, this is one of the first studies to examine the rates of DZ and MZ twinning among Hispanics.…”

Section: Discussionsupporting

confidence: 88%

Rates of twinning before and after fortification of foods in the US with folic acid, Texas, 1996 to 1998

Waller

Tita

Annegers

2003

Paediatric Perinatal Epid

View full text Add to dashboard Cite

Several investigators have reported a 40% increase in the prevalence of twinning among women who have taken folic acid or multivitamins containing folic acid at the time of conception. Given that infant morbidity and mortality are greatly increased among twins, such a large increase in twinning could have serious implications. We undertook this study to determine if US fortification of enriched cereal-grain products with folic acid was associated with an unexpected increase in the prevalence of twinning in the state of Texas. We examined 1 003 207 deliveries conceived in Texas, between 1 January 1996 and 31 December 1998. We compared the prevalence of twin deliveries conceived before, during and after fortification with folic acid, mandated to begin on 1 January 1998. Comparing pregnancies conceived in 1997 with those conceived in 1996, we observed a 2.4% yearly increase in twinning, 1.024 [0.98, 1.07]. Comparing pregnancies conceived in 1998 with those conceived in 1997, we observed a 4.6% yearly increase in twinning, 1.046 [1.00, 1.09]. These increases were adjusted for maternal age, race, education, parity and season of conception. The size and pattern of these increases are consistent with the ongoing increase in twinning of 1-4% per year which began in the US prior to fortification.

show abstract

Section: Discussionsupporting

confidence: 88%

Rates of twinning before and after fortification of foods in the US with folic acid, Texas, 1996 to 1998

Waller

Tita

Annegers

2003

Paediatric Perinatal Epid

View full text Add to dashboard Cite

show abstract

“…The age-specific twinning rates (TWRs) for Finland for the periods 1951-1960, 1981-1990and 1991-2000. The periods are 1951-1960, in which the total TWR attains its highest value (15.5 per 1000), [1981][1982][1983][1984][1985][1986][1987][1988][1989][1990], for which it obtains it minimum (10.8 per 1000) and 1991-2000, for which a new increase in the total TWR has resulted in a twinning rate of 14.7 per 1000.…”

Section: Figurementioning

confidence: 99%

“…If the discrepancies between the results of direct and indirect standardization methods for Finland (Figure 1) are caused by the variation in the mean parity, then the parity effect in Denmark will only be slight. In fact, Bønnelykke (1990) stated that there was no association between DZ twinning and parity for mothers of all twins born alive in Denmark in 1984 and1985. This conclusion by Bønnelykke (1990) was drawn from logistic regression analysis where the association between DZ twinning and parity was adjusted for maternal age.…”

Section: Twin Research and Human Genetics October 2005mentioning

confidence: 99%

“…In fact, Bønnelykke (1990) stated that there was no association between DZ twinning and parity for mothers of all twins born alive in Denmark in 1984 and1985. This conclusion by Bønnelykke (1990) was drawn from logistic regression analysis where the association between DZ twinning and parity was adjusted for maternal age. This result is not in concordance with the majority of literature, although a few other authors have also previously failed to demonstrate this association (Dahlberg, 1926;Gedda, 1961;Lamy et al, 1955).…”

Section: Twin Research and Human Genetics October 2005mentioning

confidence: 99%

See 1 more Smart Citation

Variations in the Maternal Age Effect on Twinning Rates: The Nordic Experience

Fellman

Eriksson

2005

twin res hum genet

View full text Add to dashboard Cite

“…A high frequency of monozygotic pairs among children born to mothers older than 30 years was an unexpected event, since it is known that the monozygotic twinning rate declines as maternal age increases. 21,22 A small but significant difference (t = 2.422; P = 0.015) was observed when the maternal mean age for singletons (31.12 years ± 4.60) was compared to that for twins [31.93 years (SD 4.49)]. Twins also differed significantly from singletons in relation to the mean gestation order (1.82 for twins and 2.01 for singletons), the Mann-Whitney test resulting in Z = 2.97; P = 0.003.…”

mentioning

confidence: 99%

Twinning rate in a sample from a Brazilian hospital with a high standard of reproductive care

Colletto

Beiguelman

2001

Sao Paulo Med. J.

View full text Add to dashboard Cite

CONTEXT: Epidemiological studies on twin births have been motivated mostly by the positive correlation between twinning rate and human fertility, prematurity, low birth weight, increased risk of infant death and long term risk for morbidity. OBJECTIVE: This paper intends to estimate the incidence of multiple births in a private hospital in Brazil with a high standard of reproductive care, and to evaluate the effects of maternal age, gestation order and assisted fertilization on twinning rate. DESIGN: Retrospective analysis. SETTING: First-class tertiary private hospital, São Paulo, Brazil. PARTICIPANTS: The multiple birth rate was investigated among 7,997 deliveries from 1995 to 1998, including 7,786 singletons, 193 twins, 17 triplets and one quadruplet. RESULTS: The rates per 1,000 dizygotic and monozygotic pairs and for triplets were estimated as 19.51, 4.50 and 2.13, respectively. The dizygotic and triplet rates were the highest observed in Brazil up to the present day. The twinning rate among primigravidae older than 30 years was very high (45.02 per 1,000) and was due to a disproportionately high frequency of dizygotic pairs. The triplet rate was also very high among the mothers of this age group (5.71 per 1,000). These facts are strong indicators that these women were the ones most frequently submitted to assisted reproductive techniques. The mean maternal age of the studied population was about six years higher than that estimated for mothers in the general population of southeastern Brazil. Primigravidae aged under 30 years as well as multigravidae showed similar twinning rates, which were almost 20 per 1,000. Among the deliveries of multigravidae older than 30 years, an unusually high frequency of monozygotic twins was observed (7.04 per 1,000), probably as a consequence of the residual effect of long-term use of oral contraceptives. CONCLUSIONS: The dizygotic twinning rate increased from 13.51 to 28.98 per 1,000 over the four years studied, with the twinning rate for primigravidae over 30 years old in 1998 being twice that observed in 1995. The mean maternal age was also high during this period, but the extremely high increase in twinning rate observed cannot be attributed solely to this variable. Assisted fertilization seems to be the most probable cause of this unusually high twinning rate.

show abstract

Maternal Age and Parity as Predictors of Human Twinning

Cited by 18 publications

References 6 publications

Rates of twinning before and after fortification of foods in the US with folic acid, Texas, 1996 to 1998

Rates of twinning before and after fortification of foods in the US with folic acid, Texas, 1996 to 1998

Variations in the Maternal Age Effect on Twinning Rates: The Nordic Experience

Twinning rate in a sample from a Brazilian hospital with a high standard of reproductive care

Contact Info

Product

Resources

About